Review Article |
Corresponding author: Tai-Hui Li ( mycolab@263.net ) Academic editor: María P. Martín
© 2019 Ming Zhang, Tai-Hui Li, Chao-Qun Wang, Nian-Kai Zeng, Wang-Qiu Deng.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Zhang M, Li T-H, Wang C-Q, Zeng N-K, Deng W-Q (2019) Phylogenetic overview of Aureoboletus (Boletaceae, Boletales), with descriptions of six new species from China. MycoKeys 61: 111-145. https://doi.org/10.3897/mycokeys.61.47520
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In this study, species relationships of the genus Aureoboletus were studied, based on both morphological characteristics and a four-gene (nrLSU, tef1-a, rpb1 and rpb2) phylogenetic inference. Thirty-five species of the genus have been revealed worldwide, forming eight major clades in the phylogenetic tree, of which twenty-four species have been found in China, including six new species: A. glutinosus, A. griseorufescens, A. raphanaceus, A. sinobadius, A. solus, A. velutipes and a new combination A. miniatoaurantiacus (Bi & Loh) Ming Zhang, N.K. Zeng & T.H. Li proposed here. A key to 24 known Chinese species has been provided.
Boletes, molecular phylogeny, morphology, species identification, taxonomy
Aureoboletus Pouzar was circumscribed in 1957, based on the type species A. gentilis (Quél.) Pouzar (
The establishment and acceptance of the genus Aureoboletus has a long history. Xerocomus section Auripori
Recently, broad-scale molecular phylogenetic studies have been used to investigate phylogenetic relationships amongst the genera and species in Boletes. Aureoboletus was strongly supported as a genus in the Boletaceae, subfamily Xerocomoideae and has been shown to be closely related to Boletellus, Hemileccinum Šutara, Heimioporus E. Horak, Xerocomus etc. (
Numerous Aureoboletus specimens have been recently obtained in China, increasing the species diversity of Aureoboletus. In this study, the species richness and phylogenetic relationships were re-evaluated, based on detailed morphological observations and a four-gene phylogenetic inference. The aims were to 1) evaluate the phylogenetic relationships within the genus; 2) redefine the characteristics of Aureoboletus; 3) elucidate the species diversity of Aureoboletus in China; 4) describe the newly discovered species.
Photographs and records of basidiomata were obtained in the field. Specimens were dried in an electric drier and finally deposited in the Fungarium of Guangdong Institute of Microbiology (
Genomic DNA was extracted from the voucher specimens using the Sangon Fungus Genomic DNA Extraction kit (Sangon Biotech Co. Ltd., Shanghai, China), according to the manufacturer’s instructions. Primer pairs LR0R/LR5 or LR0R/LR7 (
Newly generated sequences and related sequences downloaded from GenBank were used to reconstruct phylogenetic trees. Detailed information of samples, including species name, voucher, locality, GenBank accession numbers and references, are given in Table
Taxon | Voucher | Country | LSU | tef1 | rpb1 | rpb2 | Reference |
---|---|---|---|---|---|---|---|
A. auriflammeus | DD973 | USA | AY612818 | _ | _ | _ | GenBank |
A. auriporus | MAN020 | Costa Rica | JQ003659 | _ | _ | _ |
|
BDCR0431 | Costa Rica | HQ161871 | _ | HQ161840 | _ |
|
|
A. cf. auriporus |
|
USA | MN410705 | _ | _ | _ | This study |
A. catenarius |
|
China | MN204514 | _ | MN473157 | _ | This study |
HKAS54463 | China | KT990509 | KT990710 | KT990890 | KT990348 |
|
|
HKAS54467 | China | KT990510 | KT990711 | _ | KT990349 |
|
|
A. citriniporus | REH8719 | USA | KF030298 | _ | _ | _ |
|
A. clavatus | GDGM42992 | China | MK123462 | MK165847 | _ | _ |
|
GDGM42962 | China | KR052045 | MK165846 | KR052056 | _ |
|
|
GDGM42963 | China | KR052046 | KR052054 | KR052057 | _ |
|
|
GDGM42984 | China | KR052047 | KR052055 | _ | _ |
|
|
A. duplicatoporus |
|
China | MN204515 | _ | MN473160 | _ | This study |
|
China | MN204517 | MN549677 | MN473167 | _ | This study | |
|
China | MN204516 | _ | MN473166 | MN549707 | This study | |
|
China | MN410708 | _ | MN473164 | _ | This study | |
|
China | MN204518 | MN549669 | MN473168 | _ | This study | |
|
China | MN204519 | _ | MN473173 | _ | This study | |
|
China | MN204520 | _ | MN473175 | _ | This study | |
HKAS50498 | China | KF112361 | KF112230 | KF112561 | KF112754 |
|
|
HKAS63009 | China | KT990511 | KT990712 | KT990891 | KT990350 |
|
|
HKAS83115 | China | KT990512 | KT990713 | KT990892 | KT990351 |
|
|
GDGM45133 | China | MK123455 | MK165834 | _ | MN549697 | This study | |
GDGM52889 | China | MK123456 | MK165835 | MN473163 | _ | This study | |
A. formosus | GDGM44441 | China | KT291749 | KT291744 | MN473152 | KT291751 | Zhang et al. 2015 |
GDGM44444 | China | KT291750 | MK165833 | MN473153 | KT291752 | Zhang et al. 2015 | |
A. gentilis | Pug1 | Germany | DQ534635 | KF030399 | _ | _ |
|
MG372a | Italy | KF112344 | KF134014 | KF112557 | KF112741 |
|
|
A. glutinosus |
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China | MN204522 | _ | _ | _ | This study |
|
China | MN204521 | _ | - | MN549699 | This study | |
GDGM44476 | China | MH670254 | MH700192 | _ | MH700228 | This study | |
GDGM44477 | China | MH670255 | MH700205 | _ | MH700229 | This study | |
GDGM44479 | China | MH670256 | MH700204 | _ | MH700230 | This study | |
GDGM44733 | China | MH670257 | MH700203 | _ | MH700231 | This study | |
GDGM44821 | China | MH670258 | _ | _ | MH700232 | This study | |
A. griseolorufescens | GDGM28490 | China | MH670278 | _ | _ | MH700241 | This study |
ZhangM131 | China | MH670279 | _ | MH700220 | MH700242 | This study | |
A. innixus | 136/98 | USA | DQ534639 | _ | _ | _ |
|
MB03-104 | USA | KF030239 | KF030400 | _ | _ |
|
|
136 | USA | KF030240 | _ | _ | _ |
|
|
A. liquidus | TNS:F-39710 | Japan | AB972886 | _ | _ | _ |
|
TNS:F-52265 | Japan | AB972884 | _ | _ | _ |
|
|
TNS:F-52267 | Japan | AB972885 | _ | _ | _ |
|
|
A. longicollis |
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China | MN204526 | _ | MN473172 | _ | This study |
|
China | MN204527 | _ | MN473179 | _ | This study | |
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China | MN204525 | _ | MN473161 | _ | This study | |
|
China | MN204524 | _ | MN473150 | MN549688 | This study | |
ZhangM56 | China | MN204528 | _ | MN473187 | _ | This study | |
GDGM43239 | China | MK123459 | MK165843 | MN473147 | _ | This study | |
HKAS80127 | China | KT990515 | KT990719 | _ | _ |
|
|
GDGM42849 | China | KR052051 | _ | KR052058 | _ |
|
|
HKAS53398 | China | KF112376 | KF112238 | KF112625 | KF112755 |
|
|
HKAS84679 | China | KT990514 | KT990718 | _ | KT990356 |
|
|
HKAS80489 | China | KT990523 | KT990727 | _ | KT990364 |
|
|
GDGM44734 | China | MK123458 | MK165842 | MN473155 | MN549692 | This study | |
GDGM53336 | China | MK123460 | MK165844 | MN473170 | MN5497018 | This study | |
GDGM44739 | China | MK123461 | MK165845 | MN473156 | MN549693 | This study | |
A. marronius | GDGM43288 | China | KJ488958 | KT291746 | _ | KT291753 |
|
A. miniatoaurantiacus |
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China | MN204533 | _ | MN473181 | MN549711 | This study |
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China | MN204532 | MN549678 | MN473171 | MN549709 | This study | |
|
China | MN204530 | _ | MN473149 | MN549687 | This study | |
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China | MN204529 | MN549671 | MN473148 | MN549686 | This study | |
|
China | MN204531 | _ | MN473154 | MN549691 | This study | |
GDGM53501 | China | MH670262 | MH700199 | MH700217 | _ | This study | |
Zeng1625 | China | MH670263 | _ | _ | _ | This study | |
Zeng1294 | China | MH670264 | MH700198 | _ | _ | This study | |
Zeng1323 | China | MH670265 | MH700197 | _ | _ | This study | |
Zeng1339 | China | MH670266 | MH700196 | _ | _ | This study | |
Zeng664 | China | MH670267 | MH700195 | _ | _ | This study | |
HKAS59694 | China | KT990513 | KT990714 | KT990893 | KT990352 |
|
|
GDGM42855 | China | MH670259 | MH700202 | MH700214 | MH700233 | This study | |
GDGM53274 | China | MH670260 | MH700201 | MH700215 | MH700234 | This study | |
GDGM52888 | China | MH670261 | MH700200 | MH700216 | MH700235 | This study | |
A. mirabilis | REH9765 | USA | KP327661 | KP327661 | _ | _ |
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CBS-136.60 | Germany | AF050652 | _ | _ | _ |
|
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HKAS57776 | China | KF112360 | KF112229 | KF112624 | KF112743 |
|
|
REH8717 | USA | KF030299 | _ | _ | _ |
|
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A. moravicus | Xle1 | Germany | _ | KF030403 | _ | _ |
|
MG374a | Italy | KF112421 | KF112232 | KF112559 | KF112745 |
|
|
A. nephrosporus | HKAS67931 | China | KT990516 | KT990720 | KT99089 | KT990357 |
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HKAS74929 | China | KT990517 | KT990721 | KT990896 | KT990358 |
|
|
A. novoguineensis | K-A/7 | Japan | DQ534637 | _ | _ | _ |
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A. projectellus | MB-03-118 | USA | NG027638 | _ | _ | _ | GenBank |
NYBG13392 | USA | KP327622 | KP327675 | _ | _ |
|
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Sn2Hor | USA | KF030300 | _ | _ | _ |
|
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NYBG13393 | USA | KP327623 | KP327676 | _ | _ |
|
|
ID-713 | USA | DQ534582 | AY879116 | AY788850 | AY787218 |
|
|
A. quercus-spinosae |
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China | KY039966 | MK165839 | KY039962 | KY039957 |
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GDGM43757 | China | KY039966 | MK165839 | KY039962 | KY039957 |
|
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GDGM43755 | China | KY039967 | MK165836 | KY039963 | KY039958 |
|
|
GDGM43758 | China | KY039968 | MK165837 | KY039964 | KY039959 |
|
|
GDGM43786 | China | KY039969 | MK165838 | KY039965 | KY039960 |
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|
A. raphanaceus |
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China | MN204536 | MN549673 | _ | MN549700 | This study |
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China | MN204538 | MN549674 | _ | MN549702 | This study | |
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China | MN204535 | _ | _ | MN549698 | This study | |
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China | MN204539 | MN549675 | _ | _ | This study | |
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China | MN204537 | _ | _ | MN549701 | This study | |
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China | MN204540 | MN549676 | MN473165 | MN549706 | This study | |
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China | MN204541 | _ | MN473166 | MN549707 | This study | |
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China | MN204534 | _ | MN473146 | MN549685 | This study | |
GDGM52543 | China | MH670271 | _ | _ | _ | This study | |
GDGM44832 | China | MH670268 | MH700194 | MH700218 | MH700236 | This study | |
GDGM50266 | China | MH670269 | _ | _ | MH700237 | This study | |
GDGM46333 | China | MH670270 | _ | _ | MH700238 | This study | |
GDGM52590 | China | MH670272 | MH700193 | MH700219 | MN549704 | This study | |
A. roxanae | DS626-7 | USA | KF030311 | KF030402 | KF030381 | _ |
|
A. rubellus | GDGM52382 | China | MH670273 | _ | _ | MH700239 | This study |
GDGM52367 | China | MH670274 | _ | _ | MH700240 | This study | |
A. shichianus | HKAS43373 | China | AY647211 | _ | _ | _ | GenBank |
HKAS76852 | China | KF112419 | KF112237 | KF112562 | KF112756 |
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A. sinobadius | GDGM75499 | China | MN204551 | _ | MN473182 | _ | This study |
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China | MN204547 | _ | _ | _ | This study | |
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China | MN204546 | _ | _ | _ | This study | |
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China | MN204545 | _ | _ | _ | This study | |
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China | MN204548 | _ | MN473176 | _ | This study | |
A. sinobadius |
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China | MN204544 | _ | _ | _ | This study |
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China | MN204549 | _ | MN473177 | _ | This study | |
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China | MN204543 | _ | MN473159 | _ | This study | |
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China | MN204550 | _ | MN473180 | _ | This study | |
GDGM44473 | China | MH670250 | MH700189 | MH700211 | _ | This study | |
GDGM43275 | China | MH6702464 | MH700185 | MH700208 | MH700221 | This study | |
GDGM44732 | China | MH670247 | MH700186 | MH700207 | MH700222 | This study | |
GDGM44730 | China | MH670248 | MH700187 | MH700209 | MH700223 | This study | |
GDGM44736 | China | MH670249 | MH700188 | MH700210 | MH700224 | This study | |
A. solus | GDGM46222 | China | MH670275 | _ | _ | _ | This study |
GDGM44759 | China | MH670276 | MH700206 | _ | _ | This study | |
GDGM42822 | China | MH670277 | _ | _ | _ | This study | |
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China | MN410707 | _ | _ | _ | This study | |
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China | MN204553 | _ | _ | _ | This study | |
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China | MN204552 | _ | _ | _ | This study | |
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China | MN204555 | _ | _ | _ | This study | |
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China | MN204554 | _ | _ | _ | This study | |
Aureoboletus sp. |
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China | MN410706 | _ | MN473158 | _ | This study |
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China | MN204556 | _ | MN473174 | MN549710 | This study | |
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China | MN204513 | _ | _ | _ | This study | |
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China | MN204511 | _ | _ | _ | This study | |
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China | MN204512 | _ | _ | _ | This study | |
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China | MN204509 | MN549672 | _ | MN549680 | This study | |
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China | MN204523 | _ | MN473162 | MN549703 | This study | |
LAM-0466 | Malaysia | KY091058 | _ | _ | _ | GenBank | |
HKAS53458 | China | KF112456 | KF112231 | KF112558 | KF112742 | This study | |
GDGM44829 | China | KY039970 | _ | _ | KY039961 | This study | |
GDGM44831 | China | KY039971 | MK165840 | _ | MN549696 | This study | |
GDGM44469 | China | KP319028 | MK165841 | _ | MN549690 | This study | |
A. tenuis | GDGM42601 | China | KF534789 | KT291745 | _ | KT291754 | Zhang et al. 2013 |
A. thibetanus | HKAS76655 | China | KF112420 | KF112236 | KF112626 | KF112752 |
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GDGM43283 | China | KJ907380 | KT291747 | _ | KT291755 |
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GDGM43284 | China | KJ90738 | KT291748 | _ | KT291756 |
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HKAS57692 | China | KT990524 | KT990728 | KT990901 | KT990365 |
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HKAS89494 | China | KT990525 | KT990729 | KT990902 | KT990366 |
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A. velutipes | GDGM52409 | China | MH670252 | _ | _ | MH700225 | This study |
GDGM44713 | China | MH670253 | MH700191 | MH700213 | MH700226 | This study | |
GDGM42608 | China | MH670251 | MH700190 | MH700212 | MN549683 | This study | |
A. cf. venustus | ZhangM142 | China | MN204558 | MN549668 | MN473186 | MN549714 | This study |
A-2 | China | MN204557 | MN549679 | MN473185 | MN549713 | This study | |
GDGM42800 | China | MK123463 | _ | MN473187 | MN549684 | This study | |
A. venustus | HKAS82183 | China | KU321705 | _ | _ | _ |
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HKAS77700 | China | KU321703 | _ | _ | _ |
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A. viridiflavus | DD972 | USA | AY612805 | _ | _ | _ | GenBank |
A. viscidipes |
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China | MN204510 | _ | _ | MN549694 | This study |
HKAS77103 | China | KT990519 | KT990723 | _ | KT990360 |
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GDGM44820 | China | MK123457 | _ | _ | MN549695 | This study | |
A. yunnanensis |
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China | MN204560 | MN549670 | MN473145 | MN549681 | This study |
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China | MN204559 | _ | MN473144 | MN549682 | This study | |
HKAS57581 | China | KF112422 | KF112233 | KF112560 | KF112746 |
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HKAS75050 | China | KT990520 | KT990724 | KT990898 | KT990361 |
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A. zangii |
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China | MN204563 | - | MN473183 | MN549712 | This study |
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China | MN204561 | _ | _ | _ | This study | |
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China | MN204562 | _ | MN473151 | MN549689 | This study | |
HKAS63217 | China | KT990526 | _ | _ | _ |
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HKAS74751 | China | KT990521 | KT990725 | KT990899 | KT990362 |
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HKAS74766 | China | KT990522 | KT990726 | KT990900 | KT990363 |
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P. imbricatus | HKAS68642 | China | KF112398 | KF112299 | KF112637 | KF112786 |
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X. aff. subtomentosus | HKAS58865 | China | KF112389 | KF112294 | KF112630 | KF112784 |
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The combined final dataset was analysed using RAxML v7.2.6 (
For phylogenetic analyses, 304 (102 nrLSU, 59 tef1-a, 71 rpb1 and 72 rpb2) new sequences from 105 Aureoboletus collections and 171 GenBank downloaded sequences from 68 Aureoboletus samples were used as ingroups. Four sequences of P. imbricatus and X. subtomentosus, respectively, retrieved from GenBank were used as outgroups. The combined matrix of 175 samples with 3018 nucleotide sites was submitted to TreeBASE (Submission ID 25249). HKY+G, GTR+I+G, SYM+I and SYM+G were chosen as the best substitution models for nrLSU, tef1-a, rpb1 and rpb2, respectively. ML and BI analyses generated almost identical tree topologies with minimal variations in statistical support values. Thus, only a ML tree is displayed (Fig.
Maximum likelihood tree from a RAXML search using the GTRGAMMA model, illustrating the phylogeny of Aureoboletus and related taxa in Boletales, based on a multilocus (nrLSU, tef1-a, rpb1 and rpb2) dataset. Phylloporus imbricatus N.K. Zeng, Zhu L. Yang & L.P. Tang and Xerocomus subtomentosus (L.) Quél. are chosen as outgroups. The lineages with new species and new combination are bold in the tree. Branches are labelled with maximum likelihood bootstrap higher than 70% and Bayesian posterior probabilities more than 0.95.
In the multi-gene phylogenetic trees, the monophyly of Aureoboletus was statistically strongly supported (BS = 100, PP = 1); eight well supported main clades, labelled as Clade I to VIII, are shown and six well supported (BS = 100, PP = 1) new species lineages were recognised. In Clade I, nine known species [A. auriporus (Peck) Pouza, A. duplicatoporus (M. Zang) G. Wu & Zhu L. Yang, A. formosus Ming Zhang & T.H. Li, A. gentilis (Quél.) Pouzar, A. novoguineensis Hongo, A. quercus-spinosae Ming Zhang & T.H. Li, A. venustus Fang Li, Kuan Zhao & Qing Li Deng, A. viridiflavus Coker & Beers ex Klofac and A. zangii X.F. Shi & P.G. Liu] were presented, including the type species A. gentilis and a new lineage (lineage I) discovered in this study. Lineage I is presented as a sister group to A. novoguineensis with significant statistical support (BS = 100, PP = 1). Clade II comprised five known species [A. catenarius G. Wu & Zhu L. Yang, A. citriniporus (Halling) Klofac, A. moravicus (Vaček) Klofac, A. roxanae (Frost) Klofac and A. yunnanensis G. Wu & Zhu L. Yang], a new lineage (lineage II) and three unnamed sequences. Lineage II is closely related to an unnamed sample (GDGM71707) from southern China. Clade III is composed of six species, [A. longicollis (Ces.) N.K. Zeng & Ming Zhang, A. marroninus T.H. Li & Ming Zhang, A. tenuis T.H. Li & Ming Zhang, A. thibetanus (Pat.) Hongo & Nagas., A. viscidipes (Hongo) G. Wu & Zhu L. Yang] and a new lineage (lineage III), all of which are from Asia. Clade IV was comprised of the North American species A. auriflammeus (Berk. & M.A. Curtis) G. Wu & Zhu L. Yang and a new species combination from China. Clade V included five strongly supported species level groups [A. innixus (Frost) Halling, A.R. Bessette & Bessette, A. nephrosporus G. Wu & Zhu L. Yang, A. rubellus Kuan Zhao & G. Wu] and two new lineages (lineage IV and lineage V). Clade VI included four known species [A. mirabilis (Murrill) Halling, A. projectellus (Murrill) Halling, A. russellii (Frost) G. Wu & Zhu L. Yang from North America and A. shichianus (Teng & L. Ling) G. Wu & Zhu L. Yang from China]. Clade VII had a single species, A. clavatus N.K. Zeng & Ming Zhang, which was recently reported in southern China. Clade VIII represents a single new lineage (lineage VI), which is the basal group of the genus Aureoboletus.
. Aureoboletus gentilis (Quél.) Pouzar.
Basidiomata small to large. Pileus viscid, dry or sticky when wet, even or smooth to wrinkled, usually subtomentose, rarely glabrous, with or without veil or velar residues hanging at margin. Context white to yellowish-white, usually pinkish to reddish-brown beneath pileipellis, unchanging or changing blue or greenish or pastel red when exposed. Tubes coloured with all kinds of yellows, pale yellow, golden yellow to bright yellow, unchanging or slightly changing to blue when bruised, pores circular to angular, smaller to larger, somewhat relatively larger and shallowly depressed around the stipe, concolorous with tubes. Stipe central, cylindrical or clavate, surface glabrous to striate fibrillose, never or rare forming reticulation or Leccinum-like scabrous, dry to viscid, with white basal mycelium. Basidiospores smooth to verrucose or longitudinally striate, subfusiform, oblong ovoid to subglobose, yellowish to yellowish-brown in KOH. Hymenophoral trama boletoid, composed of subcylindrical to cylindrical hyphae, colourless. Pleurocystidia fusiform to subclavate, thin- or thick-walled, sometimes containing golden-yellow contents at first, then gradually changing to yellowish-white to hyaline in 5% KOH. Cheilocystidia present, infrequent or absent, usually similar to pleurocystidia in shape and size, if present. Pileipellis as an interwoven trichoderm, trichoderm or ixotrichoderm, consisting of erect hyphae which are occasionally branched, cylindrical to clavate, thin- to slightly thick-walled, usually less than 1 μm. Stipitipellis hymeniform, as an ixotrichoderm to intricated ixotrichoderm. Caulocystidia clavate, fusoid or ventricose-fusoid. Stipe trama composed of parallel hyphae. Clamp connections absent.
World-wide distribution, mainly known from subtropical Asia and temperate zones of the Northern hemisphere, growing on the ground associated with Fagaceae and other broadleaf trees.
This species is distinguished from other Aureoboletus taxa by its smaller and glutinous basidiomata, reddish-brown to ruby pileus usually with irregular reticulation and darker folds, gelatinised veil remnants and smooth basidiospores 10–13.5 × 4.5–5 µm in size.
“glutinosus” refers to the glutinous basidiomata.
China, Hunan Province, Rucheng Town, Jiulongjiang National Forest Park, on soil and usually growing amongst the mosses under the broadleaf forest, at 25°38'N, 113°77'E, alt. 300 m, 8 May 2014, M. Zhang (holotype: GDGM44477).
Basidiomata small-sized. Pileus 1–2 cm wide, obtuse to convex, becoming broadly convex to plane, fleshy, viscid, especially when young and wet, reddish-brown, violet brown to greyish-ruby (9E6–12E6, 9E7–12E7), slightly fading to pale yellow (2A3–4A3) towards margin, usually forming a pale yellow to even nearly white zone at margin, distinctly wrinkled and often reticulate irregularly with somewhat darker folds at centre, strongly glutinous or mucilaginous when fresh; margin somewhat involute to nearly flat, often attached with yellowish-white to subhyaline and strongly gelatinised veil remnants. Context 2–5 mm thick at stipe, firm and tough in youth, soft when matured, white on the whole, greyish-red (10B5–11B5) beneath pileipellis, practically unchanging to becoming slightly greyish-pinkish or greyish-red (10B5–11B5) when exposed. Tubes 7–10 mm deep, distinctly depressed around stipe, yellowish-white (2A2–4A2) when young, becoming pale yellow, greyish-yellow, pastel yellow to olive yellow (2A3–4A3, 1B3–2B3, 2A4–3A4, 2C6–3C6) with age, often with an olive tint, unchanging when bruised. Pores 0.3–0.5 mm in diam., mostly subangular, slightly radially elongated around stipe at maturity, smaller near pileus margin, concolorous with tubes. Stipe 15–40 × 2–4 mm, central, cylindrical or narrowly clavate, solid, equal to slightly tender downwards, greyish-orange (6B4), greyish-red (7B4) to brownish-orange (6C4–7C4), without reticulation, smooth to faintly longitudinally striate, gelatinous or strongly viscid when young and wet, usually covered with a mucilaginous layer, with white basal mycelium. Odour not distinct. Taste mild.
Basidiospores [150/4/4] (9.5–)10–13.5 × (4–)4.5–5 µm, Q = (2.2–)2.3–2.5(–2.7), Qm = 2.48 ± 0.18, subfusiform and inequilateral in side view, oblong in ventral view, smooth, yellowish to yellowish-brown in 5% KOH and yellow brown to dark brown in Melzer’s reagent, thin-walled. Basidia 20–30 × 7–10 µm, clavate, 4-spored, sterigmata 2–4.5 µm long, yellowish-white to hyaline in 5% KOH, without basal clamps. Pleurocystidia 35–60 × 8–13 μm, fusiform, thin-walled. Cheilocystidia frequent, similar to pleurocystidia in shape and size. Hymenophoral trama composed of subparallel hyphae 4–10 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis an ixotrichodermium of erect hyphae 5–12 μm in diameter, branched, yellowish-white to hyaline in 5% KOH, dextrinoid in Melzer’s reagent; terminal cells 27–50 × 7–12 µm, cylindrical, clavate or nearly fusoid. Stipitipellis a layer of repent to suberect branching hyphae 3–6 μm in diam., hyaline in 5% KOH. Clamp connections absent in all tissues.
Solitary or scattered on ground with humus and debris, usually growing amongst the mosses (Fissidens sp. and Pottiaceae sp.) under Fagaceae, mixed with other broadleaf trees, alt. 300–500 m; May to July, known from Guangdong and Anhui Province.
China, Hunan Province, Chenzhou City, Rucheng Town, Jiulongjian National Forest Park, 8 May 2014, H. Huang (GDGM44476); Same location, 12 June 2015, M. Zhang (GDGM44733); Anhui Province, Huangshan City, Huangshan National Forest Park, 27 July 2015, C.H. Li (GDGM44821).
Phylogenetic analyses showed that A. glutinosus is closely related to A. marroninus, A. tenuis, A. thibetanus and A. viscidipes; however, the independent phylogenetic position and different morphological characters can distinguish A. glutinosus from these similar species. Aureoboletus marroninus differs in having a more wrinkled and darker (violet brown or maroon) pileus, white context and smaller basidiospores 8.5–10 × 4–4.5 µm (
Basidiomata of six new species and one new combination of Aureoboletus from China. A, B A. glutinosus (A GDGM44476 B GDGM44477, holotype) C A. griseorufescens (GDGM28490, holotype) D, E A. miniatoaurantiacus (D GDGM43439 E GDGM43282) F, G A. raphanaceus (F GDGM45911, holotype G GDGM52890) H, I A. sinobadius (H GDGM44732 I
Scanning electron micrograph of basidiospores of six new species and one new combination of Aureoboletus from China. A A. glutinosus (GDGM44477, holotype) B A. griseorufescens (GDGM28490, holotype) C, D A. miniatoaurantiacus (C GDGM43439 D GDGM4855) E, F A. raphanaceus (GDGM45911, holotype) G A. sinobadius (GDGM71932, holotype) H A. solus (GDGM44759, holotype) I A. velutipes (GDGM44713, holotype). Scale bars: 5 µm.
This taxon can be distinguished from other Aureoboletus species by its brownish-orange to ruby pileus colour, white to yellowish-white context changing to greyish-red or greyish-rose when exposed, light yellow tubes and comparatively small basidiospores 9–10.5 × 4.5–5 μm.
“griseorufescens” refers to the greyish-red discolouration of context when exposed or bruised.
China, Guangdong Province, Shaoguan City, Chebaling National Natural Reserve, on soil under the broadleaf forest dominated by Fagaceae trees, alt. 300 m, 23°22'N, 113°42'E, 15 July 2008, C.Y. Deng (holotype: GDGM28490) .
Basidiomata small to medium-sized. Pileus 2–5 cm wide, hemispheric when young, becoming convex to nearly plane in age, fleshy, subviscid or slightly viscid when wet, glabrous to minutely velvet-subtomentose, slightly wrinkled to rugulose, even or nearly so at margin, brownish-orange, brownish-red, dark red to greyish-ruby (6C6–7 to 11C6–7). Context 3–6 mm thick at centre, firm and tough, white to yellowish-white (2A1–2 to 3A1–2), more or less greyish-red (9C4–11C4) beneath the pileipellis and browner at the border line adjacent to tubes, gradually changing to greyish-red (9C4–11C4) to greyish-rose (12B5) when exposed. Tubes 2–4 mm deep, light yellow, yellow, pastel yellow to greenish-yellow (2A5, 3A4–6), unchanging when bruised. Pores small, 1–2 per mm, circular to angular, somewhat relatively larger and shallowly depressed around the stipe at maturity, concolorous with tubes, unchanging when bruised. Stipe 35–60 × 4–10 mm, central, cylindrical or clavate, equal to slightly enlarged downwards, smooth, viscid in wet condition, concolorous with pileus, pale in the apex. Stipe context white to reddish-white (9A2–11A2), gradually changing to greyish-red (9C4–11D5) to greyish-rose (12B5) when exposed, especially in the lower part. Basal mycelium white. Odour none. Taste mild.
Basidiospores [50/2/2] (8–)9–10.5(–11) × (4–)4.5–5(–5.5) μm, Q = (1.8–)2–2.2 (2.6), Qm = 2.19 ± 0.18, subfusiform and inequilateral in side view, oblong in ventral view, smooth, yellowish to yellowish-brown in 5% KOH and yellow brown to dark brown in Melzer’s reagent, thin-walled. Basidia 4-spored 25–30 × 7–11 μm, clavate, yellowish-white to hyaline in 5% KOH, sterigmata 2–3 μm. Cheilocystidia infrequent. Pleurocystidia 43–70 × 8–13 μm, fusiform, thin-walled, yellowish-white to hyaline in 5% KOH. Hymenophoral trama composed of subparallel hyphae 5–8 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis an entangled trichodermium of erect hyphae 12–19 μm in diameter, branched, yellowish-white to hyaline in 5% KOH, yellow brown to dark brown in Melzer’s reagent, terminal cells 20–50 × 6–10 μm, cylindrical, clavate or nearly fusoid. Stipitipellis a tangled layer of repent to suberect branching hyphae 7–10 μm in diam., hyaline in 5% KOH, with terminal cells 22–30 × 7–18 μm. Caulocystidia 43–58 × 12–18 μm, numerous, in clusters, clavate, fusoid or fusoid ventricose, mostly clavate, swollen at apex and usually contain yellow to yellowish-brown substance at an early stage in 5% KOH. Clamp connections absent in all tissues.
Solitary or scattered on ground with humus and debris under Fagaceae trees, mixed with other broadleaf trees, alt. 200–400 m; June to September; currently only known from southern China.
China, Hainan Province, Changjiang County, Bawangling National Forest Park, 7 July 2013, M. Zhang (ZhangM131).
Aureoboletus griseorufescens is somewhat similar to the recently reported species A. venustus from southern China; however, the latter taxon differs in having relatively larger (pileus up to 8 cm) and more viscous basidiomata, a reddish-orange pileus and broader basidiospores 7.5–10.5 × 5–6 μm (
This species can be easily distinguished from other Aureoboletus taxa by its dry and yellowish-white to pinkish-white pileus covered with fibrillose to tomentose squamules, radish smell and ovoid basidiospores 7.5–9 × 5–6 μm.
“raphanaceus” refers to the radish smell of the new species.
China, Jiangxi Province, Chongyi Town, Yangling National Forest Park, on soil under the broadleaf forest dominated by Fagaceae trees, at 25°28'N, 114°19'E, alt. 300 m, 1 September 2016, H. Huang (holotype: GDGM45911).
Basidiomata small to medium-sized. Pileus 3–8 cm wide, hemispheric when young, becoming convex to nearly plane in age, fleshy, dry or slightly viscid when wet, covered with greenish-grey, yellowish-grey to brownish-grey (1D2–10D2) fibrillose to tomentose squamules on yellowish-white (1A2–4A2) to pinkish-white background, slightly wrinkled at disc; margin thin, slightly incurved at first, then extending. Context 8–12 mm thick at centre, firm and tough in youth, becoming soft, white, more or less pinkish, brownish-orange (5C4–7C4), greyish-red (8C4–10C4) to light brown (5D4–7D4) beneath the pileipellis, unchanging or slightly changing blue near the hymenophore when exposed. Tubes 4–7 mm deep, greyish-yellow (1B5–3B5), light yellow (1A5–3A5) to yellow (2A7–3A7), unchanging when bruised. Pores small, 0.5–1 per mm, circular to angular, somewhat relatively larger and shallowly depressed around the stipe at maturity; pore-surface concolorous with tubes, unchanging when hurt. Stipe 20–40 × 8–15 mm, central, cylindrical or clavate, equal to slightly enlarged downwards, dry, concolorous with pileus, longitudinally streaked and faintly pruinose or tomentose, with a very pale flush of pastel red (8A5–10A5) zone at apex. Stipe context white to yellowish-white, slightly changing pale yellow (2A3–4A3) when exposed, especially in the lower part. Basal mycelium white. Odour as radish. Taste mild.
Basidiospores [80/3/3] (7–)7.5–9(–10) × 5–6 μm, Q= (1.27–)1.45–1.6(–1.7), Qm = 1.51 ± 0.08, ovoid and inequilateral in side view, ovoid in ventral view, smooth, yellowish to pale brown in 5% KOH and yellowish-brown in Melzer’s reagent, thin-walled. Basidia 20–30 × 8–11 μm, clavate, 4-spored, rarely 1-, 2-, 3-spored, yellowish-white to hyaline in 5% KOH, without basal clamps, sterigmata 2–3.5 µm long. Pleurocystidia 30–60 × 8–13 μm, fusiform, thin-walled, usually containing golden-yellow contents at first, gradually changing yellowish-white to hyaline in 5% KOH. Cheilocystidia infrequent, similar to pleurocystidia in shape and size. Hymenophoral trama composed of subparallel hyphae 5–23 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis an ixotrichodermium to trichodermium of erect hyphae 4–12 μm in diameter, usually covered with yellow to brownish-yellow pigment slightly dissolving in 5% KOH, branched, yellowish-white to hyaline in 5% KOH, dextrinoid in Melzer’s reagent; terminal cells cylindrical, clavate or nearly fusoid. Stipitipellis a layer of suberect branching hyphae 4–15 μm in diameter, hyaline in 5% KOH. Caulocystidia 30–60 × 8–12 μm, numerous, in clusters, fusiform to lageniform and usually contain yellow to yellowish-brown substance in an early stage in 5% KOH. Clamp connections absent in all tissues.
Solitary or scattered on ground with humus and debris under Fagaceae trees mixed with other broadleaf trees, alt. 300–1300 m; June to September; Currently known from Jiangxi and Hunan Province.
China, Jiangxi Province, Chongyi County, Yangling National Forest Park, alt. 550 m, 1 September 2016, M. Zhang (GDGM52908); Same locality and date B. Song (GDGM53127), M. Zhang (GDGM52266 and GDGM50266), H Huang (GDGM52890); Hunan Province, Guidong Town, Bamianshan National Nature Reserve, alt. 1250 m, 18 June 2016, Z.P. Song (GDGM52543 and GDGM46333).
The yellowish-white basidioma colour makes it easy to distinguish A. raphanaceus from the other species. Boletus orientialbus N.K. Zeng & Zhu L. Yang recently described from China is somewhat similar to A. raphanaceus in colour; however, B. orientialbus differs in having more robust basidiomata, smooth pileus, reticulate stipe and smaller basidiospores 7–10 × 4.5– 5 μm (
This species is distinguished from other Aureoboletus species by its pastel red to reddish-brown pileus, light yellow hymenophore unchanging when bruised, salty taste and two different shapes of basidiospores.
“sino-” refers China, the holotype’s location of the species; “badius” means the brownish-red or chestnut pileus colour.
China, Guangdong Province, Guangzhou City, Baiyun Mountain Scenic Area, on soil and usually growing amongst moss under broadleaf forest, dominated by Fagaceae trees, alt. 280 m, 18 May 2018, M. Zhang (holotype: GDGM71932).
Basidiomata medium to large-sized. Pileus 5–10 cm wide, hemispheric when young, becoming convex to nearly plane in age, fleshy, viscid, especially when young and wet, glabrous to minutely velvet-subtomentose, slightly wrinkled, usually violet brown (10E5–8 to 12E5–8) when young, gradually fading to pastel red (8A5–10A5), brownish-red (9C7–10C7), reddish-brown to brownish-violet (9D6–11D6, 9D7–11D7) at maturity, with a thin and slightly incurved margin. Context 7–10 mm thick at centre, firm and tough in youth and later soft, white to yellowish-white, and more or less greyish-red (9C4–10C4) beneath the pileipellis, slightly changing to greyish-red (9C4–10D5) when exposed. Tubes 8–15 mm deep, light yellow to greenish-yellow (2A5, 2B5), unchanging when bruised. Pores small, 1–1.5 per mm, circular to angular, somewhat relatively larger and shallowly depressed around the stipe at maturity, unchanging when bruised; pore-surface concolorous with tubes. Stipe 40–80 × 5–9 mm, central, cylindrical or clavate, equal to slightly enlarged downwards, smooth, viscid when wet, pastel red (8A5–10A5), with a very pale flush of pale orange (5A3–6A3) fibrous stripe. Stipe context white to yellowish-white, slightly changing to greyish-red (9C4–10D5) when bruised. Basal mycelium white. Odour mild. Taste salty.
Basidiospores [150/8/5] 10–13(–14) × (4–) 4.5–5 (–5.5) μm, average 11.5–12.5 × 4.5–5, Q = (–2) 2.3–2.67 (–2.88), Qm = 2.44 ± 0.22, subfusiform and inequilateral in side view with an obtuse apex, oblong to ovoid in ventral view, smooth, yellowish to yellowish-brown in 5% KOH, yellow brown to dark brown in Melzer’s reagent, occasionally two different shapes in some specimens. Basidia 22–33 × 8–11 μm, clavate, predominantly 4-spored, partially 2-spored, with sterigmata 2–4 µm long, yellowish-white to hyaline in 5% KOH, without basal clamp. Pleurocystidia 27–50 × 7–13 μm, fusiform, thin-walled, usually containing golden-yellow contents at first, gradually changing from yellowish-white to hyaline in 5% KOH. Cheilocystidia frequent, 23–48 × 9–15 μm, clavate to subfusiform, thin-walled, containing golden-yellow contents at first, gradually changing yellowish-white to hyaline in 5% KOH. Hymenophoral trama composed of subparallel hyphae 4–10 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis an ixotrichodermium of erect and branched hyphae 6–12 μm in diameter, yellowish-white to hyaline in 5% KOH, dextrinoid in Melzer’s reagent; terminal cells 35–60 × 5–10 μm, cylindrical, clavate or nearly fusoid. Stipitipellis a layer of repent to suberect branched hyphae 3–10 μm in diam., hyaline in 5% KOH. Caulocystidia 30–45 × 9–18 μm, mostly swollen clavate, usually containing yellow to yellowish-brown substance at an early stage in 5% KOH. Clamp connections absent in all tissues.
Solitary or scattered on ground with humus and debris under Castanopsis fissa Rehder E.H. Wilson mixed with other broadleaf trees, alt. 200–300 m; known from south China.
China, Guangdong Province, Guangzhou City, Baiyun Mountain Scenic Area, alt. 300 m, 4 June 2015, M. Zhang (GDGM44736 and GDGM44732); Same location, alt. 300 m, 30 May 2013, M. Zhang (GDGM43275); Same location, alt. 300 m, 4 June 2013, M. Zhang (ZhangM55); Same location, alt. 280 m, 14 May 2015, M. Zhang (GDGM45920); Guangdong Province, Huizhou City, Xiangtoushan National Nature Reserve, alt. 300 m, 2 April 2015, M. Zhang (GDGM44473); Hunan Province, Chenzhou City, Jiulongjiang National Forest Park, alt. 280 m, 13 June 2015, M. Zhang (GDGM44730); Guangzhou City, Research Institute of Tropical Forestry, alt. 200 m, 4 May 2018, J. Xu (GDGM72253).
Aureoboletus sinobadius is morphologically similar to A. auriporus, A. flaviporus (Earle) Klofac, A. gentilis, A. novoguineensis and A. venustus. However, A. auriporus differs from A. sinobadius in the pinkish cinnamon, vinaceous to vinaceous brown pileus, longer and more robust stipe covered with yellow pruina or floccosity at apex, slight acid taste and broader basidiospores 11–16 × 4–6 μm (
This species can be easily distinguished from other Aureoboletus taxa by its dry and small basidiomata, brownish-yellow to greyish-red pileus, glabrous stipe and smaller basidiospores (7–)8–10.5(–11) × (4–)4.5–5 μm.
“solus” refers to the solitary habit.
China, Guangdong Province, Shaoguan City, Nanling National Nature Reserve, on soil under the broadleaf forest, dominated by Fagaceae trees, 16 June 2015, M. Zhang (holotype: GDGM44759).
Basidiomata small-sized. Pileus 1.5–2.5 cm wide, hemispheric when young, becoming convex to nearly plane in age, fleshy, dry or slightly viscid when wet, minutely velvet subtomentose, slightly wrinkled, brownish-yellow, brownish-orange, brownish-red to greyish-red (5C7–8C7, 5C5–9C5); margin thin, slightly incurved at first, becoming nearly straight, often appendiculate with small membranous remains of the veil. Context 2–6 mm thick at centre, firm and tough in youth, becoming soft, white, more or less greyish-red (9C5–11C5) to brownish-red (9C7–11C7) beneath the pileipellis, unchanging when exposed. Tubes 2–3 mm deep, gr-yish-yellow (1B5–3B5), light yellow (1A5–3A5) to vivid yellow (1A8–3A8), gradually changing to greenish-yellow when mature, unchanging when bruised, shallowly depressed around the stipe at maturity. Pores small, 1–2 per mm, somewhat larger around the stipe, circular to angular; pore-surface concolorous with tubes. Stipe 20–45 × 2–6 mm, central, cylindrical or clavate, equal to slightly enlarged downwards, glabrous, dry or slightly viscid when wet, pale orange to pale red (5A3–7A3), pastel red (8A5–10A5), with very pale flush of pastel red (8A5–10A5) fibrous stripes. Stipe context white to pastel red (8A4–10A4), slightly darker when bruised, especially in the lower part. Basal mycelium white. Odour none. Taste mild.
Basidiospores [80/3/3] (7–)8–10.5(–11) ×(4–)4.5–5 μm, Q = (1.5–)1.8–2.2(–2.6), Qm = 2.0 ± 0.21, subfusiform and inequilateral in side view, oblong to ovoid in ventral view, smooth, yellowish to yellowish-brown in 5% KOH and yellow brown to dark brown in Melzer’s reagent, thin-walled. Basidia 1, 2, 4-spored 25–46 × 9–16 μm, clavate, yellowish-white to hyaline in 5% KOH; sterigmata 2–4.5 µm long. Pleurocystidia frequent, 38–66 × 11–15 μm, fusiform, thin-walled, yellowish-white to hyaline in 5% KOH. Cheilocystidia similar to pleurocystidia in shape and size. Hymenophoral trama composed of subparallel hyphae 5–11 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis an entangled trichodermium of erect hyphae 5–17 μm in diameter, branched, yellowish-white to hyaline in 5% KOH, dextrinoid in Melzer’s reagent; terminal cells cylindrical, clavate or nearly fusoid. Stipitipellis a layer of repent hyphae 4–23 μm in diameter, hyaline in 5% KOH. Caulocystidia infrequent. Clamp connections absent in all tissues.
Solitary or gregarious on soil under broadleaf forests dominated by Castanopsis spp. and Cyclobalanopsis spp. and mixed with other broadleaf trees, alt. 300–1200 m; May to July, currently only known from Guangdong Province.
China, Guangdong Province, Shaoguan City, Nangling National Nature Reserve, alt. 1200 m, 29 July 2017, M. Zhang (GDGM70342); Guangdong Province, Huizhou County, Xiangtoushan National Nature Reserve, alt. 400 m, 16 June 2016, J.P. Zou (GDGM46222); Guangdong Province, Huizhou City, Nankunshan Provincial Nature Reserve, alt. 700 m, 15 May 2013, M. Zhang (GDGM42822); Guangdong Province, Shaoguan City, Danxianshan National Nature Reserve, alt. 300 m, 3 June 2017, M. Zhang (GDGM46807), Same locality, 2 June 2017, M. Zhang (GDGM49404).
Aureoboletus solus looks like A. tenuis; however, the latter differs from the former in its viscid basidiomata, ixotrichodermial stipitipellis, composed of terminal hyphae with slightly swollen tips and larger basidiospores (10–)11–12 × 4–5 µm (
This species can be easily distinguished from others in Aureoboletus by its dry and small basidiomata, brown orange to reddish-brown pileus, light yellow to pastel yellow stipe, covered with fibrillose to tomentose squamules and smooth basidiospores 10–13 × 4–6.5 μm.
“velutipes” refers to the stipe, covered with fibrillose to tomentose squamules.
China, Guangdong Province, Huizhou City, Xiangtoushan National Nature Reserve, on soil under the broadleaf forest, dominated by Fagaceae trees, alt. 350 m, 2 April 2015, M. Zhang (holotype: GDGM44713).
Basidiomata small-sized. Pileus 2–4 cm wide, obtuse to convex when young, becoming broadly convex to plane at mature, fleshy, dry, covered with fibrillose to tomentose squamules, light yellow, light orange (4A4–6A4), brownish-orange (6C7–7C7), brown to reddish-brown (6D7–9D7), slightly fading to light orange to brownish-orange towards margin. Context 3–5 mm thick at stipe, firm and tough in youth, soft when matured, yellowish to white on the whole, more or less reddish-brown beneath the pileipellis, slightly changing to pastel red (7A4–9A4) when exposed. Tubes 3–5 mm deep, distinctly depressed around stipe, yellowish-white (2A2–4A2) when young, becoming pale yellow, greyish-yellow, pastel yellow to olive yellow (2A3–4A3, 1B3–2B3, 2A4–3A4, 2C6–3C6) in age, often with an olive tint, unchanging when bruised. Pores 0.5–0.8 mm in diam., mostly subangular, slightly elongated around stipe at maturity, smaller near pileus margin, concolorous with tubes. Stipe 30–60 × 5–10 mm, central, cylindrical or narrowly clavate, solid, equal to slightly enlarged downwards, covered with white, yellowish-white to yellowish-brown fibrillose to tomentose squamules, usually forming reticulation or longitudinally striate, light yellow to pastel yellow (2A4–4A4, 2A5–4A5), with white basal mycelium. Odour none. Taste mild.
Basidiospores [90/3/3] 10–13 × (4–)5–6(–6.5) μm, Q = (1.75–)1.8–2.2(–2.4), Qm = 2.08 ± 0.35, subfusiform and inequilateral in side view, oblong to ovoid in ventral view, smooth, yellowish to yellowish-brown in 5% KOH and yellow brown to dark brown in Melzer’s reagent, thin-walled. Basidia 25–30 × 9–13 μm, clavate, predominantly 4-spored but frequently also 2-spored, with sterigmata 2–3 µm long, yellowish-white to hyaline in 5% KOH, without basal clamps. Pleurocystidia 35–65 × 10–18 μm, fusiform, thin-walled. Cheilocystidia frequent, similar to pleurocystidia in shape and size. Hymenophoral trama composed of subparallel hyphae 6–10 μm broad, yellowish-white to hyaline in 5% KOH. Pileipellis a trichodermium of erect and often branched hyphae 4–17 μm in diameter, yellowish-white to hyaline in 5% KOH, dextrinoid in Melzer’s reagent; terminal cells 30–60 × 4–17 μm, cylindrical, clavate or nearly fusoid. Stipitipellis a layer of repent to suberect branching hyphae 3–15 μm in diameter, with swollen tips, terminal cells 30–70 × 11–21 μm, hyaline in 5% KOH. Clamp connections absent in all tissues.
Scattered on soil in subtropical forests, dominated by Fagaceae (Castanopsis spp., Lithocarpus spp. and Quercus spp., etc). Currently known from southern China.
China, Guangxi Province, Guilin City, Maoershan National Nature Reserve, alt. 1380 m, 1 July 2012, M. Zhang (GDGM42608); Jiangxi Province, Jinggangshan City, Jingganshan National Nature Reserve, alt. 1000 m, 21 June 2016, H. Huang (GDGM52409).
The obviously villose or fibrous squamulose stipe can distinguish it from other species in Aureoboletus. Aureoboletus catenarius, recently described from southwest China, is somewhat similar to A. velutipes with a dry and tomentose pileus, but A. catenarius has a cracked and light brown to reddish-brown pileus, faintly or finely fibrillose stipe and smaller basidiospores 7–9 × 3.5–5 μm (
Boletus miniatoaurantiacus C.S. Bi & Loh, in Bi, Loh & Zheng, Acta Bot. Yunn. 4(1): 60, 1982
Aureoboletus tomentosus G. Wu & Zhu L. Yang, in Wu, Li, Zhu, Zhao, Han, Cui, Li, Xu & Yang, Fungal Diversity 81: 51, 2016
In
Basidiomata small to medium-sized. Pileus 1.5–8 cm wide, hemispheric when young, becoming convex to nearly plane in age, fleshy, dry or viscid when wet, surface minutely tomentose or pulverous, slightly wrinkled, orange yellow, reddish-yellow, orange to reddish-orange (4A6–7A6, 4A7–7A7), commonly with a thin and slightly extended margin. Context 5–10 mm thick at centre, firm and tough in youth and, later, soft, white to yellowish-white, with more or less green tint at border contacting tubes, unchanging when exposed. Tube 3–10 mm deep, light orange to orange unchanging when bruised. Pores polygonal, 0.5–1.5 per mm, somewhat relatively larger and shallowly depressed around the stipe, orange to pale orange unchanging when bruised. Stipe 30–80 × 4–10 mm, central, solid, cylindrical or clavate, equal to slightly enlarged downwards, smooth to distinctly longitudinally streaks or broad reticulations, viscid in wet condition, concolorous with pileus. Stipe context concolorous with that of pileus, unchanging when exposed. Basal mycelium white to yellowish-white. Odour strong. Taste mild.
Basidiospores [90/3/3] (6.5–)7–10.5(–11) × (4–)4.5–5.5(–6) μm, Q = (1.42–)1.6–2.0(–2.3), Qm = 1.79 ± 0.18, ovoid and inequilateral in side view with an obtuse apex, ovoid in ventral view, smooth, yellowish to yellowish-brown in 5% KOH and yellow brown to dark brown in Melzer’s reagent, thin-walled. Basidia 18–35 (45) × 7–14 μm, 4-spored, rarely 1-, 2-, 3-spored, clavate, yellowish-white to hyaline in 5% KOH, sterigmata 2–3 μm. Cheilocystidia (21) 26–55 (61) × (6) 8–12 μm, fusiform to subclavate, thin-walled, contained with bright yellow pigments. Pleurocystidia similar to cheilocystidia in shape and size, thin-walled, yellowish-white to hyaline in 5% KOH. Hymenophoral trama composed of interwoven branched hyphae 6–15 μm wide, yellowish-white to hyaline in 5% KOH. Pileipellis an entangled trichodermium to ixotrichodermium of erect hyphae 4–18 μm in diameter, composed of yellow to bright yellow vacuolar pigmented filamentous hyphae, terminal cells cylindrical, clavate or nearly fusoid. Stipitipellis a tangled layer of repent to suberect branching hyphae 7–12 μm in diameter, hyaline in 5% KOH. Caulocystidia 25–75 × 12–18 μm, common, clavate, fusoid or fusoid ventricose and usually contain yellow to yellowish-brown substance in an early stage in 5% KOH. Stipe trama composed of parallel hyphae 4–18 μm wide. Clamp connections absent in all tissues.
Scattered on soil in tropical to subtropical forests dominated by Fagaceae (Castanopsis chinensis, C. fissa, Lithocarpus spp. and Quercus spp.). Currently known from southern and southwest China
China, Guangdong Province, Zhaoqing City, Dinghu Mountain, 6 September 1980, C.S. Bi et al. 677 (GDGM4677, holotype of B. miniatoaurantiacus); Same locality, 14 April 1981, C. Li (GDGM5071); 11 August 1981, C.S. Bi et al. 855 (GDGM4855); Fujian Province, Zhangping City, alt. 350 m, 2 September 2009, N.K. Zeng 664, 669 (FHMU424, 429); same locality, 27 July 2013, N.K. Zeng 1294 (FHMU848); 29 July 2013, N.K. Zeng 1323 (FHMU876); 1 August 2013, N.K. Zeng 1339 (FHMU891); Guangdong Province, Guangzhou City, Tianluhu Forest Park, alt. 200 m, 29 May 2015, M. Zhang (GDGM42855); Guangdong Province, Shaoguan City, Chebaling National Nature Reserve, alt. 300 m, 3 September 2013, M. Zhang & C.Q. Wang (GDGM43282); Guangdong Province, Huizhou City, Xiangtoushan National Nature Reserve, alt. 300 m, 7 July 2015, M. Zhang (GDGM44727); Jiangxi Province, Chongyi County, Yangling National Forest Park, alt. 280 m, 14 August 2015, M. Zhang (GDGM51694 and GDGM43439); same locality, 31 August 2016, H. Huang (GDGM52888); Same locality, 1 September 2016, M. Zhang (GDGM53350); Same locality, 2 September 2016, M. Zhang (GDGM53274); Same locality, 3 September 2016, M. Zhang (GDGM53501).
Aureoboletus miniatoaurantiacus, originally described as B. miniatoaurantiacus, is a rather common species in southern China and can be easily distinguished by its bright orange-yellow basidiomata, tomentose or pulverulent pileus surface, light orange to orange hymenophore unchanging when bruised and ovoid basidiospores. Based on a re-study of the type specimen and other collections quoted by Bi et al. in 1994, we found that the type specimen is composed of two small immature basidiomata, which are in a poor condition for morphological observation, but other voucher specimens fit well with the description of A. tomentosus. Thus, the newly described species A. tomentosus is, in fact, a synonym of A. miniatoaurantiacus, this conclusion also being supported by molecular data in this study (
1 | Pileus dry or slightly viscid when wet | 2 |
– | Pileus viscid | 13 |
2 | Basidiomata medium to larger (≥ 6 cm in diam.) | 3 |
– | Basidiomata smaller (< 6 cm in diam.) | 4 |
3 | Pileus 6–10 cm in diameter, greyish-orange to brownish-orange; stipe glabrous, greyish-yellow on the upper part to blond on the lower part; context unchanging when cut; basidiospores 9–11 × 4–5.5 µm | A. yunnanensis |
– | Pileus 6–15 cm in diameter, brownish-red to reddish-brown; context yellowish-white changing to yellowish-olivaceous when injured; hymenophore pale yellow to olivaceous yellow; stipe surface with longitudinal stripe, brownish-red to reddish-brown; basidiospores subglobose, 7–8 × 5.5–6 µm | A. clavatus |
4 | Stipe surface smooth or with small dots or splotches | 5 |
– | Stipe surface non-smooth, with reticula, longitudinal stripe, flocci or others | 11 |
5 | Basidiospores nodulose to verrucose, 12–15 × 8–11 µm; basidiomata small, golden brown to umber; stipe up to 7 cm long | A. shichianus |
– | Basidiospores surface smooth; other characters not as above | 6 |
6 | Hymenophore bright yellow to vivid yellow, unchanging when old | 7 |
– | Hymenophore pale yellow, light yellow, greenish-yellow to olive brown | 8 |
7 | Pileus greyish-rose to brownish-red, glabrous to slightly subtomentose; context pale yellow to light yellow unchanging when cut; stipe dark orange to yellow ochre, with distinct longitudinal streaks and furfuraceous scales; basidiospores 8–10.5 × 5–6 µm | A. nephrosporus |
– | Pileus reddish-brown to greyish-ruby, smooth to minutely velvet-subtomentose; context white to yellowish-white changing to greyish-red to greyish-rose when exposed; stipe smooth, concolorous with pileus; stipe context white to reddish-white gradually changing to greyish-red to greyish-rose when bruised; basidiospores 9–10.5 × 4.5–5 μm | A. griseorufescens |
8 | Pileus yellowish-white to reddish-white; context white, unchanging or slightly changing blue near the hymenium when exposed; tubes greyish-yellow to light yellow, unchanging when bruised; stipe context white to yellowish-white, slightly changing pale yellow when exposed; odour with radish scent; basidiospores 5–9 × 5–6 μm | A. raphanaceus |
– | Pileus coloured with brownish-red to reddish-brown tonalities | 9 |
9 | Pileipellis epithelium; basidiospores subfusoid, 7–9 × 3.5–5 μm | A. catenarius |
– | Pileipellis trichoderm | 10 |
10 | Basidiospores fusiform to ovoid, 8–10.5 × 4.5–5 μm | A. solus |
– | Basidiospores oblong to ovoid, 8.5–10.5 × 5–5.5 µm | A. rubellus |
11 | Stipe surface ornamented with distinctly reticulation, pileus surface covered with coarse tomentose, basidiospores (20–)22–27(–28) × 9–13 µm | A. mirabilis |
– | Stipe surface without reticulation or the reticulation inconspicuous | 12 |
12 | Stipe surface ornamented with distinctly longitudinally streaks or dotted scales; pileus surface orange yellow, reddish-yellow to reddish-orange, covered with tomentose; hymenophore light orange to orange; basidiospores 7–11 × 4.5–6 μm | A. miniatoaurantiacus |
– | Stipe surface covered with distinctly fibrillose to tomentose squamules; pileus surface brownish-orange to reddish-brown, covered with fibrillose to tomentose squamules; context yellowish-white changing to pastel red when exposed; basidiospores 10–13 × 4–6.5 μm | A. velutipes |
13 | Pileus margin with a gelatinised membranous veil | 14 |
– | Pileus margin without any membranous veil | 19 |
14 | Pileus surface distinctly reticulate, coarsely rugose, chestnut-brown to pale brown; stipe whitish; pleurocystidia covered with yellow substance on surface; basidiospores 9.5–13 × 4.5–5 µm | A. thibetanus |
– | Pileus glabrous or slightly rugose in central | 15 |
15 | Basidiospores smooth | 16 |
– | Basidiospores longitudinally costate, 12–16 × 9–12 µm | A. longicollis |
16 | Pileus brownish to brown; basidiospores 10–12.5 × 4.5–5 µm | A. viscidipes |
– | Pileus reddish-brown to violet brown | 17 |
17 | Basidiomata usually ≥ 2.5 cm; basidiospores 11–13.5 × 4.5–5.5 µm | A. tenuis |
– | Basidiomata usually < 2.5 cm | 18 |
18 | Basidiospores 8.5–10 × 4–4.5 µm | A. marroninus |
– | Basidiospores 10–13.5 × 4.5–5 µm | A. glutinosus |
19 | Pileus wrinkled, greyish-yellow to brownish-orange; taste salty; distribution in subalpine zone, ectomycorrhizal with Quercus spinose; basidiospores 15–21 × 5–6.5 μm | A. squercus-spinosae |
– | Pileus smooth, fibrillose to tomentose; the rest of the characters usually not as above | 20 |
20 | Basidiospores relatively broader, 7.5–10.5 × 5–6 μm, Qm < 2 | A. venustus |
– | Basidiospores relatively narrower, usually Qm ≥ 2 | 21 |
21 | Basidiospores comparatively larger, 15–16.5 × 4.5–5 μm | A. formosus |
– | Basidiospores comparatively smaller, commonly < 15 μm long | 22 |
22 | Basidiomata small to medium-sized (pileus usually < 5 cm). Pileus yellowish-brown or reddish-golden, subtomentose; stipe light brown to brownish-orange; basidiospores 9–11 × 4–5 μm | A. zangii |
– | Basidiomata medium to large (pileus usually > 5 cm) | 23 |
23 | Pileus violet brown to brownish-violet, glabrous to minutely velvet-subtomentose; stipe pastel red with a pale flush fibrous stripe; taste salty; basidiospores 10–14 × 4.5–5.5 μm | A. sinobadius |
– | Pileus reddish-brown to brownish-red, nearly glabrous; stipe reddish-orange to garnet brown with faintly longitudinal streaks; taste unknown, basidiospores 8.5–13 × 4.5–5.5 μm | A. duplicatoporus |
In the taxonomic circumscription of the genus Aureoboletus proposed by
The present study demonstrates that species of Aureoboletus are very diverse in China, especially in its southern areas. Common morphological characteristics and molecular data make Aureoboletus easily distinguishable from other existing genera in Boletaceae, but some variable morphological features make it difficult to recognise some species. Careful examination showed that several morphological characteristics are available to delimit these species in China. For example, the colour of the hymenophore and pattern of the pileus are important characteristics: A. glutinosus has a light yellow to olive yellow hymenophore and a coarse pileus with irregular reticulation; A. sinobadius has a vivid yellow hymenophore and a subtomentose to glabrous and viscid pileus; A. miniatoaurantiacus has a light orange to orange hymenophore and a tomentose to pulverous pileus; regarding the size of basidiomata, A. clavatus and A. yunnanensis have relatively larger basidiomata up to 10 cm in diameter, whereas A. glutinosus and A. marroninus have smaller basidiomata usually less than 2.5 cm in diameter. The colour of the pileus and the colour and odour of the context also help to identify species in the field. In contrast to macro-morphology, several micro-morphological features can also be used to discriminate species of Aureoboletus, such as the size and shape of basidiospores and the shape and inclusion of cystidia, pileipellis and stipitipellis seem to be rather constant amongst the different species.
In the present study, all selected samples of Aureoboletus formed a well-supported monophyletic group and eight major clades are proposed here, based on morphological characteristics and phylogenetic inference.
Clade I is characterised by the presence of a viscid pileus, a vivid yellow to greyish-yellow hymenophore that is unchanging when bruised, smooth basidiospores and ixotrichodermium pileipellis. In the present study, this group contains ten species, including the type species A. gentilis and the new species A. sinobadius. This clade is a rather homogeneous group in terms of morphology, which is consistent with the definition of Aureoboletus given by
Clade II is characterised by the presence of a dry (or slightly sticky when wet) pileus, a vivid yellow to olive yellow hymenophore that is unchanging when bruised, smooth basidiospores and trichodermium pileipellis. This clade includes six species, of which A. velutipes has distinctive morphological characteristics, such as a villous pileus and stipe, pale yellow to olive yellow hymenophore and swollen tips in terminal cells of the stipitipellis.
Clade III is well-characterised by the presence of a viscid pileus with well-developed yellowish to subhyaline veil remnant at the margin, greyish-yellow to olive yellow hymenophore, smooth to longitudinally costate basidiospores and ixotrichodermium pileipellis. Aureoboletus longicollis, originally described from Malaysia, is a well-defined species in this clade and is readily distinguished by its more viscid and larger basidioma, longer stipe and longitudinally costate basidiospores. A Chinese species, A. viscosus, shares similar traits with A. longicollis and the two species cannot be separated from each other in morphology. In this study, we did not have access to specimens of A. longicollis from Malaysia for morphological and phylogenetical study and it is not possible to make a taxonomic decision on whether A. viscosus is the same or a different species to A. longicollis without phylogenetic data. Thus, the name A. longicollis is temporarily used in this study and further studies with more materials are needed. The other species in this clade are characterised by smooth basidiospores and they can be distinguished from each other by their pileus colour and the size of basidiospores.
Clade IV contains the species A. auriflammeus and A. miniatoaurantiacus, which are mainly characterised by their bright orange yellow basidiomata, tomentose pileus surface and ovoid basidiospores. Species in this clade can be easily distinguished from others in this genus.
Clade V is characterised by the presence of a dry or somewhat tacky pileus, greyish-yellow to vivid yellow hymenophore changing to olive yellow when mature and oblong, ovoid to nephroid basidiospores. This clade contains five species, including the two species A. solus and A. raphanaceus described above.
Clade VI is composed of four distinct species, which have all been recently added to Aureoboletus, based on phylogenetic analyses (
Clade VII is currently formed by a single species, A. clavatus. The most striking characteristics are the large basidiomata with slightly viscid pileus, yellowish-white context staining yellowish-olivaceous when exposed, pale yellow to olivaceous-yellow hymenophore, subglobose basidiospores and the pileipellis composed of a turf of clavate hyphae. Besides the slightly viscid pileus, this species shares nearly none of the basic morphological traits of the genus Aureoboletus. However, phylogenetic analyses showed that it belongs to Aureoboletus and formed a separate branch.
Clade VIII is formed by a single species A. griseorufescens. Morphologically, A. griseorufescens is similar to those species in Clade I with a vivid yellow hymenophore and subviscid pileus; however, the most striking characteristic of A. griseorufescens is its white to yellowish-white context changing to greyish-red or greyish-rose when exposed. In the phylogenetic tree, A. griseorufescens formed the basal branch of Aureoboletus with highly-supported values, which showed that it might be an early divergent species from Aureoboletus.
Aureoboletus is a cosmopolitan genus, but most known species have relatively distinct habitats or regional locations. Currently, most of known Aureoboletus species are distributed in East Asia (mainly in China) and North America and intercontinentally-distributed species are infrequent. Two species A. projectellus and A. mirabilis, originally reported from North America, were examined in several studies and found to have disjunctive distributions in the North Temperate region from North America to Asia (China, Japan) and Europe (
Phylogenetic analyses based on 144 collections uncovered some useful information regarding the geography of Aureoboletus. Species in Clades III, V and VIII are found in Asia (China-Japan-Malaysia-Vietnam), representing subtropical-tropical Asia distributions. Compared with North America and Europe, China has the greatest number of Aureoboletus species and endemic species, especially in the subtropical-tropical region. Furthermore, many regions in China are under-sampled and more under-described indigenous Aureoboletus species will undoubtedly be discovered in the future. The high diversity of Aureoboletus species in China indicates that the subtropical-tropical region of China (or Asia) is the current species diversity centre of Aureoboletus.
In this study, some evolutionary patterns of morphological characteristics were also discovered. The traits of dry or viscid pileus surface and hymenophore colour appear to be relatively stable evolutionary characteristics and were wellsupported by monophyletic clades on the phylogenetic tree. The shape and surface ornamentation of basidiospores are not reliable characteristics for delimiting Aureoboletus, but are useful for species identification. Basidiospores ornamentation may have evolutionarily originated several times within Aureoboletus history. More morphological and molecular data are needed to understand this trait.
The authors are grateful to the editors and anonymous reviewers for their constructive comments and suggestions. Thanks are given to Mr. Hao Huang, Ting Li, Jun-Ping Zou, Zong-Ping Song (Guangdong Institute of Microbiology) and Yu Chen (Guangdong Xiangtoushan National Nature Reserve Administration) for their kind help in the fieldwork; to Dr. Chun-Ying Deng (Guizhou Academy of Sciences) and Dr. Chuan-Hua Li (Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences) for providing collections. This study was supported by the National Natural Science Foundation of China (Nos. 31700021, 31770014, 31670029), the Ministry of Science and Technology of the People’s Republic of China (2013FY111500), the Ministry of Ecology and Environment (2019HB2096001006) and the GDAS’ Special Project of Science and Technology Development (2019GDASYL-0104009).