Pileus 1-3.5(-4) cm broad; pale watery brown or pale dingy yellow brown (smoky brown, pale “buckthorn brown,” pale “snuff brown”), hygrophanous and fading to a pale dingy tan or brownish gray or pallid; convex at first with an incurved margin, becoming broadly convex, finally plane with the disc shallowly depressed, sometimes deeply depressed in age; margin long striate when moist, opaque in faded specimens; surface typically glabrous, surface fibrils sometimes becoming diffracted in age and then appearing squamulose; context (sic) thin and fragile, pallid. No odor or taste.
Lamellae broadly adnate to short decurrent, moderately broad to broad (up to 4 mm), close or subdistant, white or becoming dingy tan or avellaneous in age.
Stipe 1-3(-6) cm long, apex 1-3 mm thick, equal, surface glabrous, translucent, concolorous with pileus or pallid, solid.
Spores 5.5-7 X 4-4.5 µm (4-spored basidia; up to 11 X 7 µm from 2-spored basidia), ellipsoid, verruculose, deposit white. Basidia 19-27 X 4-8 µm, usually 4-spored but sometimes also 2-spored. Cheilocystidia numerous on some lamellae but rather scattered on others, 33-62(-100) µm long, protruding 15-47 µm beyond hymenium, 5.5-11 µm diam; subcylindric or rather fusoid ventricose, apices obtuse, rounded or subcapitate, smooth, hyaline, walls thin. Pleurocystidia of same type as cheilocystidia but less numerous and very scattered along faces of lamellae. Pileus: cutis brownish in KOH, pigment very finely encrusted on hyphal walls, hyphae cylindric or slightly inflated, 1.5-7 µm diam; context (sic) brownish or hyaline in KOH, hyphal walls finely encrusted or more often smooth, hyphae cylindric or inflated, 2.5-20 µm diam. Hymenophoral trama of parallel hyphae, hyaline in KOH, hyphae cylindric or inflated, 6-13(-27) µm diam, walls usually smooth. Clamp connections present.
Gregarious or subcespitose. On or near Peltigera and other lichens, in sandy soil or moss. In the open or under spruce. June to October.
The genus Stachymophalina is proposed to accommodate Rhodocybe striatula Kühner and any other small species of the Tricholomatacea which have inamyloid verruculose spores. The presence of clamp connections, lamellar cystidia, and encrusted pigments are considered to be of secondary importance.
As illustrated by Figs. 1, 2, and 3, there is a distinct difference between the spore surfaces of Fayodia and Stachyomphaline striatula. Not only does S. striatula lack an ectosporium but the ornamentations are as dissimilar as between a Russula and a Melanoleuca! There has not been an examination of the wall in section of S. striatula as far as I have been able to determine, but under the oil immersion objective the wall below the ornamentation appears thin and without the multiple layers found in F. gracilipes by Besson (1969). While it is not difficult to relate F. gracilipes and S. striatula on most features of the basidiocarp, it seems to me that the different spore morphologies do not support either a direct relationship to one another or a common ancestry.
The spores of S. striatula are likewise not like the irregular nodulose spores know for Mycenella nor the smooth thick-walled spores of Myxomphalia. Omphaliaster has nodulose spores with narrow ridges between the protuberances (Bigelow and Rowley, 1968, Fig. 7, as Clitocybe asterospora) and Rhodocybe has spores which are angular in end view and undulate-pustulate in side view (T. Baroni, personal communication). In Clitocybe (ss. meo, Lepista ss. aut auct.) some species have spores with inamyloid verruculae which are larger, and it would not be difficult to postulate some relationship if only the spores were considered. However, the basidiocarps of Clitocybes which possess ornamented spores are much fleshier in the pilei and stipes than S. striatula. There are pigment differences as well, and the type of cystidia found in S. striatula is very atypical of Clitocybes.
The ornamentation of S. striatula appears to be finely echinulate under the oil immersion objective, but Fig. 3 (Horak 70/578) illustrates that the ornamentation actually consists of verruculae. The spores of several other collections of S. striatula and the type of Mycena cineraria were studied with the scanning electron microscope and found to be indentical to those of the European specimen. Singer (1972) reported that the outer spore layer and ornamentation (as Fayodia striatula) were distinctly cyanophilic. This is possible, but I am uncertain of the localization of the stain from tests on the spores of several collections. Unfortunately, the contents of the spores pick up the stain readily and obscure the amount which may be concentrated in the wall. Even in spores which were ruptured or with plasmolyzed contents, the tests were indecisive due to the thin walls and minute verruculae.
Stachyomphalina striatula is sometimes found under the name Fayodia leucophylla (Gillet) M. Lange & Silvertsen. It is debatable if the latter epithet is applicable to the species described here as S. striatula. The situation has been discussed by Lange and Silvertsen (1966).