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Toninia subdispersa (Nyl. ex Hasse) K. Knudsen (redirected from: Lecania subdispersa)
Family: Ramalinaceae
[Lecania subdispersa (Nyl.) Hasse]
Toninia subdispersa image
Bruce Ryan  
Thallus: crustose, rimose-areolate to areolate, effuse, thin (c. 0.3 mm thick) areoles: often well-developed, angular to irregularly round, tightly attached, verruculose, sometimes somewhat granular, up to c. 1 mm across surface: light gray to yellowish gray, unchanged when wet, the edges concolorous with the center, plane to slightly verrucose, dull, epruinose cortex: not developed, upper layer of thallus composed of intricate hyphae cells, containing clusters of rather small crystals, clusters up to 15 µm wide medulla: indiscernible; algal layer: not clearly differentiated, algae: 5-12 µm in diam Apothecia: numerous, adnate to sessile, up to 1.2 mm in diam. disc: deep or dark brown to brownish black, scarcely changed when wet, plane to slightly or moderately convex, dull, epruinose margin: thalline, concolorous with thallus, thick when young (0.1-0.2 mm wide), raised at least when young, becoming subcrenate, finally excluded amphithecium: thin, not well developed, sometimes a cortex with conglutinated paraplectencymatuous cells present, rarely with a small epinecral layer up to 20 µm thick, outer rim pale brown, or with algal cells filling the entire margin parathecium: often appearing as a dark rim giving the apothecia a lecideine appearance, often well developed, up to 120 µm wide at the outer rim, paraplectenchymatous, with cell lumina 2-4 µm wide, conglutinate epihymenium: dark reddish brown, K+ reddish-brown intensifying, with a few or without granules, 20-30 µm thick hymenium: hyaline below, 50-80 µm tall; paraphyses: coherent, simple, 1.5-2 µm wide, the tips clavate, 5-8 µm wide; hypothecium: hyaline to pale yellow, up to 200 µm high asci: narrowly clavate, 60-65 x 15 µm, 8-spored ascospores: hyaline, simple to 1-septate, oblong-ellipsoid, 16-22 x 4.5-5 µm Pycnidia: immersed, the upper part visible and concolorous with apothecia, 50-100 µm in diam; conidiogenous cells: simple, rarely branched basally, elongate to clavate, 5-10 x 2-2.5 µm conidia: filiform, slightly to strong arcuate, 12-20 x Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on sandstone and rarely on soil, rarely on bone, thallus sometimes infected with black apothecia of Toninia talparum World and Sonoran distribution: Channel Islands in southern California. Notes: There appear to be several taxa involved in material identified by Hasse as Lecanora (or Lecania) subdispersa: 1) Thallus subsquamulose, brown, disc black; 'margin' [presumably the thalline one] indistinct or absent, spores 10-12 x 5 µm, [= Lecanora subdispersa 'Nyl.' ex Hasse (1898: p. 12); no material seen by us that both fits this description and is labeled as L. subdispersa; the identity is uncertain due to the vagueness of the description, but it does not belong to L. subdispersa sensu Nyl. (see below) because of its short spores, and probably not to L. brunonis because of its black discs and because, according to Hasse (1898 & 1913), at least in the "type specimen", from the "type locality" of "Stone Canyon" in the Santa Monica Mountains (no material from this locality seen by us) L. subdispersa is mixed with sterile thalli presumed by Hasse to belong to L. brunonis]; 2) thallus subsquamulose, gray; disc +brown, "margin" paler than disc, finally excluded, spores 9-13 x 3-4.5 µm. [= Lecania subdispersa ('Nyl.' ex Hasse) Hasse (1913: p. 97); basionym cited by Hasse as "Lecanora subdispersa Nyl.; Hasse, Lich. South. Calif. 12. 1898"; no material fitting this description and identified by Hasse as L. subdispersa seen by us; the identity is uncertain, but the thallus color is wrong and the spores are too narrow for L. brunonis]); 3) thallus subsquamulose, brown, with thick cortex, disc +brown, amphithecium finally excluded; parathecium thin and inconspicuous, paler than disc, spores 16-20(-26) x 4-6 µm [= Lecania toninioides; Hasse 897 (MIN, pr. max p.), US, pr. p.]; 4) Thallus areolate, white, without a cortex, disc +brown; parathecium not evident [Hasse 480 (H-Nyl)] or distinct and paler than disc [Hasse 897 (US, pr. p.; MIN, pr. min. p.)], spores 16-20(-22) x (3-)4-5 micrometer; [Lecanora subdispersa Nyl. in herb., which = Nyl. ex B.D. Ryan; Note: non-Hasse material included by us under this species often has a conspicuous parathecium darker than the disc]; 5) thallus subsquamulose, brown, with thick cortex, disc brown, amphithecium soon excluded, parathecium absent or inconspicuous (?), spores 10-15(-18) x (4-)5-6 micrometer. [= Lecania brunonis; no material definitely belonging to L. brunonis has been seen by us in material identified by Hasse as L. subdispersa] The following nomenclatural actions (with references to the provisions of the latest edition of the International Code of Botanical Nomenclature [Greuter et al. 2000]) are made in the present treatment: 1) lectotypification of the basionym Lecanora subdispersa Nyl. (Art. 9.9) based on a specimen definitely known to have been seen and annotated by Nylander, the author to whom the name was attributed by Hasse; 2) publication of Lecanora subdispersa Nyl. ex B.D. Ryan (Art. 46.4), as a new name (Art. 7.4) for the species thus lectotypified; 3) publication of a new combination in Lecania by B.D. Ryan (Art. 7.4), based on this new basionym; 4) an emendation of the circumscription of the species (Art. 47.1 and Rec. 47A) by B.D. Ryan with a new diagnosis that reflects the characters of the lectotype, rather than that of the diagnosis and subsequent description by Hasse, which at least at present cannot be definitely associated with any specimen we have seen nor (due to the vagueness and somewhat contradictory nature of Hasse's diagnosis and description) with any species, of which we know. Lecania. subdispersa is characterized by its white to pale yellowish gray thallus, containing clusters of rather small crystals, the absence of a cortex and epinecral layer, its relative long ascospores and its preference for sandstone. Other species in the Sonoran region, with which it might be confused, are: L. toninioides, that differs by the following characters: thallus squamulose, yellowish to grayish brown or yellowish gray, the edges of squamules paler than the rest, upper cortex to 50 µm thick, composed of mostly anticlinal hyphae; epinecral layer 15-25µm thick, sharply delimit