Two new Phallus species, P. cremeo-ochraceus and P. rigidiindusiatus were discovered in southwestern and southern China, respectively. Phallus cremeo-ochraceus is morphologically characterized by its cream to ochraceous receptacle, white to very slightly pinkish indusium, white to pinkish pseudostipe and white to slightly purplish pink volva. Phallus rigidiindusiatus is characterized by a white to yellowish white receptacle, a strongly rigid indusium usually without serrated margin and smaller basidiospores than those of P. serratus. Phylogenetic positions of the two species are located in two independent lineages respectively. Detailed descriptions, color photographs, illustrations and a key to the related species are presented.

Edible mushrooms, Gasteromycetes, Phallus indusiatus, phylogeny, taxonomy

Phallus Junius ex L. (1798) is a well-known and widespread gasteroid genus from tropical to temperate zones. Studies based on molecular phylogenetic analyses about a dozen years ago have shown that the existence of an indusium and a perforate pore at top of receptacle has no phylogenetic significance at generic level, and members of Dictyophora Desv. (1809), which are mainly characterized by possession of an indusium, should be merged into genus Phallus (Cabral et al. 2012; Moreno et al. 2013). In the last decade, quite a lot of species with or without an indusium have been discovered under the genus of Phallus (Mohanan 2011; Li et al. 2014; Rebriev et al. 2014; Adamčík et al. 2015; Li et al. 2016; Medeiros et al. 2017; Trierveiler-Pereira et al. 2017; Song et al. 2018; Cabral et al. 2019; Li et al. 2020a).

Thirty-one species, nearly one-third of the world’s total members of known Phallus species, have been recorded in China, and sixteen of them were originally reported from there. Many of them are notably edible mushrooms, for instance, Phallus fragrans M. Zang, P. haitangensis H.L. Li, P.E. Mortimer, J.C. Xu & K.D. Hyde, P. lutescens T.H. Li, T. Li & W.Q. Deng and P. luteus (Liou & L. Hwang) T. Kasuya; and some have even been produced commercially, e. g. P. dongsun T.H. Li, T. Li, Chun Y. Deng, W.Q. Deng & Zhu L. Yang, P. echinovolvatus (M. Zang, D.R. Zheng & Z.X. Hu) Kreisel, P. rubrovolvatus (M. Zang, D.G. Ji & X.X. Liu) Kreisel and P. serratus H. Li Li, L. Ye, P.E. Mortimer, J.C. Xu & K.D. Hyde (Zang end Ji 1985, 1988; Kreisel 1996; Kasuya 2008; Li et al. 2014, 2016, 2020a).

In the past decades, Phallus indusiatus Vent. (1798), characterized by a white and touching-ground indusium, had been reported from the tropical and subtropical Africa and Asia, temperate China, Japan, South Pacific islands, Australia and South America (Dring 1964; Kobayasi 1965; Liu et al. 2005; Young 2005; Cabral et al. 2019). However, recent studies revealed that many collections named as “ Phallus indusiatus” or “Dictyophora indusiata (Vent.) Desv. (1809)” were misidentified, and P. indusiatus might be only distributed in Brazil and adjacent countries in South America, rather than widespread from the temperate and subtropical zones (Zang and Ji 1985; Calonge et al. 2005; Song et al. 2018; Cabral et al. 2019). Phallus indusiatus s.s. has recently been redescribed with a neotype, which strongly suggested that the P. indusiatus-like species from other continents should be considered different taxa from P. indusiatus s.s. (Cabral et al. 2019).

During these years, the authors further investigated the diversity of Phallus species from China with some new collections. Based on detailed morphological data and DNA-based phylogenetic analyses, two additional new P. indusiatus-like species to science were confirmed, and then formally introduced in this study.

Based on the ITS dataset P. cremeo-ochraceus nested in a group containing P. luteus, P. echinovolvatus, P. fuscoechinovolvatus and P. multicolor (Figure 1). However, in the ITS-LSU dataset P. cremeo-ochraceus separates from them and formed an independent clade (Figure 2). Therefore, the sister relationships of P. cremeo-ochraceus remain unclear. Morphologically, all of them have similar color in receptacle except P. multicolor and P. luteus which have a bright yellow to orange indusium (Berkeley and Broome 1883; Kasuya 2008).

Phylogenetically, P. rigidiindusiatus is closely related to P. serratus and P. haitangensis with strong support (Figures 1, 2). Morphologically, P. serratus resembles P. rigidiindusiatus in having a white and strongly reticulate receptacle, a white and well-developed indusium and a brownish-gray volva. However, P. serratus can be easily distinguished from the new species in having the serrated meshes of indusium and larger basidiospores (4–5 × 2–3 µm) (Li et al. 2014); Phallus haitangensis is another closely related taxon, which is different in its golden orange receptacle and a well-developed, light orange indusium (Li et al. 2016). Interestingly, P. haitangensis and P. serratus have distinct morphological characteristics but shared with a 98.4% similarity of ITS sequence (Li et al. 2014, 2016). Both two new species were separated from P. indusiatus in phylogenetical analyses.

Other Phallus species with a white indusium are relatively easier to be distinguished from the new species P. cremeo-ochraceus and P. rigidiindusiatus (Table 2). For example, the Chinese species P. echinovolvatus and P. fuscoechinovolvatus are distinguished by having an obviously echinate volva (Zang et al. 1988; Song et al. 2018); and P. atrovolvatus Kreisel & Calonge, described from the Central America, can be easily distinguished by having a rugulose to merulioid receptacle, a black volva, and an indusium expanded to midway from the receptacle and volva (Calonge 2005). Although the Brazilian species P. aureolatus L. Trierveiler-Pereira & A.A.R. de Meijer has a rigid, white and almost touching ground indusium which is similar to that of P. rigidiindusiatus, it differs in having a rugulose to merulioid receptacle, a shorter pseudostipe (up to 10 cm high) and a shorter basidiospores (3.0–4.1 × 1.5–2.0 μm) (Trierveiler-Pereira et al. 2017).

Among the complex members of P. indusiatus s.l. published by Cabral et al. (2019), P. denigricans T.S. Cabral, B.D.B. Silva & Baseia has a volva varying from white to dark brown and basidiospores up to 4.6 × 2.5 µm; Phallus purpurascens T.S. Cabral, B.D.B. Silva & Baseia has a white receptacle, a purplish volva and larger basidiospores (4.4–5 × 2.5–3.4 µm); and P. squamulosus T.S. Cabral, B.D.B. Silva & Baseia is characterized by its squamous surfaces of immature basidioma and volva. Besides, P. maderensis Calonge, described from the Atlantic Island of Africa, has an interesting indusium attaching to the base of pseudostipe and is not hanging from the receptacle (Calonge et al. 2008); and P. merulinus (Berk.) Cooke from Indonesia differs in a rugose receptacle with minutely convoluted folds (Lloyd 1909). The Chinese species P. rubrovolvatus is distinguished by the red purple volva, although it also has a rigid indusium reaching on the midway or 3/4 portion of the pseudostipe (Liu et al. 2005); and P. ultraduplicatus X.D. Yu, W. Lv, S.X. Lv, Xu H. Chen & Qin Wang from northeastern China has a shorter indusium hanging down less than 1/2 portion of the pseudostipe and longer and narrower basidiospores than those of P. rigidiindusiatus (Adamčík et al. 2015).

According to the original description, Phallus indusiatus, a South American species, is characterized by the campanulate and reticulated receptacle and the white indusium touching the ground (Ventenat 1798). However, it was not possible to find the original material in herbarium for comparison due to the unspecific information (Ventenat 1798). Recently, based on same characteristics as the original description, close geographical location with the same forest domain, and submitted the available molecular sequences to GenBank, a neotype of P. indusiatus was designated, which has a campanulate and reticulated receptacle, a white and fully developed indusium, a white volva and elongated and smooth basidiospores (3.6–4.1 × 1.5–2.2 µm); according to all known data about the Phallus taxa, its distribution is presumed to be restricted to South America (Cabral et al. 2019).

In phalloid fungi, macro-characters, such as the shape, the surface characters and color of the main structures (receptacle, pseudostipe, indusium, volva and rhizomorphs), are generally more important than micro-characters for infrageneric classification (Kreisel 1996). Therefore, if without any molecular phylogenetic analyses, two or more species shared similar macro-characters, then these could easily be confused for the same species. However, when geographical distribution has been taken into account as the taxonomic evidence, they tend to become easily distinguishable, because phalloid fungi have a passive basidiospore dispersal mechanism that depends mainly on insects as transporters, and this factor together with environmental conditions (such as temperature, humidity, illumination, soil nutrition and dominated plants) arguably limit their geographical distributions (Wilson et al. 2011). According to our previous studies, for example, quite a lot of Asian specimens labeled as “P. impudicus” were actually identical to P. dongsun from China, and Phallus rubicundus (Bosc) Fr. originally described from America was probably not naturally distributed in China, even in Asia (Li et al. 2020a, b). Therefore, morphological analyses and geographical distributions, as well as molecular phylogeny are the most useful evidences to identify the phalloid fungi. The two Phallus indusiatus-like species from China were proven as new to science with strong supports of those evidences in this study while the natural distribution of P. indusiatus in China becomes more suspicious.

The authors express sincere gratitude to Dr. Chunying Deng, Mr. Guorui Zhong and Mr. Hao Huang for collecting the specimens, also to Dr. Chaoqun Wang and Dr. Md. Iqbal Hosen for their helpful suggestions on improving the morphological descriptions, molecular phylogenetic analyses, figure illustration and references. This work was funded by the National Natural Science Foundation of China (31800014, 31970016); the Science and Technology Planning Project of Guangdong Province, China (2019B121202005, 2018B020205001, 2018B030324001); the Science and Technology Planning Project of Guizhou Province, China [No. Qian Ke He Fu Qi (2019) 4007]; the project of macrofungi investigation in Shenzhen (SZCG2019191412) and the project of Macrofungal Investigation in Zhongshan (ZZ21901438). We also sincerely thank the two anonymous reviewers for their corrections and suggestions to improve the paper.