PERSOONIA Published by theRijksherbarium, Leiden Part Volume 7, 4, pp. 443-581 (1974) Studies in the genera Irpex and Steccherinum R.A. Maas+Geesteranus Rijksherbarium, Leiden and Plate (With 34 Text-figures 40) In the is while present paper Irpex maintained as a monotypic genus, Of these S. Steccherinum is accepted with 17 species. ethiopicum, S. galeritum, S. gilvum, S. lanestre, and S. willisii are described as new species, S. hydneum is proposed as a new combination. A considerable of the is devoted all the proportion paper to species (and a that have described in transferred few subspecific taxa) been wrongly or to Irpex and Steccherinum. Some of the specific epithets are transferred to other such Beenakia Climacodon genera, as (p. 555), (p. 546), Dentipellis (p. 551, 558) and Hyphodontia (p. 567). Contents Introduction 444 General part 445 Macroscopic characters 445 Chemical data 446 Hyphal construction 446 Clamp-connections 448 Basidia 448 Spores 448 Genetic characters 448 Cultural characters 448 Affinities 449 of Hyphenation specific epithets 450 Taxonomic part 450 Fr la. Irpex 450 ib. Irpex lacteus (Fr. ex Fr.) Fr 451 of the ic. Types synonyms: descriptions and comments 453 id. Excluded or insufficiently known taxa 457 Steccherinum S. F. 2a. Gray 503 the 2b. Key to species; specific descriptions 504 and 2c. Types of the synonyms: descriptions comments 529 2d. Excluded or insufficiently known taxa 544 References 570 Index 575 443 1 PERSOONIA Vol. Part 444 7, 4, 1974 Introduction the the and Steccherinum have been but In past genera Irpex given scant attention that both served convenient for that wanted except as repositories species were not or seemed out of place elsewhere. With the generic boundaries so little fixed it is not surprising that in the course of time both attracted a considerable number ofspecies. moderation is noticeablein it is that Although some recent times, certainly true there exist the haziest of ideas about the number of in either only exact species genus. Hennings in 'Die natiirlichen Pflanzenfamilien'(1898: 149) held the opinion that bekannte denen in Irpex comprized "Gegen 70 Arten, von etwa 12 Deutschland und Osterreich vorkommen." In the second edition of this serial work Killermann (1928: 166) stated that the same genus contained "Etwa 50 Arten, einige in Mittel- europa." This is also the numberofspecies quoted by Ainsworth & Bisby (1943: 149). it dawn that after Gradually, however, began to Irpex was not so large a genus all, and the number of Ainsworth species accepted by (1971: 294) was subsequently reduced to 20. Which are the criteria that mark a species as a member of Irpex ? To answer this question it appeared necessary to analyse the type species, Irpex lacteus, and in order to carry out the analysis it was necessary to indicate a neotype for this species. Only then was it possible to decidewhether or not all the species that had been referred to this Irpex really belonged to genus. The situation in Steccherinum was somewhat different in that here, apart from analyzing all the species that had been wrongly placed, the literature had to be searched for possibly unrecognized members. To judge the pertinence of a species from is On the other the indiscriminate an inadequate description not easy. hand, of As result the of borrowing specimens for study is impossible. a types perhaps too asked loan that turned have relation all Steccher- many species were on out to no at to while most members of the still remain in inum, probably some unrecognized genus their covers, uninvestigated. The of this clear the table ofall the clutter mixed aim work has been mainly to up with and overgrowing the few species which are true members of Irpex and Steccher- inum. It may be regarded as highly unsatisfactory that in the process so many specific for their epithets landed in a vacuum, they were not guided to pertinent generic names. This is unfortunate but unavoidable. The word "Studies" in the title ofthe present paper has been chosen intentionally, for the work is not a monograph. Too many of the collections seen have been left unidentified. It is inconceivable that these should undescribed represent species. Rather must it be assumed that they are unrecognized forms of known species, concealing their identity under a disguise that will remain impenetrable as long as the extent of the variability is not understood. It is felt that an author, recognizing his should leave it his other locked doors. limitations, to successor to try keys to open I am deeply indebted to the directors and/or keepers of the following herbaria indicated the usual for the loan of material other valuable col- by symbols type or MAAS GEESTERANUS: Irpex and Steccherinum 445 lections: Amsterdam (AMD), Auckland (PDD), Beltsville (BPI), Cambridge, U.S.A. (FH), Chapel Hill (NCU), Firenze (FI), Gainesville (FLAS), Geneve (G), Helsinki (H), Ithaca (CUP), Kew (K), Kobenhavn (C and CP), La Plata (LPS), Leningrad (LE), Montpellier (MPU), Miinchen (M), New York (NY), Padova (PAD), Paris (PC), Philadelphia (PH), Porto Alegre (PACA), Praha (PR), Provi- dence (BRU), Stockholm (S), Tokyo (TNS), Uppsala (UPS), Zurich (Z). Grateful acknowledgment is also made to Dr. G. Bohus (Budapest), Mrs. M. Tortic (Zagreb), and Dr. G. Malengon (Valognes) for various information. Special thanks are given to Dr. O. Fidalgo (Sao Paulo) for generously providing Xerox copies of some of Rick's rare publications. GENERAL PART Macroscopic characters. — Most of the macroscopically visible charac- ters do not require special discussion. Theirnature will be apparent from the specific descriptions. It is necessary, however, to point out their great variability, depending environmental and sometimes the of the basidiome on age, conditions, position relative to the substratum. Some little used characters, like the aspect of the ad- hymenial surface (i.e. the surface from which originate the spines) and of the sides of the have been resorted in the spines, to an attempt to distinguish species more easily but here again the changes that develop with age often introduce further difficulties. It is this wide variability of almost all characters that has resulted in the failure thus far to construct a satisfactory key. Some words must be said about the terms used in describing the aspect of the spines. These terms have all been borrowed from Lawrence (1958: 746-747), who them the various of hairiness in vascular It is applied to types plants. perhaps super- fluous to point out that the 'hairiness' of the spines in Steccherinum is brought about by the protruding cystidia. Special mention should be made of the colour terminology. There are several available their usefulness with colour charts at present but decreases proportionally the diminishing of the colour area to be defined. Particularly the colour zones in Steccherinum may be so narrow as to reduce the colour-evaluation to mere approxi- standardized mation. In such cases the use of symbols or terms would pretend a perfectly unjustified precision. The colours indicated, like all other macroscopic features, refer to those of the dried material. As a rule the colour of the context in dried materialof both Irpex and Steccherinum be value is white to pallid. Deviating colours are likely to regarded as of diagnostic but this is seldom the The dark brown which in S. ochraceum the case. layer separates firmer context from the tomentum does not mark a new species but simply indicates of On the other the discolouration of the the advanced age the basidiome. hand, context of S. reniforme and the way it advances with age characteristically separate this species from S. rawakense. PERSOONIA Vol. Part 446 7, 4, 1974 Chemical data. — As far as known no chemical analyses exist of either Irpex Steccherinum. Not of these has been mentioned in the or a single species genera more works deal with recent which, exclusively or partially, fungal chemistry (Shibata & Yet from the several of al., 1964; Birkinshaw, 1965; Turner, 1971). way species Steccherinum discolour on drying or in the herbarium, whereas others remain practic- it is that there be certain chemical differences. ally unchanged, apparent must Hyp hal construction. — Whereas there is no special need to discuss the hyphal structure in Irpex, something must be said of the construction in Steccherinum. Steccherinum The context in has been described as dimitic, consisting of generative and skeletal This hyphae (Maas Geesteranus, 1962: 403). description now turns out to be for in certain and in certain oftheir third kind incomplete, species parts context a of be which hyphae may found, would cause some authors to regard these species trimitic. It is in connection with of the as particularly recent developments concepts 'dimitic' and 'trimitic' that the context of Steccherinum ochraceum was reinvestigated in greater detail. The two collections chosen for the examination are (1) U.S.A., Whitehouse M. M. A. Donk Michigan, Landing, 9 Sept. 1969, J. Larsen 3658 & and Oct. 142 11 (Herb. Donk, L) (2) Netherlands, Utrecht, Oud-Loosdrecht, 29 1966, J. Daams (L). In both collections the basidiome consists of well-developed reflexed as well as effused portions. COLLECTION 1 : In the context ofthe pileate portion, more especially in the region where the about the have hyphae are to enter spines, a reorganization appears to taken place. Some of the generative hyphae become moderately thick-walled, while others much kinked develop very branched, highly tortuous and hyphae of limited Thethick-walled kind of these latter could well be termed 'bind- growth. hyphae very ing hyphae' (Corner, 1932a: 74) or'ligative hyphae' (Pouzar, 1966a: 171). However, what name should be given to those that show an occasional clamp-connection, and to others which are equally twisted but thin-walled and filled with oleaginous matter? The skeletal in this while branched.