Tricholomopsis ornaticeps (G. Stev.) E. Horak

Cooper, Jerry A. & Park, Duckchul, 2016, The fungal genus Tricholomopsis (Agaricales) in New Zealand, including Tricholomopsis scabra sp. nov., Phytotaxa 288 (1), pp. 69-76 : 73-74

Tricholomopsis ornaticeps (G. Stev.) E. Horak

The following description is emended from Stevenson (1964), Horak (1971), and examination of New Zealand collections, including the holotype, enumerated in Table 1.

Macro-morphology:―Pileus 70–80 mm diam., convex with down-rolled margin becoming centrally depressed, ochraceous to saffron yellow, thickly covered with minute brown fibrillose scales. Lamellae moderately distant, attachment sinuate, yellow, staining brown at edges. Stipe 30 × 10 mm, creamy above, ochraceous at base, fibrillosestriate. Context creamy yellow in pileus and continuous with stipe. Spore print white. Gregarious on ground and associated with decaying wood.

Micro-morphology:―Spores oval to subcylindrical, neither amyloid nor dextrinoid, hyaline, thin-walled, with hilar appendage, length 8.3 μm (σ = 0.54) × 4.3 μm (σ = 0.32), Q = 2.0 (σ = 0.16), n = 20. Basidia 20–40 × 8–10 μm, narrowly clavate, 4-spored. Lamella edge sterile. Cheilocystidia conspicuous, thin-walled, some with yellow plasmatic pigment in KOH, 30–100 μm long × 10–30 μm diam., multi-septate, constricted at septa and often appearing like chains, terminal cells obovoid to broadly cylindrical. Clamp connections present in all tissue. Pleurocystidia absent. Pileipellis a cutis of loosely woven hyphae about 5 μm diam.; scales are aggregations of parallel hyphae 3–5 μm diam., with thickened walls which are rusty brown in transmitted light.

Habitat and distribution:―occasional in North Island and upper South Island in native beech forest, and in exotic conifer plantations of Pinus radiata and Larix spp .

Comments:— T. ornaticeps ( Fig. 3 ) is easily distinguished microscopically by its elongate spores and cheilocystidia often appearing to be chained. Macroscopically it is distinguished from T. rutilans by the lack of plum colours, and from T. scabra by its less scabrous pileus and occurrence in beech forest and plantations.

Figures

FIGURE 3. Tricholomopsis ornaticeps. A) water colour (G.M. Taylor), PDD 84171, scale 15 mm; B) cheilocystidia (composite image), PDD 82501, scale = 75 μm; C) spores (composite image), PDD 84171, scale = 20 μm; D) cheilocystidia, PDD 102517, scale = 40 μm. Photos: B, C, D by Jerry Cooper.