E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) a spherical to lobed whitish fruitbody that becomes pinkish on handling or with exposure to light, 2) a peridium (outer skin) separating easily from the firm, rubbery, greenish spore mass, 3) a well developed branching columella, 4) underground growth, and 5) microscopic characters including wrinkled spores and mostly 2-spored basidia. It is common among false truffles in the Pacific Northwest (Trappe(13)). It is the most common spring truffle in the western US (Trappe, M.(1)).

It is found from OR to southern CA and AZ, (Trappe(13)). The distribution includes New England states, NY, WY, AZ, OR, CA, Chile, Argentina, and Europe, (Zeller(8)). Oregon State University has collections from WA, OR, AK, CA, and NY. The University of British Columbia has collections from BC.

Outer Surface:
0.5-3cm across, spherical to somewhat flattened or lobed, "white to pinkish or sometimes buff, often becoming pinkish where bruised or handled"; peridium tends to crack and peel easily from the greenish spore mass, (Arora), to 3cm across, white slowly becoming pinkish to brown where bruised; peridium readily cracking and separating from spore mass, (Smith), up to 1.5cm across, spherical; white when young becoming "pale ochraceous-buff" or "light ochraceous-salmon" when fresh, becoming "buff-pink" to "onion-skin pink" where bruised, drying "ochraceous tawny" to "mummy-brown"; no fibrils in upper part, but fibrils in lower part variable from terete [round in cross-section] and free to innate or appressed, (Zeller(8)), "white bruising pink to red or rosy brown", separating easily from the spore mass, (Trappe, M.(1))

Stem:
stem absent, "sometimes with mycelial fibres at the base", "columella thin, translucent or whitish, arising from a rudimentary sterile base, often branched" and typically extending about halfway into spore mass, (Arora), columella prominent, often branched, (Smith), columella usually large and prominent, reaching half way to the top of fruitbody "or often branching near the base", (Zeller), columella narrow, dendroid, (Trappe, M.(1))

Interior:
olive-brown to greenish; composed of small chambers, "at first firm and tough (cartilaginous), but becoming slimy and stinky (putrid) at maturity" or when old, (Arora), green to olive green; "cartilaginous becoming mucilaginous at maturity", (Smith), green when fresh, becoming "citrine drab" or "grayish-olive" to "dark greenish-olive" on drying; "cavities polyhedral to irregular, with a tendency to radiate from the columella, small, empty", (Zeller(8)), "dark olive green, very firm and rubbery", (Trappe, M.(1))

Odor:
offensive at maturity (Zeller(8)), "mild to faintly fruity or sometimes of iodine", (Trappe, M.(3))

Taste:
pleasant when young (Zeller(8))

Microscopic:
spores 12-19 x 6-8 microns, more or less spindle-shaped, smooth within a wrinkled sac, colorless to pale greenish brown under microscope, (Arora), spores 12-19 x 6-8 microns, spindle-shaped, (Smith), spores 12-19 x 6-8 microns (averaging 15.3 +/- 0.9 microns long), lanceolate, "with a thick epispore which sometimes is slightly roughened" and becomes loosened when old, sometimes papillate at apex, spores olivaceous in mass; basidia 3-4-spored, mostly 3-spored, long, irregularly cylindric, sterigmata usually short, but sometimes becoming 16-18 microns long; septa 85-140 microns thick, composed of hyphae 5-7 microns wide, loosely interwoven, large, thin-walled, finally becoming highly gelatinized; peridium 220-450 microns thick, parenchymatous, cells spherical to polyhedral, varying from 12 to 40 microns in diameter "with a very thin filamentous layer between the parenchyma and gleba, easily separable", (Zeller(8)), spores 11-14 x 4-5 microns, fusoid, smooth, "enclosed in a wrinkled outer skin", (Trappe, M.(1)), inflated cells in peridium, (Trappe, M.(3))