Biological Species in Pleurotus
INTERSTERILITY GROUP
Taxa Requiring Further Study
For purposes of this summary, some taxa which may be discrete are not taken up, for pertinent data are not available. Some are included below.
1. Pleurotus agaves Dennis.(1970) Kew Bull., Addition ser. 3: 466..(1970) Kew Bull., Addition ser. 3: 466.
Petersen used this name to represent what it is now known as P. opuntiae (see above). Vilgalys et al (1996) included this name as ISG XI (the epithet within quotation marks), but it is not the same organism as P. opuntiae (q.v.), on which the ISG was based. Diminutive basidiomata with dimitic stipe construction have been collected from central Florida to Costa Rica, and they seem to represent P. agaves. Compatibility experiments have not yet been performed.
2. Pleurotus bajocalifornica Esteve-Raventos in Moreno, et al. 1993. Mycotaxon 48: 452-453.
Moreno, G., F. Esteve-Raventos, and N. Ayala. 1993. A new species of Pleurotus from the San Felipe Desert (Baja California, Mexico). Mycotaxon 48: 451-457.
Nomenclatural history: A recent name with no recombinations.
Typification: MEXICO, northern Baja California, 26.X.1991, leg. Ochoa et al., AH 14575. (isotypes: SFSU, BCMEX).
Taxonomic history: Although micromorphological data were supplied (i.e. tissues monomitic), centrally-stipitate, monomitic taxa are unknown. No mention was made of a fugacious veil. Cultures are not available, so in toto, the organism is difficult to accurately place (see Petersen, 1995).
3. Pleurotus eugrammus (Montagne) Dennis. 1953. Kew Bull. 1953: 36, fig. 8.
Nomenclatural history: The epithet as used by Montagne is quite clear and seems to represent a discrete taxon in Pleurotus. Singer (1944, 1950) used his own interpretation of the epithet to serve as type of Nothopanus, but he misapplied the epithet. Thus (see Horak, 1968), Nothopanus is a taxonomic synonym of Pleurotus.
Typification (see Petersen and Krisai-Greilhuber, 1999)(holotype): CUBA, De la Sagre, date and collection unknown, as Lentinus eugrammus, annot. D.N. Pegler (PC). Also cited and illustrated by Horak (1968).
Taxonomic history: The species is known only from herbarium material, inhibiting comment on its genetic isolation history. Basidiomata are tough, dimidiate, dimitic and therefore are similar to those of P. djamor, which seems more delicate. Further investigation is required.
Genetic isolation: unknown
Mating system: unknown.
Self-cross: none.
Commentary: Although the type specimen was described by Horak (1968) and Petersen and Krisai-Greilhuber (1999), cultures of this species are not available, so it is not considered above. According to Petersen and Krisai-Greilhuber (1999) the species may be accepted as morphologically distinct, but similar to P. djamor. Guzmán (1983) reported it from the Yucatan Peninsula, but further investigation is needed to ascertain his use of that name.
4. Pleurotus fossulatus (Cooke) Saccardo. 1891. Sylloge Fungorum 9: 49.
Nomenclatural history: M.C. Cooke was credited with this epithet by Aitchison (1888. Trans. Linn. Soc., Bot. II, 3: 128), but placed within Agaricus. Saccardo recombined the epithet in Pleurotus.
Typification (holotype, teste Pegler. 1976): AFGANISTAN, Kabul Prov., Badghis District, 5.III.1885, Aitchison no. 115 (K).
Taxonomic history: Basidiomata are subeccentrically to almost laterally stipitate, with pileus surface deeply cracked or areolate. With no mention (Pegler, 1976) of tissue miticity or absence of partial veil, it is difficult to place the organism.
5. Pleurotus mexicana Guzmán. 1974. Bol. Soc. Mex. Mic. 8: 84.
Typification (holotype, viz. Guzmán, 1974): MEXICO, zona de Chichotla, date unknown, coll. Johnson, no. 1973-060362 (ENCB; isotype TRTC).
Commentary: With no comment on presence or absence of skeletal hyphae it is difficult to place this species. Its form, color and topotype all indicate one of the color forms of P. djamor.
6. Pleurotus parsonsii G. Stevenson. 1964. Kew Bull. 19: 31.
Typification (holotype): NEW ZEALAND, North Island, Wellington, Levin, 20.XI.48, coll. E. Parsons, Stevenson 461 (K).
Commentary: The synonymy offered by Segedin et al. (1995) is doubtful, and no culture data are available. The report by Segedin et al. (1995) of P. parsonsii on Cordyline, thin pileus flesh, yellow pileus color, and repeated observations of "tapering sclerified [hyphal] ends" in tramal tissue (which may be construed as skeletal hyphae), suggest that P. parsonsii may be a synonym of P. djamor, verified from New Zealand too late for inclusion in the paper by Segedin et al..
7. Pleurotus velatus Segedin et al. 1995. Austral. Syst. Bot. 8: 477.
Typification (holotype): NEW ZEALAND, North Island, Waitakere Range, Bethells Beach, 21.V.78, PDD 59757.
Commentary: Basidiomata are eccentrically stipitate and form a fugacious partial veil. Stipe tissue is dimitic. These characters place the species near P. dryinus, to which Segedin et al. make comparison.