Summary:
Fieldmarks include 1) small pinkish rusty reddish to yellowish-brown stains that occur on all parts, 2) a white to buff, pale tan, or pinkish-tinged, dry or lubricous cap that is often darker or redder when old, 3) crowded, white to pale pinkish buff gills, 4) a whitish stem, 5) a mild odor, and 6) a tendency to grow on rotten wood. Lennox(1) describes a number of varieties in the Pacific Northwest. Rhodocollybia maculata var. maculata has a pallid to pale tan cap, whitish gills, rusty stains at least on cap and gills, a bitter taste, and round or nearly round spores measuring 5-7(8) x 4.5-6(6.5) microns. Var. immutabilis has a pale grayish cream cap up to 3.2cm across, gills colored as the cap or lighter, no rusty stains on cap, gills or stem, a mild taste, and ovate to elliptic spores measuring 6.5-8 x 4-4.5 microns. Var. nigra has a dark brownish black cap up to 4cm across, yellow to light orange gills, no rusty stains on gills and stem, a pleasant taste that becomes bitter, and elliptic spores measuring 7-8(8.5) x 4.5-5 microns. Var. scorzonerea has a pale buff to fulvous cap, yellow gills, sometimes yellow stem, rusty staining of cap, stem and sometimes gills, a bitterish taste (sometimes delayed), and elliptic spores measuring 7-8.5 x 4-5.5 microns (Halling says 5.6-7 x 3.5-4.2 microns). Var. fulva has a dark vinaceous brown cap up to 2.7cm across, white gills, rusty stains on gills and stem, a mild taste, and ovate spores measuring 5.5-6.5 x 3.5-4 microns. Var. occidentalis has a whitish cap sometimes with a pale pinkish or buff tinge, whitish to pale orange gills, rusty staining on cap, gills, and stem, a mild to slightly farinaceous taste (but Halling says bitter), and elliptic spores measuring 6.5-11 x 4-6 microns (Halling says 5.6-7 x 3.5-4.2 microns). The description here is derived from Lennox(1) is for var. maculata except where specified. Rhodocollybia maculata is common in the Pacific Northwest.

Cap:
4-9(12)cm across, (up to 15cm for var. scorzonerea), convex to obtuse, becoming flat, margin often wavy; pallid to pale tan, occasionally darker over disc, "stained faintly ferruginous in spots naturally or where bruised slowly"; moist or sublubricous but not truly hygrophanous or viscid, bald, (Lennox), (2.5)4-12cm across, "convex with incurved margin at first", becoming broadly umbonate to flat or wavy; typically white to buff, pale tan, or pinkish tinged, often darker or redder when old, especially at center, "and often developing rusty or reddish spots and stains", (Arora)

Flesh:
very thick, generally thicker than the depth of the gills at their point of attachment, "rather brittle when moist, soft when drier", (Lennox), thick; white; in stem colored as surface, (Arora)

Gills:
abruptly sinuate, appearing almost free when mature, crowded, blunt at stem and pointed toward margin, rather broad but not as broad as flesh is thick, 1.7-2.3cm x 0.6-0.9cm, ventricose [broader in middle], thin; white to pale pinkish-buff, staining ferruginous, especially along edges or where bruised, edges colored as faces; serrate to eroded, (Lennox), "adnate to adnexed or notched to nearly free, crowded"; white to pale pinkish buff, often developing rusty or reddish stains (like cap) when old, (Arora), crowded, narrow, thin; whitish to cream, yellowish white or pinkish, becoming red-spotted when old, (Trudell)

Stem:
4.2-10cm x 0.8-1.4cm, narrowing gradually to base then more or less rooting and narrowing abruptly in substrate, solid, rather firm but not tough, splitting easily longitudinally, sometimes flexuous [wavy] toward base; white, later sordid whitish, especially in lower half; base white-cottony-tomentose, upper part evenly white pruinose, fibrillose or with a thin appressed tomentum, becoming bald and longitudinally striate when old, (Lennox), 4-15cm x 0.5-2(3)cm, often tapered in lower part to form a more or less rooting base, "solid (at least when young), firm"; white to pale buff, usually developing rusty or reddish stains in lower part; smooth or fibrillose, (Arora)

Odor:
none or fungoid (var. maculata), mild (var. fulva), sweet, fruity (var. nigra), faint, somewhat fragrant, (var. scorzonerea), faint and sweet (var. immutabilis), faint, pleasant and aromatic or fruity (var. occidentalis), (Lennox)

Taste:
bitter (var. maculata, var. scorzonerea, var. nigra), mild to slightly farinaceous (var. occidentalis but Halling says var. occidentalis has bitter taste), mild (var. immutabilis, var. fulva), (Lennox)

Microscopic spores:
spores 5-11 x 3.5-6.5 microns (see NOTES for dimensions of varieties), broadly ovate to round, mostly nearly round (var. maculata) or ovate to elliptic (other varieties above), smooth, a small percentage dextrinoid (but in other varieties just called dextrinoid); basidia (var. maculata) 4-spored, 33-37 x 7-8.5 microns; pleurocystidia none, cheilocystidia (this for var. maculata, those of var. immutabilis and var. occidentalis absent, and those of other varieties vary in shape), generally abundant but inconspicuous, rarely exceeding basidia, 17-36 x 3-5 microns, "narrowly clavate, somewhat pointed, never really filamentous, thin-walled, not encrusted", (Lennox), 5-11 x 4-6 microns, round or nearly round in typical variety, elliptic in var. occidentalis, smooth, at least a few dextrinoid, (Arora)

Spore deposit:
creamy to pale peach or pinkish buff(Arora), cream (Lennox)

Notes:
It is found at least in WA (all varieties that are mentioned here), OR (var. maculata, var. scorzonerea), and ID (var. scorzonerea), (Lennox). There are collections from BC at the Pacific Forestry Centre and the University of British Columbia. R. maculata occurs in CA (Desjardin(6)). It is also found elsewhere in North America, and in Europe.

EDIBILITY

no because of frequently bitter taste, (Arora)

Synonyms and Alternate Names:
Collybia maculata (Alb.& Schwein.) P. Kumm.