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Research Article
Two new species of Hymenochaetaceae on Dracaena cambodiana from tropical China
expand article infoPing Du, Tian-Xu Cao, Ying-Da Wu§, Meng Zhou|, Zhan-Bo Liu|
‡ Yangtze Normal University, Chongqing, China
§ China Fire and Rescue Institute, Beijing, China
| Beijing Forestry University, Beijing, China
Open Access

Abstract

Two new wood-rotting fungi in the family Hymenochaetaceae, Fulvifomes dracaenicola sp. nov. and Hymenochaete dracaenicola sp. nov., are described and illustrated from tropical China based on morphological characteristics and molecular data. It is worth to mention that both of them grow on Dracaena cambodiana which is a kind of angiosperm tree distributed in tropical regions. F. dracaenicola is characterised by perennial, pileate, triquetrous basidioma with yellowish brown fresh pores which becoming honey yellow with silk sheening upon drying, a dimitic hyphal system in trama and monomitic in context, and subglobose basidiospores measuring 4.8–5 × 4–4.1 μm. H. dracaenicola is characterised by annual, resupinate basidioma with a clay buff hymenophore, a dimitic hyphal system, absence of tomentum and cortex, presence of subulate setae, absence of cystidia, presence of cystidioles and simple hyphidia, and oblong ellipsoid basidiospores measuring 5.2–5.8 × 2.5–2.8 µm. The phylogenetic analyses based on ITS + nLSU rDNA sequences confirm the placement of two new species respectively in Fulvifomes and Hymenochaete. Phylogenetically closely related species to the two new species are discussed.

Keywords

Phylogenetic analysis, taxonomy, wood-rotting fungi

Introduction

Fulvifomes Murrill (Hymenochaetaceae, Hymenochaetales) was erected in 1914 and typified by F. robiniae (Murrill) Murrill (Murrill 1914). Wagner and Fischer (2002) thought that Fulvifomes comprises species with a dimitic hyphal system, absence of setae, and yellowish, thick-walled basidiospores. Hattori et al. (2014) provided a key to worldwide species of Fulvifomes and other species possibly belonging to Fulvifomes. Zhou (2014) treated Aurificaria D.A. Reid as a taxonomic synonym of Fulvifomes and transferred Aurificaria indica (Massee) D.A. Reid to Fulvifomes. However, Fulvifomes indicus (Massee) L.W. Zhou has a monomitic hyphal system, but he thought that the hyphal system might be not a stable character at the generic level within Hymenochaetaceae. Salvador-Montoya et al. (2018) redefined Fulvifomes and thought Fulvifomes should encompass species with a monomitic hyphal system in the context, a dimitic hyphal system in the trama. We agree with Zhou and Salvador-Montoya et al., and consider the genus Fulvifomes has a monomitic or dimitic hyphal system.

Hymenochaete Lév. (Hymenochaetaceae, Hymenochaetales) was erected in 1846 and typified by H. rubiginosa (Dicks.) Lév. (Léveillé 1846). Léger (1998) wrote a world monograph of Hymenochaete and provided a key of the genus. The genus comprises more than 120 species around the world (He and Dai 2012). Hymenochaete is characterised by annual to perennial, resupinate, effused-reflexed to pileate basidioma with smooth, tuberculate, lamellate, poroid or hydnoid hymenophores; a monomitic or dimitic hyphal system; presence of setae, and hyaline, thin-walled, narrowly cylindrical to globose basidiospores (Léger 1998; Parmasto 2001; He and Dai 2012).

During investigations on the diversity of wood-rotting fungi from China, five unknown specimens were collected from Hainan Province, and their morphology corresponds to the concepts of Fulvifomes and Hymenochaete. To confirm their affinity, phylogenetic analyses based on the ITS and nLSU rDNA sequences were carried out. Both morphological characteristics and molecular evidence demonstrated these five specimens represent two new species of Hymenochaetaceae, which we describe in the present paper.

Materials and methods

Morphological studies

Macro-morphological descriptions were based on field notes and dry herbarium specimens. Microscopic measurements and drawings were made from slide preparations of dried tissues stained with Cotton Blue and Melzer’s reagent following Dai (2010). Pores were measured by subjectively choosing as straight a line of pores as possible and measuring how many fit per mm. The following abbreviations are used: KOH = 5% potassium hydroxide, CB = Cotton Blue, CB– = acyanophilous, IKI = Melzer’s reagent, IKI– = neither amyloid nor dextrinoid, L = mean spore length (arithmetic average of all spores), W = mean spore width (arithmetic average of all spores), Q = variation in the L/W ratios between specimens studied, and n (a/b) = number of spores (a) measured from given number of specimens (b). In presenting spore size variation, 5% of measurements were excluded from each end of the range and this value is given in parentheses. Special color terms follow Anonymous (1969) and Petersen (1996). Herbarium abbreviations follow Thiers (2018). The studied specimens were deposited at the herbarium of the Institute of Microbiology, Beijing Forestry University (BJFC).

Molecular studies and phylogenetic analysis

A CTAB rapid plant genome extraction kit (Aidlab Biotechnologies Co., Ltd., Beijing, China) was used to extract total genomic DNA from dried specimens following the manufacturer’s instructions with some modifications (Cui et al. 2019; Shen et al. 2019). ITS regions were amplified with primers ITS4 and ITS5 (White et al. 1990), and the nLSU with primers LR0R and LR7. The polymerase chain reaction (PCR) procedure for ITS was as follows: initial denaturation at 95 °C for 3 min, followed by 35 cycles at 94 °C for 40 s, 58 °C for 45 s, and 72 °C for 1 min, and a final extension of 72 °C for 10 min. The PCR procedure for nLSU was as follows: initial denaturation at 94 °C for 1 min, followed by 35 cycles at 94 °C for 30 s, 48 °C for 1 min, and 72 °C for 1.5 min, and a final extension of 72 °C for 10 min (Chen et al. 2015). The PCR products were purified and sequenced in the Beijing Genomics Institute, China, with the same primers used in the PCR reactions.

Phylogenetic trees were constructed using ITS and nLSU rDNA sequences, and phylogenetic analyses were computed with maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) methods. Sequences of Fulvifomes were adopted mainly from ITS + nLSU tree topologies established by Liu et al. (2020). Sequences of Hymenochaete were adopted mainly from ITS + nLSU tree topologies established by He et al. (2017) and Rossi et al. (2020). New sequences generated in this study, along with reference sequences retrieved from GenBank (Table 1 and Table 2), were aligned by MAFFT 6 (Katoh and Toh 2008; http://mafft.cbrc.jp/alignment/server/) using the “G-INS-i” strategy and manually adjusted in BioEdit (Hall 1999). The data matrix was edited in Mesquite v3.04 software (Maddison and Maddison 2010). The sequence alignment was deposited at TreeBase (Fulvifomes, http://purl.org/phylo/treebase/phylows/study/TB2:S27995; submission ID 27995) and (Hymenochaete, http://purl.org/phylo/treebase/phylows/study/TB2:S27696; submission ID 27696). Sequences of Phellinus laevigatus (P. Karst.) Bourdot & Galzin and P. populicola Niemelä obtained from GenBank were used as outgroups of Fulvifomes to root trees following Ji et al. (2017) in the ITS + nLSU analysis. Sequences of Hydnoporia tabacina (Sowerby) Spirin, Miettinen & K.H. Larss. obtained from GenBank were used as outgroups of Hymenochaete to root trees following He et al. (2017) in the ITS + nLSU analysis.

Table 1.

A list of species, specimens and GenBank accession numbers of sequences used in the phylogenetic analysis of Fulvifomes.

Taxa Voucher ITS LSU
Fomitiporella caryophylli CBS 448.76 AY558611 AY059021
Fulvifomes centroamericanus JV 0611/III KX960763 KX960764
F. centroamericanus JV 0611/8P KX960757
F. dracaenicola Dai 22093 MW559799 MW559804
F. dracaenicola Dai 22097 MW559800 MW559805
F. fastuosus LWZ 20140731-13 KR905674 KR905668
F. fastuosus LWZ 20140718-29 KR905673
F. fastuosus Dai 18292 MH390411 MH390381
F. grenadensis JV 1212/2J KX960756
F. grenadensis JV 1607/66 KX960758
F. hainanensis Dai 11573 KC879263 JX866779
F. halophilus XG 4 JX104705 JX104752
F. halophilus JV 1502/4 MH390427 MH390392
F. imbricatus LWZ 20140728-16 KR905677 KR905670
F. imbricatus LWZ 20140729-25 KR905678
F. imbricatus LWZ 20140729-26 KR905679 KR905671
F. indicus Yuan 5932 KC879261 JX866777
F. indicus O 25034 KC879262 KC879259
F. krugiodendri JV 0904/1 KX960762 KX960765
F. krugiodendri JV 0312/24.10J KX960760 KX960766
F. krugiodendri JV 1008/21 KX960761 KX960767
F. merrillii JX484013
F. nilgheriensis URM 3028 MH390431 MH390384
F. nilgheriensis PPT152 MH048095 MH048085
F. rimosus M 2392655 MH628255 MH628017
F. robiniae CBS 211.36 AY558646 AF411825
F. robiniae EF088656
F. siamensis XG 2 JX104709 JX104756
F. siamensis Dai 18309 MH390434 MH390389
F. sp. PM 950703-1 EU035311
F. squamosus CS385 MF479268 MF479265
F. squamosus CS444 MF479269 MF479264
F. submerrillii Dai 17911 MH390405 MH390371
F. submerrillii Dai 17917 MH390406 MH390372
F. thailandicus LWZ 20140731-1 KR905672 KR905665
F. xylocarpicola MU 8 JX104676 JX104723
Inocutis rheades AF237731
Inonotus hispidus CBS 388.61 AY558602
I. lloydii Dai 10809 MH390428 MH390378
I. lloydii Dai 9642 MH390429 MH390379
I. lloydii Dai 11978 MH390430 MH390380
I. porrectus CBS 296.56 AY558603 AY059051
I. rigidus Dai 17496 MH390432 MH390398
I. rigidus Dai 17507 MH390433 MH390399
Phellinotus neoaridus URM 80362 KM211294 KM211286
P. piptadeniae URM 80766 KM211293 KM211285
Phellinus laevigatus CBS 122.40 MH856059 MH867554
P. populicola CBS 638.75 MH860960 MH872729
Phylloporia crataegi Dai 18133 MH151191 MH165865
P. ribis CBS 579.50 MH856765 MN240818
Table 2.

A list of species, specimens and GenBank accession numbers of sequences used in the phylogenetic analysis of Hymenochaete.

Taxa Voucher ITS LSU
Hydnoporia tabacina He 390 JQ279610 JQ279625
Hymenochaete acerosa He 338 JQ279543 JQ279657
H. adusta He 207 JQ279523 KU975497
H. angustispora Dai 17045 MF370592 MF370598
H. angustispora Dai 17049 MF370593 MF370599
H. anomala He 592 JQ279566 JQ279650
H. asetosa Dai 10756 JQ279559 JQ279642
H. attenuata He 28 JQ279526 JQ279633
H. bambusicola He 4116 KY425674 KY425681
H. berteroi He 1488 KU975459 KU975498
H. biformisetosa He 1445 KF908247 KU975499
H. boddingii MEH 66068 MN030343 MN030345
H. boddingii MEH 69996 MN030341 MN030347
H. boddingii MEH 66150 MN030344 MN030344
H. borbonica CBS 731.86 MH862026 MH873716
H. cana He 1305 KF438169 KF438172
H. cinnamomea He 755 JQ279548 JQ279658
H. colliculosa Dai 16427 MF370595 MF370602
H. colliculosa Dai 16428 MF370596 MF370603
H. colliculosa Dai 16429 MF370597 MF370604
H. conchata MEH 70144 MF373838
H. contiformis He 1166 KU975461 KU975501
H. cruenta He 766 JQ279595 JQ279681
H. cyclolamellata Cui 7393 JQ279513 JQ279629
H. damicornis URM 84261 KC348466
H. damicornis URM 84263 KC348467
H. denticulata He 1271 KF438171 KF438174
H. dracaenicola Dai 22090 MW559797 MW559802
H. dracaenicola Dai 22096 MW559798 MW559803
H. duportii AFTOL ID666 DQ404386 AY635770
H. epichlora He 525 JQ279549 JQ279659
H. floridea He 536 JQ279597 JQ279683
H. fuliginosa He 1188 KU975465 KU975506
H. fulva He 640 JQ279565 JQ279648
H. globispora He 911 KU975508
H. huangshanensis He 432 JQ279533 JQ279671
H. hydnoides He 245 JQ279590 JQ279680
H. innexa He 555 JQ279584 JQ279674
H. legeri He 960 KU975469 KU975511
H. longispora He 217 JQ279537 KU975514
H. luteobadia He 8 JQ279569 KU975515
H. macrochloae ARAN-Fungi 7079 MF990738 MF990743
H. megaspora He 302 JQ279553 JQ279660
H. minor He 933 JQ279555 JQ279654
H. minuscula He 253 JQ279546 KU975516
H. murina He 569 JQ716406 JQ716412
H. muroiana He 405 JQ279542 KU975517
H. nanospora He 475 JQ279531 JQ279672
H. ochromarginata He 47 JQ279579 JQ279666
H. odontoides Dai 11635 JQ279563 JQ279647
H. orientalis He 4601 KY425677 KY425685
H. parmastoi He 867 JQ780063 KU975518
H. paucisetigera Cui 7845 JQ279560 JQ279644
H. quercicola He 373 KU975474 KU975521
H. rhabarbarina He 280 JQ279574 KY425688
H. rheicolor Cui 8317 JQ279529
H. rhododendricola He 389 JQ279577 JQ279653
H. rubiginosa He 1049 JQ716407 JQ279667
H. rufomarginata He 1489 KU975477 KU975524
H. separabilis He 460 JQ279572 JQ279655
H. setipora Cui 6301 JQ279515 JQ279639
H. sharmae CAL 1535 KY929017 KY929018
H. sharmae 66088 MK588753 MK588836
H. spathulata He 685 JQ279591 KU975529
H. sphaericola He 303 JQ279599 JQ279684
H. sphaerospora He 715 JQ279594 KU975531
H. subferruginea Cui 8122 JQ279521
H. subferruginea He 1598 KU975481
H. tasmanica He 449 JQ279582 JQ279663
H. tongbiguanensis He 1552 KF908248 KU975532
H. tenuis He 779 JQ279538 JQ279641
H. tropica He 574 JQ279587 JQ279675
H. ulmicola He 864 JQ780065 KU975534
H. unicolor He 468a JQ279551 JQ279662
H. verruculosa Dai 17047 MF370600
H. verruculosa Dai 17052 MF370594 MF370601
H. villosa He 537 JQ279528 JQ279634
H. xerantica Cui 9209 JQ279519 JQ279635
H. yunnanensis He 1447 KU975486 KU975538

Maximum parsimony analysis was applied to the ITS + nLSU dataset sequences. Approaches to phylogenetic analysis followed Song et al. (2016), and the tree construction procedure was computed in PAUP* version 4.0b10 (Swofford 2002). All characters were equally weighted and gaps were treated as missing data. Trees were inferred using the heuristic search option with tree bisection and reconnection (TBR) branch swapping and 1000 random sequence additions maxtrees were set to 5000, branches of zero length were collapsed, and all parsimonious trees were saved. Clade robustness was assessed using a bootstrap (BT) analysis with 1000 replicates (Felsenstein 1985). Descriptive tree statistics tree length (TL), Consistency Index (CI), Retention Index (RI), Rescaled Consistency index (RC), and Homoplasy Index (HI) were calculated for each maximum parsimonious tree (MPT) generated. Sequences were also analyzed using maximum likelihood (ML) with RAxML-HPC through the CIPRES Science Gateway (Miller et al. 2009; http://www.phylo.org). Branch support for ML analysis was determined by 1000 bootstrap replicates.

MrModeltest 2.3 (Posada and Crandall 1998; Nylander 2004) was used to determine the best-fit evolution model for the combined dataset for Bayesian Inference (BI). BI was performed using MrBayes v. 3.2.7a (Ronquist and Huelsenbeck 2003) with four simultaneous independent chains for two datasets, performing 3 million generations (Fulvifomes) and 5 million generations (Hymenochaete) until the split deviation frequency value < 0.01, and sampled every 1000th generation. The first 25% sampled trees were discarded as burn-in, while the remaining ones were used to calculate Bayesian posterior probabilities (BPP) of the clades.

Branches that received bootstrap support for maximum likelihood (BS), maximum parsimony (BP), and Bayesian posterior probabilities (BPP) greater than 70% (BS), 50% (BP) and 0.95 (BPP) were considered as significantly supported, respectively. FigTree v1.4.2 (Rambaut 2012) was used to visualize the resulting tree.

Results

Phylogeny results

Fulvifomes

The combined ITS + nLSU dataset included sequences from 50 specimens representing 31 species (Table 1). The dataset had an aligned length of 1693 characters, of which 1013 (60%) were constant, 186 (11%) were variable but parsimony-uninformative, and 494 (29%) were parsimony-informative. MP analysis yielded two equally parsimonious trees (TL = 1841, CI = 0.546, RI = 0.712, RC = 0.389, HI = 0.454). The best model-fi for the ITS + nLSU dataset estimated and applied in the Bayesian analysis was GTR+I+G. Bayesian analysis and ML analysis resulted in a similar topology to the MP analysis, with an average standard deviation of split frequencies of 0.004578 (BI).

The phylogeny (Fig. 1) inferred from the ITS and nLSU sequences demonstrated that the new species Fulvifomes dracaenicola nested in the Fulvifomes clade. Moreover, two specimens of F. dracaenicola form a lineage with strong support (100% BP, 100% BS, 1.00 BPP, Fig. 1).

Figure 1. 

Phylogeny of Fulvifomes and related species by MP analysis based on combined ITS and nLSU rDNA sequences. Branches are labelled with maximum likelihood bootstrap > 70%, parsimony bootstrap proportions > 50%, and Bayesian posterior probabilities > 0.95, respectively. New species is in bold.

Hymenochaete

The combined ITS + nLSU dataset included sequences from 79 specimens representing 69 species (Table 2). The dataset had an aligned length of 2249 characters, of which 1486 (66%) were constant, 248 (11%) were variable but parsimony-uninformative, and 515 (23%) were parsimony-informative. MP analysis yielded 48 equally parsimonious trees (TL = 3261, CI = 0.365, RI = 0.619, RC = 0.226, HI = 0.635). The best model for the ITS + nLSU dataset estimated and applied in the Bayesian analysis was GTR+I+G. Bayesian analysis and MP analysis resulted in a similar topology to the ML analysis, with an average standard deviation of split frequencies of 0.009996 (BI).

The phylogeny (Fig. 2) inferred from the ITS and nLSU sequences demonstrated that the new species Hymenochaete dracaenicola clustered in the Hymenochaete clade and two specimens of H. dracaenicola form a lineage with strong support (100% BS, 100% BP, 1.00 BPP, Fig. 2).

Figure 2. 

Phylogeny of Hymenochaete and related species by ML analysis based on combined ITS and nLSU rDNA sequences. Branches are labelled with maximum likelihood bootstrap > 70%, parsimony bootstrap proportions > 50%, and Bayesian posterior probabilities > 0.95, respectively. New species is in bold.

Taxonomy

Fulvifomes dracaenicola Z.B. Liu & Y.C. Dai, sp. nov.

MycoBank No: 838682
Figs 3, 4

Diagnosis

Fulvifomes dracaenicola is characterised by perennial, pileate, triquetrous basidioma with yellowish brown fresh pores which becoming honey yellow with silk sheening upon drying, a dimitic hyphal system in trama and monomitic in context, subglobose basidiospores measuring 4.8–5 × 4–4.1 μm.

Figure 3. 

A basidiocarp of Fulvifomes dracaenicola (Holotype, Dai 22097). Scale bar: 1.0 cm. Photo by: Yu-Cheng Dai.

Figure 4. 

Microscopic structures of Fulvifomes dracaenicola (Holotype, Dai 22097) a basidiospores b hyphae of context c hyphae of the tubes. Drawings by: Meng Zhou.

Holotype

China. Hainan Province, Sanya, Daxiaodongtian Park, N18.299, E109.172, on living tree of Dracaena cambodiana, 15.XI.2020, Dai 22097 (BJFC 035989).

Etymology

Dracaenicola (Lat.): referring to the species growing on Dracaena cambodiana.

Fruiting body

Basidioma perennial, pileate, without odor or taste and woody hard when fresh, light in weight when dry. Pilei triquetrous, projecting up to 2.5 cm, 2.3 cm wide and 2.6 cm thick at base. Pileal surface yellowish brown to grayish brown when fresh, vinaceous brown when dry, encrusted, glabrous, zonate, uncracked, margin olivaceous brown. Pore surface yellowish brown when fresh, honey yellow with silk sheening when dry; sterile margin indistinct; pores circular, 5–7 per mm; dissepiments thin, entire. Context cinnamon buff to fawn, corky, often darker near the pileus surface, up to 1.4 cm thick, with a distinct crust (black line) near pileus surface at the basal area, partly with additional crust (black line) within context or above tubes. Tubes cinnamon buff to cinnamon, woody hard, up to 1.2 cm thick, tube layers distinctly stratified, individual tube layer up to 0.5 cm long.

Hyphal structure

Hyphal system dimitic in trama, monomitic in context; generative hyphae simple septate; tissues darkening but otherwise unchanged in KOH.

Context

Generative hyphae apricot-orange to brownish-orange, thick-walled with a wide lumen, simple septate, unbranched, regularly arranged, 4.5–6 µm in diam.

Trama of the tubes

Generative hyphae hyaline, thick-walled, simple septate, occasionally branched, 2–2.5 mm in diam; skeletal hyphae apricot-orange to brownish-orange, thick-walled to subsolid, unbranched, loosely interwoven, 3.5–4 mm in diam. Setae or setal hyphae absent; hymenium collapsed in the studied material, basidia and basidioles not seen.

Spores

Basidiospores subglobose with an apiculus, yellowish brown, thick-walled, smooth, IKI–, CB–, occasionally collapsed when mature, 4.8–5(–5.5) × 4–4.1 μm, L = 5.02 μm, W = 4.04 μm, Q = 1.22–1.25 (n = 90/3).

Additional specimens (paratypes) examined

China. Hainan Province, Sanya, Daxiaodongtian Park, N18.299, E109.172, on rotten wood of living Dracaena cambodiana, 15.XI.2020, Dai 22093 (BJFC 035986), Dai 22095 (BJFC 035987).

Hymenochaete dracaenicola Z.B. Liu & Y.C. Dai, sp. nov.

MycoBank No: 838683
Figs 5, 6

Diagnosis

Hymenochaete dracaenicola is characterised by annual, resupinate basidioma with a clay buff hymenophore, a dimitic hyphal system, absence of tomentum and cortex, subulate setae present in hyphal layer, absence of cystidia, presence of cystidioles and simple hyphidia, and oblong ellipsoid basidiospores measuring 5.2–5.8 × 2.5–2.8 µm.

Figure 5. 

A basidiocarp of Hymenochaete dracaenicola (Holotype, Dai 22090). Scale bar: 1.0 cm. Photo by: Zhan-Bo Liu.

Figure 6. 

Microscopic structures of Hymenochaete dracaenicola (Holotype, Dai 22090) a basidiospores b basidia and basidioles c cystidioles d hyphidia e setae f Hyphae from hyphal layer. Drawings by: Meng Zhou.

Holotype

China. Hainan Province, Sanya, Daxiaodongtian Park, N18.299, E109.172, on dead tree of Dracaena cambodiana, 15.XI.2020, Dai 22090 (BJFC 035983).

Etymology

Dracaenicola (Lat.): referring to the species s growing on Dracaena cambodiana.

Fruiting body

Basidioma annual, resupinate, adnate, not separable from substrate, hard corky, up to 7.5 cm long, 2 cm wide, and less than 0.1 mm thick at center. Hymenophore surface smooth or locally verruculose, clay buff, with some scattered crevices; margin cinnamon buff, up to 0.4 mm.

Hyphal structure

Hyphal system dimitic; generative hyphae infrequent, simple septate; skeletal hyphae dominant; tissues darkening but otherwise unchanged in KOH.

Subiculum

Tomentum and cortex absent; hyphal layer present. Generative hyphae infrequent, hyaline, thick-walled, simple septate, often branched, 1–2 µm in diam. Skeletal hyphae cinnamon to orange brown, thick-walled to subsolid, rarely branched, interwoven, 1.5–2.5 µm in diam.

Hymenium

Hyphae similar to those in hyphal layer. Setal layer present, thickening with age, with one to several rows of overlapping setae. Setae numerous, subulate with blunt to acute tips, orange brown to reddish brown, smooth, occasionally with a hyphal sheath, distinctly thick-walled, 30–57 × 6–10 µm, embedded or projecting up to 35 µm beyond the hymenium. Cystidia absent; cystidioles present, fusoid, hyaline, thin-walled, basally swollen, with a sharp or often hyphoid neck, 10–17 × 2.5–4 μm; Simple hyphidia present, scattered, thick-walled, 15–36 × 2–3.5 µm. Basidia subclavate to subcylindrical, with walls thickening toward the base, with four sterigmata and a basal simple septum, 17–23(–25) × 3.5–5 µm; basidioles similar to basidia but smaller.

Spores

Basidiospores oblong ellipsoid with an apiculus, hyaline, thin-walled, smooth, IKI–, CB–, occasionally bearing a guttule, (5–)5.2–5.8(–6.1) × 2.5–2.8 µm, L = 5.6 µm, W = 2.68 µm, Q = 2.03–2.15 (n = 60/2).

Additional specimen (paratype) examined

China. China. Hainan Province, Sanya, Daxiaodongtian Park, N18.299, E109.172, on fallen branch of Dracaena cambodiana, 15.XI.2020, Dai 22096 (BJFC 035988).

Discussion

Fulvifomes dracaenicola and Hymenochaete dracaenicola were found in tropical regions of China. It is interesting that both species growing on Dracaena cambodiana.

Morphologically, Fulvifomes dracaenicola (5–7 per mm) shares similar pores with F. kawakamii (M.J. Larsen, Lombard & Hodges) T. Wagner & M. Fisch. (5–7 per mm, Larsen et al. 1985), F. robiniae (5–6 per mm, Salvador-Montoya et al. 2018), F. swieteniae Murrill (5–7 per mm, Hattori et al. 2014) and F. thailandicus L.W. Zhou (6–7 per mm, Zhou 2015). F. dracaenicola and F. kawakamii share perennial, pileate basidioma, but basidioma of F. dracaenicola is solitary and glabrous, while basidioma of F. kawakamii is imbricate and nodulose. In addition, basidioma of F. kawakamii is much bigger (30–40 × 10–20 × 5–10 cm, Larsen et al. 1985) than that of F. dracaenicola. And basidiospores of F. dracaenicola are bigger than that of F. kawakamii (4.8–5 × 4–4.1 µm vs. 4.5 × 3.5 µm, Larsen et al. 1985). F. dracaenicola and F. robiniae share perennial, triquetrous and solitary basidioma, a monomitic hyphal system in context and dimitic in trama, however, F. robiniae can be distinguished from F. dracaenicola by its bigger basidiospores (5.5–6 × 4–5.5 µm vs. 4.8–5 × 4–4.1 µm). In addition, F. dracaenicola has a distinct crust (black line) on the pileal surface, but the crust (black line) is absent in F. robiniae (Gilbertson and Ryvarden 1987). F. dracaenicola resembles F. swieteniae by perennial, glabrous basidioma, a dimitic hyphal system in trama, however, basidioma of F. swieteniae is ungulate and pileal surface of F. swieteniae is azonate, while basidioma of F. dracaenicola is triquetrous and its pileal surface is zonate. And F. dracaenicola can be also distinguished from F. swieteniae by its wider basidiospores (4–4.1 µm vs. 3–4 µm, Salvador-Montoya et al. 2018). F. dracaenicola is similar to F. thailandicus by sharing perennial, solitary basidioma, but F. thailandicus can be distinguished from F. dracaenicola by a dimitic hyphal system in context, and its bigger basidiospores (5–5.8 × 4.1–4.8 µm vs. 4.8–5 × 4–4.1 µm, Zhou 2015).

Two specimens of Fulvifomes dracaenicola form a lineage with strong support (100% BP, 100% BS, 1.00 BPP, Fig. 1) in our phylogeny. F. dracaenicola is closely related to F. siamensis T. Hatt. et al. (98% BP, 99% BS, 1.00 BPP, Fig. 1) and both species share perennial, pileate basidioma, a dimitic hyphal system in trama and monomitic in context, and occurring in tropical Asia. Morphologically they can be easily differentiated by the presence of crust on the pileus surface. F. dracaenicola has a distinct crust (black line) on the pileus surface and partly with additional crust (black line) within context or above tubes, but the crust (black line) is absent in. F. siamensis (Hattori et al. 2014). Besides, F. siamensis has applanate pilei pores 7–8 per mm, thin- to thick-walled contextual generative hyphae 2–8 μm wide, and basidiospore 4–5 μm wide (Hattori et al. 2014), while F. dracaenicola has triquetrous pilei, pores 5–7 per mm, thick-walled contextual generative hyphae 4.5–6 μm wide, and basidiospore 4–4.1 μm wide. In addition, F. siamensis grows on Xylocarpus granatum in mangrove while F. dracaenicola grows on Dracaena cambodiana in terrestrial ecosystem.

Morphologically, to avoid redescribing the existed species, we review the monograph by Léger (1998) and compare Hymenochaete dracaenicola with all the species in the monograph. H. dracaenicola belongs to the section “FULTOCHAETE” and is similar to H. epichlora (Berk. & M.A. Curtis) Cooke. Both species share resupinate and adnate basidioma, absence of tomentum and cortex, similar setae (30–57 × 6–10 µm vs. 30–60 × 5.5–9 µm in H. epichlora, Cooke 1880), but H. dracaenicola has a dimitic hyphal system, while H. epichlora has a monomitic or subdimitic hyphal system and smaller basidiospores (5.2–5.8 × 2.5–2.8 µm vs. 3.5–5 × 1.8–2.5 µm, Cooke 1880). Besides, H. dracaenicola has simple hyphidia in hymenium, but hyphidia are absent in H. epichlora (Cooke 1880).Phylogenetically, two specimens of Hymenochaete dracaenicola form a lineage with strong support (100% BP, 100% BS, 1.00 BPP, Fig. 2). H. dracaenicola clusters together with H. borbonica J.C. Léger & Lanq., H. angustispora S.H. He & Y.C. Dai and H. tenuis Peck with strong support (100% BS, 98% BP, 1.00 BPP, Fig. 2). Morphologically, setae in H. dracaenicola are shorter than in H. borbonica (30–57 µm vs. 60–70 µm in H. borbonica). In addition, basidiospores of H. dracaenicola are oblong ellipsoid while they are suballantoid in H. borbonica (5–6 × 2 µm, Léger and Lanquetin 1987). H. angustispora is different from H. dracaenicola by a monomitic hyphal system and narrowly cylindrical to allantoid basidiospores (5–7 × 1.8–2.2 µm, He et al. 2017). H. tenuis can be distinguished from H. dracaenicola through its smaller basidiospores (4.5–5.5 × 2–2.5 µm vs. 5.2–5.8 × 2.5–2.8 µm) and a monomitic hyphal system (Peck 1887).

Acknowledgements

The research is supported by the National Natural Science Foundation of China (Project No. 31900019).

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