66. Cladosporium gentianae Lobik, Bolezni Rast. 17(3-4): 189. 1928. Figs 140, 141.

Holotype: Russia, on leaves of Gentiana cruciata (Gentianaceae), 15 Sep. 1927 (LE 40527).

Lit.: Shvartsman et al. (1975: 95), Schubert (2005b: 81-83).

Ill: Lobik (1928: tab. 8, fig. 87), Schubert (2005b: 82, fig. 31, pl. 13, figs G-J).

In vivo: On living leaves, leaf sheaths and stems, leaf spots at leaf margins or starting at leaf margins and extending towards the mid, sometimes even covering the whole leaf surface, fading, turning yellowish brown, ochraceous, margin indefinite, somewhat raised at the border to the healthy leaf tissue, stems yellowish brownish discoloured, fading. Colonies amphigenous, solitary or in small tufts, effuse, scattered, loosely to moderately dense, caespitose, dark brown to blackish. Mycelium internal, subcuticular to intraepidermal; hyphae conspicuous, sparingly branched, 3.5-11 [micro]m wide, septate, sometimes distinctly constricted at the septa, subhyaline, pale olivaceous to medium olivaceous-brown, smooth or almost so to minutely verruculose, thick-walled, wall appearing yellowish, somewhat darker than the lumen and refractive, often with small to large, subglobose to somewhat irregular oil droplets, forming hyphal aggregations and stromata. Stromata substomatal to intraepidermal, small, subglobose, later somewhat flattened, 15-50 [micro]m diam, only few layers deep, usually composed of only few but large swollen hyphal cells, up to 20 [micro]m wide, subglobose to somewhat angular or irregular, medium to medium dark olivaceous-brown or brown, rarely pale olivaceous-brown, smooth to minutely verruculose, thick-walled. Conidiophores mostly loosely fasciculate, with 2-8 per fascicle, arising from stromata, sometimes solitary, arising from internal hyphae, emerging through stomata or erumpent through the cuticle, erect, rarely subdecumbent, more or less straight, cylindrical-oblong, robust, non-nodulose, usually not geniculate, unbranched, 26-120(-180) x (4-)5-10 [micro]m, septate, not constricted at the septa, dark olivaceous-brown to brown, minutely verruculose or somewhat irregularly rough-walled, walls thickened, usually distinctly two-layered, 1-1.5 [micro]m wide, slightly attenuated towards the apex, sometimes somewhat swollen at the base, protoplasm somewhat aggregated near the septa, which appear to be thickened, similar to distoseptation, occasionally enteroblastically proliferating. Conidiogenous cells integrated, terminal, occasionally intercalary, 13-36 [micro]m long, proliferation sympodial, with 1-8 conidiogenous loci, often crowded at the apex, protuberant, short cylindrical, subdenticulate, 1.5-2(-2.5) [micro]m diam, thickened, somewhat darkened-refractive. Conidia catenate, usually in branched chains, straight, subglobose, obovoid, ovoid, narrowly to broadly ellipsoid to subcylindrical, 3.5-23 x 3-6(-8) [micro]m, 0-1(-2)-septate, septum more or less median, not constricted at the septa, pale olivaceous-green to olivaceous-brown or brown, smooth or almost so to verruculose or irregularly rough-walled, walls thickened, up to 1 [micro]m wide, rarely appearing two-layered, often with a distinct, clearly delineated lumen, apex rounded or with up to 4 hila, slightly attenuated towards the base, hila protuberant, short cylindrical, 1-2 [micro]m diam, thickened, somewhat darkenedrefractive; microcyclic conidiogenesis not observed.

Substrates and distribution: On Gentiana spp. (Gentianaceae), Europe--Gentiana cruciata (Kazakhstan, Russia).

Notes: Lobik (1928) described and illustrated up to 3-septate conidia, which could not be observed. Cladosporium gentianae is the only species in this genus known to attack a member of the Gentianaceae. The seta-like, non-nodulose, very dark conidiophores and the conspicuous, often wide...