On the type of Coprinus pachyspermus
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Original description

Coprinus pachyspermus P.D. Orton, sp. nov. Fig. i, j-1. A habitu robusto, basidiis bisporigeribus et sporis lentiformibus permagnis facile distinguitur. Pileus ovoideo-ellipsoideus interdum admodum acutus, 6-30/4-18 mm, dein expansus saepe umbonatus demum revolutus, (5)10-45 mm, griseus vel cremeo-griseus, primo toto minute farinosus vel praecipue ad discum crasse ± acute verrucoso-floccoso interdum ad verticem brunneotincto squamulosus, ad marginem denique radialiter fissuratus. Lamellae anguste adnatae, e griseo nigricantes, subconfertae, L = 20-30(40), l =1-3, ad aciem primo albo-floccosae. Stipes 30-110/1-4 mm, fere aequalis vel deorsum leviter incras-satus, ad apicem minutissime floccoso-punctatus, ad basim interdum farinoso-squamulosus, cavus. Caro tenuissima, pallide grisea. Odor nullus.
Sporae forte lentiformes, ellipsoideae vel leviter ovoideae aut subglobosae vel obscure globoso-sexangulatae, (14)15-17/8.5-10/12.5-14 µm (Fig. l), in cumulo umbrinonigrae. Basidia 2-sporigera. Cystidia aciei lamellarum ± globosa vel pyriformia, interdum ± clavata, 30-50/28-37 µm. Cystidia faciei lamellarum clavata vel elongato-vesiculosa, 80-200/32-74 µm. Cellulae veli globosae vel rariore leviter ellipsoideae, hyalinae, interdum incrustatae, 18-90 µm latae, hyphis angustis hyalinis 2-4 µm latis conjunctae. Inverness-shire. Nethy Bridge, ad fimum vaccinum, 28 viii 1969, Orton 3555 (holo. E).

Cap ovoid-ellipsoid sometimes with rather pointed apex, 6-30/4-18 mm, then (5)10-45 when expanded and often slightly umbonate with revolute or inrolled margin, grey or creamy-grey, at first from entirely minutely mealy to coarsely often ± pointed warty floccose-scaly especially at centre, scales sometimes (especially in larger specimens) darker sepia-brownish at tips, margin becoming radially split or rimose. Gills narrowly adnate, grey then blackish, fairly crowded, L = 20-30(40), l = 1-3, edge white flocculose when fresh. Stem 30-110/1-4 mm, ± equal or slightly thickened in lower part, white or hyaline, more rarely hyaline-grey, finely white silky-floccose in lower part, apex very minutely floccose-punctate, base sometimes with traces of veil as on cap, hollow. Flesh very thin, grey-horn colour. Smell none. Spore-print blackish-umber.
Spores strongly lentiform, ellipsoid or slightly ovoid in side-view, subglobose to indistinctly rounded-hexagonal in face-view, (14)15-17/8.5-10/12.5-14 µm (Fig. l). Basidia 2-spored. Marginal cystidia ± globose to pyriform, a few ± clavate, 30-50/28-37 µm. Facial cystidia clavate or elongate-vesiculose, 80-200/32-74 µm. Cells of veil on cap globose or more rarely slightly ellipsoid, hyaline, sometimes encrusted-crystalline, 18-90 µm in diam., joined to narrow hyaline hyphae 2-4 µm in diam. Inverness-shire. Nethy Bridge, on old cow dung, 28 viii 1969, Orton 3555 (holo. E).
Uncommon, as yet only known from the type locality. Readily recognised microscopically by 2-spored basidia and large lentiform spores; variable in si^e but often rather robust and very coarsely floccose-mealy-scaly.

j-l, C. pachyspermus Orton: j, large, young warty-scaly fruit-body; k, small young finely-floccose fruit-body; I, spores.
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