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

Summary:
Features include an annual, dark brown to almost black, semicircular cap that appears velvety at first and is often zoned and wrinkled, at first exuding resin, and a white pore surface when fresh that turns dark quickly when touched. The rotted wood has an anise odor. The description is derived from Gilbertson(1) except where noted. Some authors (Breitenbach(2), Lincoff(2), but not Gilbertson(1)) separate Ischnoderma benzoinum growing on conifers and with darker flesh and tubes from Ischnoderma resinosum growing on hardwoods.

Ischnoderma resinosum has been found in BC, WA, OR, ID, MB, ON, PQ, AK, AR, AZ, CA, CO, CT, DE, FL, IA, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, MT, NC, NE, NJ, NY, OH, PA, RI, TN, VA, VT, WI, and WV, and it is circumglobal through Northern Asia to West Europe, (Gilbertson).

Cap:
up to 12cm broad, 15cm long, and up to 3cm thick at base, usually semicircular with tapering base or broadly attached, upper surface "first finely tomentose and dark brown, when fresh more or less even, later the tomentum disappears in concentric zones, exposing a slightly glossy black resinous crust, shrinking when dried and with numerous radial furrows and some broad sulcate bands, margin even or lobed to incised", (Gilbertson), 7.5-25cm long, semicircular, with thick rounded margin, exuding water drops when young; ocher to dark brown, becoming blackish; "velvety, hairy, becoming smooth at maturity, sometimes concentrically furrowed; often with dark shiny, crusty, resinous zones, often radially wrinkled", (Lincoff), resinous areas often darker and more metallic-looking and sometimes slightly bluish; margin usually quite thick, (Arora)

Flesh:
at first fleshy, soft, whitish, later hard, brittle, ochraceous to light cinnamon; separated from the tomentum on the upper surface by a distinct thin black zone that becomes a crust

Pores:
4-6 per mm, angular to round, at first whitish and darker where touched, later pale brown, tubes up to 1cm deep, colored as pore surface

Stem:
with a tapering base or broadly attached, (Gilbertson), "no stem, broadly attached, or with a small stemlike attachment", (Phillips)

Chemical Reactions:
flesh darker with KOH (Lincoff)

Odor:
the rot has a strong anise odor, (Gilbertson), aromatic when fresh, exposed wood sometimes with anise odor, (Trudell)

Microscopic:
spores 5-7 x 1.5-2 microns, cylindric, inamyloid, colorless, thin-walled, illustrated as smooth; basidia 4-spored, 12-18 x 4.5-6 microns, clavate, with basal clamp; hyphal system dimitic: generative hyphae in cap tomentum 4-10 microns, brownish, tortuous, very thick-walled, moderately branched, with a few large scattered clamp connections, in the context dominated by the same type but colorless, more frequently clamped, and in parts swollen up to 12 microns wide (in KOH), in subhymenium 3-5 microns wide, straighter and with slightly thickened walls, skeletal hyphae "partly mixed with the generative hyphae in the context, straight or slightly flexuous, very thick-walled and without sidebranches, 3-10 microns in diameter, whether they are long segments of sclerified generative hyphae or not is difficult to decide, as few clamps were observed in these hyphae, distinctive skeletal hyphae observed only in the trama, straight, thick-walled to solid and light yellowish at maturity, 3-10 microns in diameter"

Spore Deposit:
white (Phillips, Arora)