Phylogeny and diversity of Haploporus (Polyporaceae, Basidiomycota)

Meng Zhou; Li Wang; Tom W. May; Josef Vlasák; Jia-Jia Chen; Yu-Cheng Dai

doi:10.3897/mycokeys.54.34362

Abstract

Four species of Haploporus, H. angustisporus, H. crassus, H. gilbertsonii and H. microsporus are described as new and H. pirongia is proposed as a new combination, based on morphological characteristics and molecular phylogenetic analyses inferred from internal transcribed spacer (ITS) and large subunit nuclear ribosomal RNA gene (nLSU) sequences. Haploporus angustisporus, H. crassus and H. microsporus occur in China, H. gilbertsonii occurs in the USA, and the distribution of H. pirongia is extended from New Zealand to Australia. Haploporus angustisporus is characterized by the distinct narrow oblong basidiospores measuring 10.5–13.5 × 3.9–5 µm. Haploporus crassus is characterized by the presence of ventricose cystidioles occasionally with a simple septum, dissepimental hyphae usually with a simple septum, unique thick-walled basidia and distinctly wide oblong basidiospores measuring 13.5–16.5 × 7.5–9.5 µm. Haploporus gilbertsonii is characterized by its large pores (2–3 per mm), a dimitic hyphal structure with non-dextrinoid skeletal hyphae and wide oblong basidiospores measuring 12–15 × 6–8 µm. Haploporus microsporus is characterized by distinctly small pores (7–9 per mm), the presence of dendrohyphidia, and distinctly small ellipsoid basidiospores measuring 5.3–6.7 × 3–4.1 µm. Haploporus pirongia is proposed as a new combination. Haploporus amarus is shown to be a synonym of H. odorus and Pachykytospora wasseri is considered a synonym of H. subtrameteus.

Keywords

Polyporales, taxonomy, wood-inhabiting fungi

Introduction

Haploporus Bondartsev & Singer (Polyporales, Basidiomycota) is characterized by annual to perennial, resupinate to pileate basidiocarps, a di- to trimitic hyphal system with clamped connections on the generative hyphae, cyanophilous skeletal hyphae, cylindrical to subglobose, hyaline, thick-walled, cyanophilous and ornamented basidiospores, and formation of a white rot (Singer 1944, Dai et al. 2002, Piątek 2005, Li et al. 2007, Shen et al. 2016). Pachykytospora was shown to be, micro-morphologically, similar to Haploporus, differing only in having resupinate basidiocarps; both names were treated as synonyms (Dai et al. 2002) and consequently, all Pachykytospora species have been transferred to Haploporus (Dai et al. 2002, Piątek 2005, Shen et al. 2016), but P. major G.Y.Zheng&Z.S.Bi (add lit.), which belong to Megasporia because of its thin-walled and smooth basidiospores (Dai and Li 2002). The monophyly of Pachykytospora was confirmed later on by molecular analysis (Shen et al. 2016). So far 13 species have been accepted in Haploporus (Dai et al. 2002, Hattori et al. 2002, Piątek 2005, Li et al. 2007, Dai and Kashiwadani 2009, Shen et al. 2016).

During a study on taxonomy of Polyporaceae, several specimens of Haploporus from USA, Australia and China were studied. After morphological examinations and phylogenetic analysis of ITS and nLSU sequences, four new species were confirmed to be members of the Haploporus lineage. In this paper, we describe and illustrate these new species. In addition, Poria pirongia G. Cunn. was originally described from New Zealand (Cunningham 1947), and treated as a synonym of Poria papyracea (Schwein.) Cooke (= Haploporus papyraceus (Schwein.) Y.C.Dai&Niemelä (Cunningham 1965, Lowe 1966 and Buchanan and Ryvarden 1988) is shown to represent an independent species, based on new specimens and both morphology and phylogenetic evidences. Therefore, a new combination (H. pirongia) is proposed.

Materials and methods

Morphological studies

Sections were studied microscopically according to Dai (2010) at magnifications ≤1000× using a Nikon Eclipse 80i microscope with phase contrast illumination. Drawings were made with the aid of a drawing tube. Microscopic features, measurements, and drawings were made from sections stained with Cotton Blue and Melzer’s reagent. Spores were measured from sections cut from the tubes. To present spore size variation, the 5% of measurements excluded from each end of the range are given in parentheses. Basidiospore spine lengths were not included in the measurements. Abbreviations include: IKI = Melzer’s reagent, IKI– = negative in Melzer’s reagent, KOH = 5% potassium hydroxide, CB = Cotton Blue, CB+ = cyanophilous, L = mean spore length (arithmetic average of all spores), W = mean spore width (arithmetic average of all spores), Q = the L/W ratio, and n = number of spores measured / from given number of specimens. Color terms follow Petersen (1996). Herbarium abbreviations follow Thiers (2018).

Molecular study and phylogenetic analysis

A CTAB rapid plant genome extraction kit (Aidlab Biotechnologies, Beijing) was used to obtain PCR products from dried specimens, according to the manufacturer’s instructions with some modifications (Cao et al. 2012, Zhao et al. 2013). The DNA was amplified with the primers: ITS5 and ITS4 for ITS (White et al. 1990), and LR0R and LR7 (http://www.biology.duke.edu/fungi/mycolab/primers.htm) for nLSU (Vilgalys and Hester 1990). The PCR procedure for ITS was as follows: initial denaturation at 95 °C for 3 min, followed by 34 cycles at 94 °C for 40 s, 54 °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 34 cycles at 94 °C for 30 s, 50 °C for 1 min and 72 °C for 1.5 min, and a final extension of 72 °C for 10 min. The PCR products were purified and sequenced at the Beijing Genomics Institute, China with the same primers.

Phylogenetic analyses. New sequences, deposited in GenBank (http://www.ncbi.nlm.nih.gov/genbank/) (Table 1), were aligned with additional sequences retrieved from GenBank (Table 1) using BioEdit 7.0.5.3 (Hall 1999) and ClustalX 1.83 (Thompson et al. 1997). The sequence quality were checked followed Nilsson et al. (2012). Perenniporia hainaniana B.K.Cui&C.L.Zhao and P. medulla-panis (Jacq.) Donk were used as outgroups, following Shen et al. (2016). Prior to phylogenetic analysis, ambiguous regions at the start and the end of the alignment were trimmed and gaps were manually adjusted to optimize the alignment were trimmed. The edited alignment was deposited at TreeBase (http://purl.org/phylo/treebase; submission ID 24089).

Table 1.

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Information on the sequences used in this study.

Species	Sample no.	Location	GenBank accession no.
Species	Sample no.	Location	ITS	nLSU
Haploporus alabamae	JV_0610_K16-Kout	Belize	KY264039
	Dollinger 895	USA	KY264038	MK433606
	JV 1704/75	Costa Rica	MK429754	MK433607
*H. angustisporus*	Cui 9046	China	KU941862	KU941887
*H. angustisporus*	Dai 10951	China	KX900634	KX900681
*H. crassus*	Dai 13580	China	FJ627252	KU941886
H. cylindrosporus	Dai 15643	China	KU941853	KU941877
H. cylindrosporus	Dai 15664	China	KU941854	KU941878
*H. gilbertsonii*	JV 1209/63-J	USA	MK429755	MK433608
*H. gilbertsonii*	JV 1611/5-J	USA	MK429756	MK433609
H. latisporus	Dai 11873	China	KU941847	KU941871
H. latisporus	Dai 10562	China	KU941848	KU941872
*H. microsporus*	Dai 12147	China	KU941861	KU941885
H. nanosporus	LYAD 2044a	Gabon	KU941859	KU941883
H. nanosporus	LYAD 2044b	Gabon	KU941860	KU941884
H. nepalensis	Dai 12937	China	KU941855	KU941879
H. nepalensis	Cui 10729	China	KU941856	KU941880
H. odorus	Dai 11296	China	KU941845	KU941869
H. odorus	Yuan 2365	China	KU941846	KU941870
H. cf. odorus	KUC20121123-29	Republic of Korea	KJ668537	KJ668390
H. papyraceus	Dai 10778	China	KU941839	KU941863
	Cui 8706	China	KU941840	KU941864
	KUC20130719-04	Republic of Korea	KJ668535	KJ668388
*H. pirongia*	Dai 18659	Australia	MH631017	MH631021
	Dai 18660	Australia	MH631018	MH631022
	Dai 18661	Australia	MH631019	MH631023
	Dai 18662	Australia	MH631020	MH631024
	PDD 95714	New Zealand	MK429757
H. septatus	Dai 13581	China	KU941843	KU941867
H. septatus	Cui 4100	China	KU941844	KU941868
H. sp.	KUC20080606-35	Republic of Korea	KJ668534	KJ668387
H. subpapyraceus	Dai 9324	China	KU941841	KU941865
H. subpapyraceus	Cui 2651	China	KU941842	KU941866
H. subtrameteus	Dai 4222	China	KU941849	KU941873
	Cui 10656	China	KU941850	KU941874
	Dai11270	China	KY264042
H. cf. subtrameteus	KUC20121102-36	Republic of Korea	KJ668536	KJ668389
H. thindii	Cui 9373	China	KU941851	KU941875
H. thindii	Cui 9682	China	KU941852	KU941876
H. tuberculosus	15559	Sweden	KU941857	KU941881
H. tuberculosus	15560	Austria	KU941858	KU941882
H. tuberculosus (as Pachykytospora)	KA11 (GB)	Sweden	JX124705
	JV 9610/20	Slovakia	KY264040	MK433610
	JV 0509/19	Czech Republic	KY264041	MK433611
Pachykytospora wasseri	LE814872 (T)	Russia	KM411456	KM411472
Perenniporia hainaniana	Cui 6364	China	JQ861743	JQ861759
P. medulla-panis	Cui 3274	China	JN112792	JN112793

Maximum parsimony (MP) and Bayesian inference (BI) were employed to perform phylogenetic analysis of the two aligned datasets. The two phylogenetic analysis algorithms generated nearly identical topologies for each dataset, and, thus only the topology from the MP analysis is presented along with statistical values from the MP and BI algorithms. Most parsimonious phylogenies were inferred from the ITS + nLSU, and their combinability was evaluated with the incongruence length difference (ILD) test (Farris et al. 1994) implemented in PAUP* 4.0b10 (Swofford 2002), under a heuristic search and 1000 homogeneity replicates giving a P value of 1.000, much greater than 0.01, which means there is no discrepancy among the two loci in reconstructing phylogenetic trees. Phylogenetic analysis approaches followed Zhao et al. (2015). The tree construction procedure was performed 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 TBR branch swapping and 1000 random sequence additions. Max-trees 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. jModeltest v.2.17 (Darriba et al. 2012) was used to determine the best-fit evolution model of the combined dataset for Bayesian inference (BI). The Bayesian inference (BI) was conducted with MrBayes 3.2.6 (Ronquist et al. 2012) in two independent runs, each of which had four chains for 10 million generations and started from random trees. Trees were sampled every 1000^th generation. The first 25% of sampled trees were discarded as burn-in, whereas other trees were used to construct a 50 % majority consensus tree and for calculating Bayesian posterior probabilities (BPPs).

Phylogenetic trees were visualized using Treeview (Page 1996). Nodes that received Bootstrap support ≥50% and Bayesian posterior probabilities (BPP) ≥0.90 are considered as significantly supported.

Results

Molecular phylogeny

The combined ITS and 28S dataset included sequences from 46 fungal collections representing 21 species. The dataset had an aligned length of 2054 characters, of which 1399 characters are constant, 98 are variable and parsimony-uninformative, and 557 are parsimony-informative. MP analysis yielded 4 equally parsimonious trees (TL = 1370, CI = 0. 639, RI = 0.870, RC = 0.556, HI = 0.361). The best model for the combined ITS and 28S sequences dataset estimated and applied in the BI was GTR+I+G. BI resulted in a similar topology with an average standard deviation of split frequencies = 0.004515 to MP analysis, and thus only the MP tree is provided. Both BT values (≥50%) and BPPs (≥0.90) are shown at the nodes (Fig. 1). The ITS-based phylogenies included ITS sequences from 47 fungal collections representing 21 species. The dataset had an aligned length of 711 characters, of which 317 characters are constant, 54 are variable and parsimony-uninformative, and 340 are parsimony-informative. MP analysis yielded 4 equally parsimonious trees (TL = 927, CI = 0. 653, RI = 0.888, RC = 0.580, HI = 0.347). The best model for the ITS sequences dataset estimated and applied in the BI was GTR+I+G. BI resulted in a similar topology with an average standard deviation of split frequencies = 0.005040 to MP analysis, and thus only the MP tree is provided. Both BT values (≥50%) and BPPs (≥0.90) are shown at the nodes (Fig. 2).

Figure 1.

Maximum parsimony strict consensus tree illustrating the phylogeny of Haploporus based on ITS+nLSU sequences. Branches are labeled with parsimony bootstrap proportions (before slanting line) greater than 50% and bayesian posterior probabilities (after slanting line) greater than 0.90.

Figure 2.

Maximum parsimony strict consensus tree illustrating the phylogeny of Haploporus based on ITS sequences. Branches are labeled with parsimony bootstrap proportions (before slanting line) greater than 50% and bayesian posterior probabilities (after slanting line) greater than 0.90.

In both 28S+ITS- and ITS-based phylogenies (Figs 1–2), five new well-supported lineages were identified. Among them three well-supported terminal clades and two isolated branches (100% MP and 1.00 BI). Haploporus angustisporus is sister to H. alabamae (Berk. & Cooke) Y.C.Dai&Niemelä and this two species clade is related to H. nanosporus (A.David&Rajchenb.) Piątek, whereas H. gilbertsonii clustered with H. cylindrosporus L.L. Shen, Y.C.Dai&B.K.Cui, H. thindii (Natarajan & Koland.) Y.C.Dai, H. nepalensis (T. Hatt.) Piątek and H. tuberculosus (Fr.) Niemelä&Y.C.Dai. Four Australian specimens and a specimen of Poria pirongia from New Zealand formed a well-supported clade (100% MP and 1.00 BI), sister to the H. odorus clade. In addition, the other two lineages formed two distinct sublineages; Haploporus crassus is closely related to H. papyraceus and H. subpapyraceus L.L.Shen, Y.C.Dai&B.K.Cui; whereas The H. nanosporus and H. microsporus clades are sister clades.

Taxonomy

Haploporus angustisporus Meng Zhou&Y.C.Dai, sp. nov.

MycoBank No: MB829583

Figs 3, 4

Diagnosis

Differs from other Haploporus species by the combination of its resupinate habit, a dimitic hyphal structure with dextrinoid skeletal hyphae, the absence of dendrohyphidia, and distinct narrow oblong basidiospores measuring 10–13.5 × 4–5 µm.

Figure 3.

A basidiocarp of Haploporus angustisporus (Holotype). Scale bar: 1.0 cm.

Figure 4.

Microscopic structures of Haploporus angustisporus (Holotype). a Basidiospores b Basidia c Basidioles d Cystidioles e Hyphae from subiculum f Hyphae from trama.

Holotype

CHINA. Guangdong Prov., Lianzhou County, Nanling Nat. Res., on fallen angiosperm branch, 15 May 2009, Dai 10951 (Holotype in BJFC).

Etymology

Angustisporus (Lat.): referring to the species having narrow basidiospores.

Fruitbody

Basidiocarps annual, resupinate, adnate, soft corky when fresh, become corky upon drying, without odor or tasteless when fresh, up to 3 cm long, 2.5 cm wide, 2 mm thick at center. Pore surface cream to pale yellowish brown when fresh, brownish when bruised, olivaceous buff to pale brown upon drying; sterile margin indistinct, very narrow to almost lacking; pores angular, 3–5 per mm; dissepiments thick, entire. Subiculum cream, corky, thin, about 0.1 mm thick. Tubes light buff, corky, about 1.9 mm long.

Hyphal structure

Hyphal system dimitic: generative hyphae bearing clamp connections, hyaline, thin-walled; skeletal hyphae dominant, thick-walled, frequently branched, dextrinoid, CB+, tissues unchanging in KOH.

Subiculum

Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.5–2.5 µm in diam; skeletal hyphae dominant, hyaline, thick-walled with a narrow lumen to subsolid, frequently branched, interwoven, 1–2.5 µm in diam.

Tubes

Generative hyphae frequent, hyaline, thin-walled, occasionally branched, 1.5–2.5 µm in diam; skeletal hyphae distinctly thick-walled with a narrow to wide lumen, frequently branched, interwoven, 1.2–2.5 µm in diam. Cystidia absent; cystidioles present, fusiform, 23–35 × 4–7 µm. Basidioles dominant, pear-shaped to subglobose, basidia barrel-shaped with 4-sterigmata and a basal clamp connection, 21–26 × 8–11 µm; . Dendrohyphidia absent. Some irregular-shaped crystals present among tube tramal structures.

Spores

Basidiospores oblong, hyaline, thick-walled, with short tuberculate ornamentation, IKI–, CB+, 10–13.5(–14) × (3.5–)4–5 µm, L = 11.25 µm, W = 4.44 µm, Q = 2.38–2.70 (n = 60/2).

Additional specimen examined (paratype)

CHINA. Guangdong Prov., Fengkai County, Heishiding Nat. Res., on fallen angiosperm branch, 1 July 2010, Cui 9046 (in BJFC).

Haploporus crassus Meng Zhou&Y.C.Dai, sp. nov.

MycoBank No: MB829584

Fig. 5

Diagnosis

Diﬀers from other Haploporus species by the combination of a resupinate habit, a dimitic hyphal structure with non-dextrinoid skeletal hyphae, the presence of ventricose cystidioles occasionally with a simple septum, dissepimental hyphae usually with a simple septum, unique thick-walled basidia and distinct wide oblong basidiospores measuring 13.5–16.5 × 7.5–9.5 µm.

Figure 5.

Microscopic structures of Haploporus crassus (Holotype). a Basidiospores b Basidia and Basidioles c Cystidioles d Hyphae from subiculum e Hyphae from trama f Hyphae at dissepiment.

Holotype

CHINA. Yunnan Prov., Xinping County, Ailaoshan Nat. Res., on rotten angiosperm wood, 15 Oct. 2013, Dai 13580 (Holotype in BJFC).

Etymology

Crassus (Lat.): referring to the species having wide basidiospores.

Fruitbody

Basidiocarps annual, resupinate, adnate, soft corky when fresh, become corky and cracked upon drying, without odor or taste when fresh, up to 35 cm long, 3 cm wide and 1 mm thick at center. Pore surface white to cream when fresh, becoming buff-yellow upon drying; sterile margin indistinct, very narrow to almost lacking; pores round, 3–5 per mm; dissepiments thin, mostly entire, sometimes lacerate. Subiculum cream, corky, thin, about 0.1 mm thick. Tubes light buff, corky, about 0.9 mm long.

Hyphal structure

Hyphal system dimitic: generative hyphae bearing clamp connections, hyaline, thin-walled; skeletal hyphae dominant, thick-walled, frequently branched, IKI–, CB+, tissues unchanging in KOH.

Subiculum

Generative hyphae infrequent hyaline, thin-walled, rarely branched, 1.5–2.5 µm in diam; skeletal hyphae dominant, hyaline, thick-walled with a narrow lumen, frequently branched, interwoven, 1–2 µm in diam.

Tubes

Generative hyphae frequent, hyaline, thin-walled, occasionally branched, 1.5–3 µm in diam; skeletal hyphae dominant, distinctly thick-walled with a narrow to wide lumen, frequently branched, interwoven, 1.5–2.5 µm in diam; dissepimental hyphae usually with a simple septum. Cystidia absent; cystidioles present, ventricose, usually with a small umbo having a simple septum, occasionally with a few small guttules, 21–31× 8–10 µm. Basidioles thick-walled, dominant, similar in shape to basidia, but smaller; basidia thick-walled, pear-shaped to barrel-shaped with 4-sterigmata and a basal clamp connection, occasionally with some small guttules, 22–31 × 8–13 µm; dendrohyphidia absent. Some irregular-shaped crystals present among tube tramal stru ctures.

Spores

Basidiospores oblong, hyaline, thick-walled, with tuberculate ornamentation, IKI–, CB+, 13.5–16.5(–17) × (7–)7.5–9.5 µm, L = 15.06 µm, W = 8.15 µm, Q = 1.85 (n = 30/1).

Haploporus gilbertsonii Meng Zhou, Vlasák&Y.C.Dai, sp. nov.

MycoBank No: MB829649

Figs 6, 7

Diagnosis

Diﬀers from other Haploporus species by its relatively large pores, 2–3 per mm, a dimitic hyphal structure with non-dextrinoid skeletal hyphae, the absence of dendrohyphidia, and wide oblong basidiospores measuring 12–15 × 6–8 µm.

Figure 6.

A basidiocarp of Haploporus gilbertsonii (Holotype). Scale bar: 1.0 cm.

Figure 7.

Microscopic structures of Haploporus gilbertsonii (Holotype). a Basidiospores b Basidia c Basidioles d Cystidioles e Hyphae from subiculum f Hyphae from trama.

Holotype

USA. Arizona, Santa Rita Mt., Madera Canyon, on dead tree of Quercus, 20 Nov. 2016, Vlasák Jr. 1611/5-J (Holotype in PRM, isotype in JV and BJFC).

Etymology

Gilbertsonii (Lat.): in honor of Prof. R.L. Gilbertson, the American mycologist.

Fruitbody

Basidiocarps annual, resupinate, difficult to separate from the substrate, corky when dry, up to 10 cm long, 8 cm wide and 0.8 mm thick at center. Pore surface pale buff to buff when dry; sterile margin indistinct, very narrow to almost lacking; pores round to angular, 2–3 per mm; dissepiments thick, entire. Subiculum cream, corky, thin, about 0.3 mm thick. Tubes light buff, corky, about 0.5 mm long.

Hyphal structure

Hyphal system dimitic: generative hyphae bearing clamp connections, hyaline, thin-walled; skeletal hyphae dominant, thick-walled, frequently branched, IKI–, CB–, tissues unchanging in KOH.

Subiculum

Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, 2–3 µm in diam; skeletal hyphae dominant, hyaline, distinctly thick-walled, frequently branched, interwoven, 1.5–3 µm in diam.

Tubes

Generative hyphae infrequent, hyaline, thin-walled, occasionally branched, 1–3 µm in diam; skeletal hyphae dominant, distinctly thick-walled, frequently branched, interwoven, 2–4 µm in diam. Cystidia absent; cystidioles present, fusiform, hyaline, thin-walled, 13–23 × 4.5–6 µm. Basidia pear-shaped to barrel-shaped with 4-sterigmata and a basal clamp connection, occasionally with a few large guttules, 21–25 × 10–14 µm; basidioles dominant, similar in shape to basidia, but slightly smaller. Dendrohyphidia absent. Some irregular-shaped crystals present among tube tramal structures.

Spores

Basidiospores oblong, hyaline, thick-walled, with tuberculate ornamentation, IKI–, CB+, 12–15(–16) × (5.5–)6–8 µm, L = 14.07 µm, W = 6.9 µm, Q = 1.83–2.15 (n = 60/2).

Additional specimen examined (paratype)

USA. Arizona, Chiricahua Mt., Turkey Canyon, on dead tree of Quercus, 5 Sep. 2012, Vlasák Jr. 1209/63-J (JV, dupl. in BJFC).

Haploporus microsporus Meng Zhou&Y.C.Dai, sp. nov.

MycoBank No: MB829585

Figs 8, 9

Diagnosis

Diﬀers from other Haploporus species by the combination of a resupinate habit, a dimitic hyphal structure with dextrinoid skeletal hyphae, distinct small pores, 7–9 per mm, the presence of dendrohyphidia, and distinct small ellipsoid basidiospores measuring 5.3–6.7 × 3–4.1 µm.

Figure 8.

A basidiocarp of Haploporus microsporus (Holotype). Scale bar: 1.0 cm.

Figure 9.

Microscopic structures of Haploporus microsporus (Holotype). a Basidiospores b Basidia and Basidioles c Cystidioles d Dendrohyphidia e Hyphae from subiculum f Hyphae from trama.

Holotype

CHINA. Hainan Prov., Ledong County, Jianfengling Nat. Res., on dead angiosperm tree, 23 March 2011, Dai 12147 (Holotype in BJFC).

Etymology

Microsporus (Lat.): referring to the small basidiospores of this species.

Fruitbody

Basidiocarps annual, resupinate, adnate, soft corky when fresh, become corky upon drying, odor- or tasteless when fresh, up to 20 cm long, 4.5 cm wide and 2 mm thick at center. Pore surface pinkish buff to clay-buff when dry; sterile margin indistinct, very narrow to almost lacking; pores angular, 7–9 per mm; dissepiments thick, entire. Subiculum cream, corky, thin, about 0.2 mm thick. Tubes light buff, corky, about 1.8 mm long.

Hyphal structure

Hyphal system dimitic: generative hyphae bearing clamp connections, hyaline, thin-walled; skeletal hyphae dominant, thick-walled, frequently branched, dextrinoid, CB–, skeletal hyphae swollen in KOH.

Subiculum

Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.5–2.5 µm in diam; skeletal hyphae dominant, hyaline, thick-walled with a narrow to wide lumen, frequently branched, interwoven, 1.5–3 µm in diam.

Tubes

Generative hyphae infrequent, hyaline, thin-walled, rarely branched, 1.5–3 µm in diam; skeletal hyphae distinctly thick-walled with a narrow lumen to subsolid, frequently branched, interwoven, 1–2 µm in diam. Cystidioles present, fusiform, 10–20 × 3.5–6 µm. Basidia barrel-shaped with 4-sterigmata and a basal clamp connection, 11–16 × 5.5–6.5 µm; basidioles dominant, similar in shape to basidia, but slightly smaller. Dendrohyphidia abundant, frequently branched. Some irregular-shaped crystals present among tube tramal structures

Spores

Basidiospores ellipsoid, hyaline, thick-walled, with tuberculate ornamentation, dextrinoid, CB+, 5.3–6.7(–7) × (2.9–)3–4.1 µm, L = 5.98 µm, W = 3.90 µm, Q = 1.78 (n = 30/1).

Haploporus pirongia (G. Cunn.) Meng Zhou, Y.C.Dai&T.W. May, comb. nov.

MycoBank No: MB829650

Figs 10, 11

Poria pirongia G. Cunn., Bull. N.Z. Dept. Sci. Industr. Res., Pl. Dis. Div. 72: 39 (1947) (Basionym)

Etymology

the epithet pirongia, derived from the type locality, Mount Pirongia, is a noun in apposition, and therefore remains spelt the same when transferred from Poria to Haploporus, despite the latter genus being masculine in gender.

Fruitbody

Basidiocarps annual, resupinate, difficult to separate from the substrate, soft corky when fresh, corky upon drying, odor- or tasteless when fresh, up to 8 cm long, 2 cm wide and 1.7 mm thick at center. Pore surface white to cream when fresh, pale brownish when bruised, pinkish buff to clay-buff upon drying; sterile margin very narrow to almost lacking; pores round to angular, 3–4 per mm; dissepiments thick, entire. Subiculum cream, corky, thin, about 0.3 mm thick. Tubes light buff, corky, about 1.4 mm long.

Hyphal structure

Hyphal system trimitic: generative hyphae bearing clamp connections, hyaline, thin-walled, frequently branched; skeletal hyphae dominant, thick-walled to subsolid, hyaline to slightly yellowish, frequently branched; binding hyphae abundant, slightly thick-walled, IKI–, CB+, tissues unchanging in KOH.

Subiculum

Generative hyphae frequent, hyaline, thin-walled, frequently branched, 2.3–3.5 µm in diam; skeletal hyphae dominant, hyaline, distinctly thick-walled with a narrow lumen to subsolid, occasionally branched, interwoven, 2.5–4 µm in diam; binding hyphae abundant, slightly thick-walled,1–2 µm in diam.

Tubes

Generative hyphae frequent, hyaline, thin-walled, frequently branched, 1.7–3.5 µm in diam; skeletal hyphae distinctly thick-walled with a narrow to wide lumen, frequently branched, interwoven, 2.5–4 µm in diam; binding hyphae slightly thick-walled,1–2.5 µm in diam. Cystidia absent; cystidioles present, fusiform, occasionally with an apical simple septum, sometimes with a few small guttules, 21–28 × 5–7 µm. Basidioles dominant, similar in shape to basidia, but slightly smaller, occasionally with a few large guttules; basidia pear-shaped to barrel-shaped with 4-sterigmata and a basal clamp connection, 21–35 × 8–11 µm. Hyphae at dissepiment usually thick-walled with simple septum. Dendrohyphidia absent. Some irregular-shaped crystals present among tube tramal structures.

Spores

Basidiospores oblong-ellipsoid to cylindrical, hyaline, thick-walled, with tuberculate ornamentations, some with a guttule, IKI–, CB+, 11–14(–15) × (4.8–)5.2–7 µm, L = 12.35 µm, W = 6.11 µm, Q = 1.83–2.15 (n = 90/3).

Specimens examined

AUSTRALIA. Victoria, Melbourne, Dandenong Ranges Botanical Garden, on dead branch of Rhododendron, 12 May 2018, Dai 18659, 18660 & 18661 (MEL, dupl. in BJFC); on dead branch of Eucalyptus, 12 May 2018, Dai 18662 (MEL, dupl. in BJFC). NEW ZEALAND. Omahu Bush, on Melicytus, 15 Feb 2010, Cooper (PDD 95714, dupl. in BJFC).

Figure 10.

Basidiocarps of Haploporus pirongia. Scale bar: 1.0 cm.

Figure 11.

Microscopic structures of Haploporus pirongia. a Basidiospores b Basidia c Basidioles d Cystidioles e Hyphae from subiculum f Hyphae from trama g Hyphae at dissepiment.

Haploporus odorus (Sommerf.) Bondartsev & Singer in Singer, Mycologia 36: 68 (1944)

=Haploporus amarus X.L. Zeng & Y.P. Bai, Acta Mycol. Sin. 12(1): 13 (1993). Holotype: China, Jilin Province, Northeast Normal University, Changchun, NENU, Zeng 1931.

Notes

Haploporus amarus was described from NE China (Zeng and Bai 1993). The type was studied, and its morphology is in agreement with that of H. odorus.

Haploporus subtrameteus (Pilát) Y.C.Dai&Niemelä, in Dai, Niemelä and Kinnunen, Ann. bot. fenn. 39(3): 181 (2002)

=Pachykytospora wasseri Zmitr., Malysheva & Spirin, Ukrainskiy Botanichnyi Zhurnal 64(1): 42 (2007) Holotypus: Russia, Samara Reg., Stavropol Dist., Zhiguli Nat. Res., Padus avium, 12.09.2006, V.F. Malysheva, E.F. Malysheva, I.V. Zmitrovich, isotypus, LE 214872.

Notes

In our phylogenies (Figs 1 and 2), P. wasseri (Zmitrovich et al. 2007) nested within H. subtrameteus clade. In addition, there are not major morphological differences between the two taxa (Zmitrovich et al. 2007).

Discussion

In the ITS-based phylogeny (Fig. 2), Haploporus angustisporus is closely related to H. alabamae and H. nanosporus. Morphologically, Haploporus angustisporus may be confused with H. alabamae in having approximately the same basidiospores size (9.5–12.5 × 4–5.5 µm vs. 10–13.5 × 4–5 µm) but H. alabamae has a trimitic hyphal system and lacks cystidioles (Gilbertson and Ryvarden 1986–1987). Haploporus nanosporus differs from H. angustisporus by its smaller pores (9–12 per mm vs. 3–5 per mm), non-dextrinoid skeletal hyphae, and smaller basidiospores (5–6 × 3–4 µm vs. 10–13.5 × 4–5 µm, Piątek 2005).

Haploporus gilbertsonii is closely related to H. cylindrosporus, H. thindii, H. nepalensis and H. tuberculosus. However, Haploporus thindii differs from H. gilbertsonii by its distinctly slimmer basidia (20–37 × 6.5–9.1 µm vs. 21–25 × 10–14 µm) and the absence of cystidioles (Yu et al. 2005). Haploporus nepalensis is distinguished by its smaller basidiospores (5.5–11.5 × 4.5–6.5 µm vs. 12–15 × 6–8 µm) and the absence of cystidioles (Piątek 2003). Whereas Haploporus tuberculosus is distinguished from H. gilbertsonii by its trimitic hyphal system and longer basidia (30–43 × 11–13.5 µm vs. 21–25 × 10–14 µm, Ryvarden and Gilbertson 1994).

The Haploporus nanosporus and H. microsporus clades are sister clades and Haploporus nanosporus is closely related to H. alabamae and H. angustisporus. Haploporus and H. nanosporus both have small basidiospores and occurs in tropical ecosystems,and all other differing in having larger basidiospores. However, H. nanosporus differs from H. microsporus by the absence of dendrohyphidia at the dissepiments, a trimitic hyphal system and absence of cystidioles (Piątek 2005). In addition, Haploporus alabamae differs from H. microsporus through a trimitic hyphal system and absence of cystidioles (Gilbertson and Ryvarden 1986–1987). Haploporus angustisporus differs from H. microsporus by its longer basidiospores (10–13.5 × 4–5 µm vs. 5.3–6.7 × 3–4.1 µm).

In the ITS-LSU based phylogeny (Fig. 1), Haploporus crassus is closely related to H. papyraceus and H. subpapyraceus. However, morphologically Haploporus papyraceus differs from H. crassus by the presence of dendrohyphidia at the dissepiments, absence of cystidioles and thin-walled basidioles (Ryvarden and Johansen 1980). Haploporus subpapyraceus also differs from H. crassus in having dextrinoid skeletal hyphae and thin-walled basidioles (Shen et al. 2016).

Haploporus pirongia is related to H. odorus, but the latter has a perennial and pileate basidiocarp with strong anise odor, ovoid basidiospores and lacks cystidioles (Niemelä 1971). Haploporus pirongia resembles H. thindii and H. subpapyraceus by sharing resupinate basidiocarps with approximately the same pore size. However, Haploporus thindii has a dimitic hyphal structure, lacks cystidioles, and has a distribution in subtropical India and valley of Tibet of China (Natarajan and Kolandavelu 1993, Dai et al. 2007). Moreover, H. subpapyraceus has ellipsoid basidiospores (9–12 × 5.5–8 μm, Shen et al. 2016).

Gilbertson and Ryvarden (1987) reported Haploporus tuberculosus (as Pachykytospora tuberculosa) from the USA, but only in a small region of southern Arizona where it should be “quite common on oaks, especially in Chiricahua Mountains”. Locally, we have collected in this region only H. gilbertsonii and believe that, in most cases, this species was mistaken for H. tuberculosus in Arizona. The presence of H. tuberculosus in America is questionable.

Acknowledgements

The research is supported by the National Natural Science Foundation of China (Project No. U1802231). We thank the curator of PDD for making material available on loan, and Shaun Pennycook for advice on the spelling of epithets.

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