Basidiospore Form in the British Species of Lepista and Ripartites (Agaricales)

Abstract

Summary. An account is given of spore form and structure in the genera Lepista and Ripartites (Agaricales) together with an atlas of transmission and scanning electron micrographs. Lepista (Fr.) W. G. Smith is a small genus with an essentially temperate distribution, although also occurring in the tropics. Singer (1962: 239) recognized nineteen species on a world basis. Six British species are cited in the New Check List (Dennis, Orton & Hora, 1960: 10oI-o02). In the present study nine species are included. Although Lepista is a small genus, it is well known because of the occurrence of a number of edible mushrooms, particularly the wood blewit, L. nuda (Bull. ex Fr.) Cooke and the blewit, L. saeva (Fr.) P. D. Orton in North Temperate regions, and L. caffrorum (Kalchbr. & MacOwan) Singer in South Africa. Species of Lepista may be defined as agarics with tricholomatoid or clitocyboid basidiocarps which bear clampconnexions on the hyphae and produce ornamented, hyaline, inamyloid but cyanophilous spores forming a pinkish spore print. Ripartites P. Karst. is a closely related genus which produces an olivaceous brown spore print. Only two species of Ripartites, R. tricholoma (Alb. & Schw. ex Fr.) P. Karst. and R. metrodii Huijsm. are recognized in the British Isles. The name Lepista was first introduced by Fries (1838: 315) as a tribe of the genus Paxillus Fr. with the following diagnosis: Hymenophorum griseo-carneum, trama simulari. Lamellae fragiles. Sporidia sordida et totius fungi color ex albido sordidus. Three species were included, the first being Paxillus lepista (Fr.) Fr. A second unnamed tribe was placed in Paxillus by Fries (1863: 31o) together with the following diagnosis: Tricholomata quaedam, sporis sordide albidis et lamellis facile secendentibus v.c. A. cinerascens, personatus, nudus etc. ad hoc genus referenda censeo novamque sistunt tribum, cum Agaricis Tricholomatibus analogam, ut Lepistae cum Clitocybis. When Smith (1870: 248) raised Lepista to generic level, the whole of Fries's original tribe was included, together with the later unnamed taxon. According to Singer (1951 a: 456) the type species, Paxillus lepista sensu Bresadola, is Lepista subaequalis (Britzelm.) Singer, and Bresadola's interpretation appears to coincide with an original plate made under the direction of Fries. Maire (1913: 338) proposed a new genus, Rhodopaxillus for acystidiate species of Tricholoma (Fr. ex Fr.) Staude with pink verrucose spores, covering the original tribe described by Fries. Four species were included: R. panaeolus (Fr.) Maire (= L. luscina (Fr. ex Fr.) Singer), R. saevus (Fr.) Maire, R. nudus (Bull. ex Fr.) Maire, and R. truncatus (Schaeff. ex Fr.) Maire (= Rhodocybe truncata (Schaeff. ex Fr.) Singer). However, Rhodopaxillus is antedated by Lepista (Fr.) W. G. Smith.