)0 s. Mr. 1. Bot. 1998, 64( 1130- 37 Stereum species (Stereaceae) of South Africa Albert Eicker* and Sandra Louw Department of Botany, University of Pretoria, Pretoria 0002 Republic of South Africa Received 3 June 1997; revised 20 August J 997 Seven species of Stereum HiIl:Pers. are recognised for South Africa. Three species, S. hirsutum, (Willd,:Fr.) Gray, S. rimosum Berk. and S. ochraceo-flavum (Schwein.) Ellis, have only ordinary hyphidia and belong to the subgenus Stereum. S. rimosum var africanum P.H.B. Talbot is reduced to synonymy with S. rimosum. S. vel/ereum Berkeley is reduced to synonymy with S. ochraceo-flavum. S. lobatum (Kunze:Fr.) Fr., S. australe Lloyd and S. sanguino/entum (Alb. & Schwein .:Fr.) Fr. , possess pseudoacanthohyphidia and therefore belong to the subgenus Aculeatostereum. Representatives of the S. ostrea complex in South Africa are S. lobatum and S. austra/e, both considered well ~ defined species. S. durbanense van der Sijl is considered a synonym of S. australe. S. illudens Berk. is the only species recognised in th is study as possessing acanthohyphidia and therefore belongs to the subgenus Acanthastereum. A dichotomous key based on micro- and macromorphological characters is given for the seven South African species. Keywords: Stereum, S. austra/e, S. hirsutum, S. illudens, S. fobatum, S. ochraceo-flavum. S. rimosum, S. sanguinolentum, South African fungi. *To whom correspondence shou ld be add ressed. Introduction be of great importance in the taxonomy of this genus. had either Talbot's (1954) concept of the genus Siereum in South Africa not been described or their importance had not been appreciated was analogous with that of Burt (1920) and included 'stereoid' when Talbot (1954) wrote his paper on South African stereums. fungi in a very broad sense. Lignicolous and terrestrial, stipitate It became clear that there was an urgent need for a modern taxo­ and non-stipitate forms were included, as well as species that nomic revision of South A frican representatives of this genus. possessed cystidia, gloeocystidia and vesicles; many species now known to be unrelated were included in the genus. Materials and Methods John Hill in 1751 was the first person to use the name Stereum South African specimens coll~cted during this study. as well as ~:\ist­ in a generic sense (Chamuris 1988). Between 1955 and 1968 the ing herbarium specimens housed in PREM (herbarium of th e generic limits of Stereum were more precisely defined as a result National Collection of Fungi, Pretoria) Of in PRU(M) (fungus collec­ ofa shifting emphasis towards the use of microscopic characters tions of the H.G.W.J Schweickerdt Herbarium. University of Preto~ (Chamuris 1988 1. Lentz (19551, Boidin (19581, Pouzar (19591 ria) were studied. and Parmasto ( 1968) played a major part in this circumscription In the present study \ve fo !lm\-' Hawksworth et al. (1 995} in descrihing the basidiOinata and Cham uris (1988) for the micromor­ by including only those species which were obviously closely phology. Externnl colours of the bas idioillata are based on Rayner's related to the type species, S. hirsutum. The genera Laxitextum, (19701 co loor chart. Cryplochaele, Amy/oslereum, Boreoslereul11. Chondroslerellm. Cystosteteum, Lallrifia, Dendrocorticium, Dendrophora. Descriptions Lopharia, Peniophora and Phanel'ochaete were either erected or utilised to accommodate the many species segregated from the SteTeurn Hill:Pers., Neues Mag. Bot. I: 11 0. 1794. genus Slereum sensll 1010. These include all the stipitate forms Basidiomata effuso-rdlexed to sessile. rarely completely resupinate. (Reid 1965) as well as those effuso-reflexed, dirnidiate or resupi­ often orbicular nnd umbonate. conflucnt. gregarious. usually curia~ nate forms that posses cystidia (encrusted, gloeocystidia or sulfo­ ceo us. sometimes corky Of papery. tough to hard. annual or peren~ cystidia) or vesicles as well as the species in which the nial. Abhyrnenial surface at first tomentose. strigose~hirsute to basidiomata posses clamps (on hyphae or as a basal clamp of a hispid or velutinate. usually bccoming glabrous in zones. often basidium). exposing a·dark coloured cutis. furrowed to sulcate. white to ochre~ Thus, by 1968 Slerewn represented a homogenous group of ous to rusty brown. usually colour zoned. Hymenial surface usually species that could be interpreted as comprising a natural or smooth (even), sometimes rimose or slig.ht ly tlIberculate. often con ~ monophyletic group (Cham uris 1988). Today the genus Sterellm centrically ridged. creamy yellow. greyish yc ll O\ ..... to orange to is restricted to species having smooth, amyloid, binucleate brown. sometimes rosy tinted. some species bruising red, orange yc l~ low or yellow when inj ured, thickening hymenium, homogenous or spores, dimitic basidiomata without clamps and with pseudocys~ stratose. tidia. It is also characterised by holocoenocytic nuclear behav~ Hypha' system: dimitic: generative hyphae with simple septa. iour and sparse, opposite or verticillate clamps on the broader moderately branched, th in to thick~wa ll ed : skeletal hyphae inrre ~ hyphae of monos porous as well as polysporous cultures (Boidin quently septate or aseptate, slightly thick~walled to thick~walled. et af. 1979). The closely related genus Xylobolus is maintained as curving into the hymeniul1l and ending as pseudocystidia. a distinct genus in the same evoh,ltionary line as (Cha~ Stel'eum Pseudocystidia: apically thin-walled. often filted with oily to g r anLl~ muris 19881. The genus is now well defined (Chamuris 1988; lar substance or crystals. contents hyaline to brown: not encrusted. Hjortstam & Ryvarden 19891. Hyphidia: acute or cylindrical. ordinary hyphidia. as well as ac an~ in South Africa these fungi have been neglected by collectors thohyphidia or pseudoacanthohyphidia. Basidia: clavate to subcy lin~ in the past, compared with the larger pileate forms. The last study drical, with four sterigmata. basal t:lnl1lp absent. Basidiospores: of the genus Stereum in this country was that of Talbot (1954). ellipsoid to cylindrical. binucleah:. hyaline. sm ooth, th i !1 ~ walled. Many of the different hymenial elements currently considered to amyloid. S. Afr. J. Bot. 1998.64( 1) 31 matted-tomentosc. oftt!Jl r.:o llccllirically furrowed: COllcl.! lltrieali v col­ our-zollt!d: tomentum hutf to ocbre, ~lsually greyish in older ~pans, exposed cutis light orange to hazc::l in thin concentric lanes. Hyme~ nial surface evt!ll. wi th or without concentric ridges; specimens wuh large resupinate area often rimost: arollnd central wart. sometim es cnicking radially 011 drying: satlron when dry ,,, jlh vinaceous tn1ft' or hazel tinges where injured or bruised, never hruiscs rcd. light yc::llow to orange when fresh. margin oftcn thin. Thickness in section: 390-810 pm. ('utIS: brown to light yd­ low-brown. Skeletalltyphae: (3.0-)~J..O-9 .() ( - II.O) ~ lI n dianL wall thickness 1.0-4.0 ~1l11. (rene/'afivl! hyphae: 2.0- 30(--4.0) pm diam. Tomental hair: 5.0-(1.0( - 9.0) /-I1ll. small lumen, walls 2.1l-3.0 j.llll thick. Basidia: narrowly cia vall! to suhcylindrical. 4~ s l l!rigmate. basal clamp absent. 21 - 35 x 4.0- S.U ~llll. Basidiospores: 5.U- 7.S( - 8.0) x 2.0--3.0(-3.5) j.lm. ellipsoid to cylindri cal. binuclt!ate. hyaline. smooth, thin-walled. amyloid. HyphiJi{/: mostly acuminate. occa ~ sionally cylindrical. thin-walled, 2.0- 3.0 ~Ull diam. Pseudocys[ulia: cy li nd rical to subcylindrical. thick-walb.l at basl!, thill-walled epi­ cally. hyaline to yellow, oily contents, 5.0-- 11 ~lIn diam. Figure 1 5;tereum hirmtull1. A. Vertical section of basidioma. B. Specimens examinl!d: PREM : 47648. 4 7646. 4~651. 2131 (as S vel­ Tomental hilir. C. Portion of hymenium showing pseudocystidia lerellnl Berk. ), 156 10 I (as S ~,(,/len:' llm). PRU(M): 25 13. 2588. (p), ordinary hyphidia (h) basidia (b) and basidiospores. 2632. 25 05. 1163. 2708. 2562. 3190. ]205. 3209. 3198. ]685. 3194. Type species: Thelephora !drs/{lG Wi ll d.:Fr. 3195.3 197.3 191. 3192. 3 193. 3207. 3206. 3204. 32(11. 3200. 3202. 3208.3196.3 187.3203. 32 10. Although some recent authors consider Stereuf11 to be monoJU­ itic, it is regarded as dimitic in this paper. The reason is that two None of the freshly collected specimens clearly bled or bruised, types of hyphae are present: thin-wall ed simple-septate hyphae, but some very moist ones occasionally exuded clear yell ow drop­ the generative hyphae and thicker walled, aseptate or sparsely lets or bruised yellowish to ] ight brownish, drying a brown. grey septate, very long, un branched hyphae which morphologically or purple colour. Pseudocystidia never showed brown or red con­ meet the definition of skeletal hyphae. The skeletal hyphae differ tents. Fresh basidiomata placed in water with the hymeniu!l1 to some extent in the different Stel'elfm species, ranging from upwards, turned the water yell ow and often formed a clear yel­ slight ly th ic k- to thi ck-walled and infrequently septate. The ends low exudate on the hymeni al surface.. \: hir:mlum is readily dis­ of some skeletal hyphae curve into the hymenium and are modi­ tinguishable by th e yellow to orange hyrn eniulll, the hirsllte fied as pseudocystidia, w hile some penetrate into the hymenium tomentum and the presence of a brown cutis. without modification. It seems that skeletal hyphae are much Slereum ochraceo-j1al'lIlJl (Schwein.) Ellis. North American more abundant in the firmer, retlexed and sessile species than the Fungi, no. 17 . 1878. (Fi gures :2 and J). thinner, resupinate ones, which may be indicative of their func­ tion. T he skeletal hyphae may have a brown to hyaline colour Basionym: Thelephora uc:hranm-/lol'lI Schwein.. Trans. and usually run radially through the context, except where their Amer. Philos. Sm. (n .s.) 4: 167.