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Summary: features include large, yellow to yellowish brown, viscid cap that becomes prominently tuberculate-striate, pale yellow gills that often stain brownish but do not change when injured, and sometimes have edges beaded with moisture, yellowish white stem that stains brownish, almond-like to fetid odor, and microscopic characters including spores 6.3-9.0 x 5.7-7.7 microns, with warts and short to long ridges both up to 0.3-1.0(1.4) microns high; a member of the Russula fragrantissima group, which also includes R. laurocerasi and R. foetens, but exactly which members of this group occur in the Pacific Northwest is unclear; Shaffer says his description differs from Romagnesi (1967) description that gave cap cuticle as separable only at the very margin, and spores as 7.5-10 x 7-9.2 microns with ornamentation up to 1.6 microns high, Phillips, whose description is similar to Shaffer's also says "This species as defined in America differs markedly from European collections", Shaffer also notes "This species is the common mushroom with large basidiocarps and strong odor usually called Russula foetens in the United States. It differs from R. foetens in the sense of Schaeffer (1952) and Romagnesi (1967) in its distinct benzaldehyde odor, which is present at least during the early stages of basidiocarp development, and its spore ornamentation, which resembles that of R. laurocerasi in pattern but is lower." [Latin names italicized]; not included in Pacific Northwest key of Woo(1) or reported by Grund(2) from Washington, Thiers gives R. fragrantissima Romagnesi from CA (including the northwest next to Oregon) with cap cuticle separable 1/2 to 2/3 the distance to the disc, spores 8-10.5 x 6.7-9.5 microns, and ornamentation 0.8-1.2 microns, and notes, "It has now been suggested that the North American species may prove to be distinct" [from R. foetens and R. fragrantissima Romagnesi]; C. Roberts (pers. comm.) says that the species usually found on Vancouver Island in BC has features intermediate between R. fragrantissima and R. laurocerasi, and she reports collections in her thesis as R. fragrantissima Romagnesi sensu Shaffer, with the note "Vancouver Island collections agree on most characters, particularly the spores, with Shaffer's 1972 description of North American material, to which the reader should refer for additional information. Local collections peel only at the margin as in Romagnesi's description, rather than up to 3/4 as in Shaffer's, the vascular hyphae and pseudocystidia do stain in SV, and the flesh is peppery, characters associated with Shaffer's 1972 description of North American Russula laurocerasi. Shaffer also notes that he made collections that had some characters of both R. fragrantissima and R. laurocerasi"; collections at Oregon State University from Oregon labeled as each of the three species, CHEMICAL REACTIONS color reactions on cap cuticle (except where noted): 10% FeSO4 grayish yellowish pink to light reddish brown, 2% phenol dark brown or dark grayish reddish brown, formalin colorless, 30% ammonia no change on cap flesh, SV light purplish gray or bluish gray, guaiac quickly grayish green or deep bluish green, 30% KOH pale to light yellow or moderate yellowish pink, (Shaffer)
Cap: 7-20cm across, somewhat spherical, slowly expanding with incurved margin, thick, fleshy; "pale yellow to yellow-brown or tawny; very viscid when wet, shiny when dry, tuberculate-striate at margin", (Phillips), 7.5-20cm across, nearly spherical to oval when young, then pulvinate [cushion-shaped] with an incurved margin, later pulvinate to convex to flat with or without a depressed disc, when old irregularly concave or somewhat funnel-shaped, at times split or lobed marginally; when young pale yellow to moderate yellow, grayish yellow or light orange yellow to yellowish brown, often becoming at least partly darker when old, sometimes even grayish brown, dark grayish reddish brown or dark grayish yellowish brown; strongly viscid and shiny when wet, moderately to scarcely so in dry weather, bald, often minutely streaked outward from disc, separable 1/3 to 3/4 the cap radius, becoming prominently tuberculate-striate 0.6-3cm from edge inward, (Shaffer)
Flesh: hard; white, (Phillips), 0.2-0.7cm thick at mid-radius, hard, later firm-brittle; "yellowish white to pale yellowish brown, often stained moderate brown or strong or moderate to dark yellowish brown around larval channels, unchanging when cut", (Shaffer)
Gills: adnate, close, narrow near margin; pale yellow, stained brown where injured; "often beaded with moisture on margin when young", (Phillips), adnexed to adnate, close to subdistant, equal or unequal with subgills varying in frequency and length, but mostly reaching halfway or more to stem, 0.6-1.7cm broad, acute to subacute near margin, occasionally forked at or near stem and sometimes outward, interveined; "yellowish white when young, remaining so or becoming pale yellow to pale orange yellow, sometimes assuming a gray tinge, often stained moderate brown or moderate to deep yellowish brown, unchanging when injured"; entire, the edges sometimes beaded with moisture when young, (Shaffer)
Stem: 7-15cm x 1.5-6cm, "equal, firm, soon hollow; colored as cap, staining darker brown; dry, dull", (Phillips), 7-15cm x 1.5-6cm, may be flared at top, otherwise more or less equal, subfusiform [somewhat spindle-shaped], narrowing to base which may appear pinched, or enlarging to broadly rounded base, solid becoming hollow; "yellowish white, often stained strong brown or moderate to dark yellowish brown basally, or becoming light grayish brown, light grayish yellowish brown, or moderate yellowish brown almost overall"; dry, dull, puberulent [downy] to minutely scurfy at top when young, otherwise bald, scarcely longitudinally rugulose [wrinkled], (Shaffer)
Odor: fetid to almond-like, rarely very fragrant in North American collections, (Phillips), of benzaldehyde [almond-like] and sometimes also somewhat fetid when young, often becoming more strongly fetid and the benzaldehyde odor decreasing or disappearing with
Taste: oily-peppery, (Phillips), tasteless or slightly peppery or oily-peppery, (Shaffer), pleasant (Miller), very unpleasant, usually bitter and pungent at first, then peppery, (Thiers)
Microscopic spores: spores 6-9 x 5.5-7.7 microns, warts up to 1 micron high, with partial to complete reticulum, (Phillips), spores 6.3-9.0 x 5.7-7.7 microns, broadly elliptic, broadly obovate, broadly ovate, or nearly round, ornamentation of conic to cylindric warts and short to long ridges, both up to 0.3-1.0(1.4) microns high, and connectives, "varying from mostly isolated warts and short ridges to a partial or nearly complete reticulum of ridges, warts, and connectives with interspersed isolated warts and short ridges, the ridges often alternately amyloid and nonamyloid"; basidia 36-66 x 8.5-11.9 microns, clavate, usually 4-spored, rarely fewer-spored; hymenial pseudocystidia abundant, (40)51-100 x (5.4)6.2-13.6 microns, arising in inner subhymenium or in trama, embedded or more usually projecting up to 45 microns beyond basidioles, "subcylindric, clavate, fusiform, or fusoid-clavate", "often capitate, papillate, or (moniliform-)appendiculate, otherwise simply rounded apically", often "extruded-inflated" apically, straight, curved, sharply bent, or even tortuous basally, SV+; cap epicutis 50-60 microns thick (subcutis 200-520 microns thick), with gelatinous matrix, a trichoderm of non-gelatinous, branched, colorless connective hyphal ends 1.7-4.5 microns wide, whose apical cells are subcylindric, narrowly clavate, narrowly fusiform, or subulate, also with common pseudocystidia that are 32-90 x 4.5-9.0 microns, "subcylindric, clavate, or fusiform, and sometimes capitate, have SV- or weakly SV+ granular contents, and arise in the epicutis or subcutis as the apical cells of hyphae otherwise connective in nature", the hyphal ends often inconspicuous in mature fruitbodies, (Shaffer), spores 8-10.5 x 6.7-9.5 microns, often round, rarely nearly round, ornamentation "of scattered heavy warts with broad, dark, heavy ridges and fine lines often forming a partial or nearly complete reticulum, some inamyloid warts also present", warts 0.8-1.2 microns high; basidia 2-spored and 4-spored; hymenial cystidia common to scattered, 50-80 x 5-8 microns, not projecting from hymenium or only slightly projecting, "clavate to cylindric, with narrow, tapered, sometimes strangulated apices", colorless to pale yellow-brown in KOH, thin-walled; cap cuticle 140-160 microns thick, epicutis "a narrow layer of interwoven hyphae with free hyphal tips and pileocystidia", (Thiers)
Spore deposit: pale orange-yellow, Crawshay C-D, (Phillips), pale orange-yellow, Romagnesi IIb or slightly lighter (Shaffer)
Habitat / Range
single, scattered, or gregarious on humus in deciduous, coniferous, and mixed woods, (Shaffer)
Russula laurocerasi is slightly smaller, yellower, cleaner, slimmer (in general stem more than 3 times as long as wide), with stronger more fragrant odor, and larger-spored with higher ornamentation, (Shaffer, who notes "Intermediates between these species exist, however."), R. laurocerasi has smaller spores with heavier and more conspicuous ornamentation, and the odor, which is similar to the odor of R. fragrantissima when young, does not become strongly fetid with age and does not persist in the dried specimens, (Thiers); Russula fragrantissima is like R. foetens Fr. sensu Romagnesi but has distinct benzaldehyde odor, which is present at least during the early stages, and spore ornamentation resembles that of R. laurocerasi but is lower, (Shaffer)
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2020-07-11 10:35:44 AM
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