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

Summary:
{See also Earthstars Table.} The conspicuous field characters are the "sulcate conic peristome, which is not sharply delimited from the spore sac; the sulcate underside of the spore sac, where it joins the relatively long pedicel, and the well-developed mycelial layer" (Smith(49)). Other characters include spores with large warts.

There is a collection from BC at Pacific Forestry Center (DAVFP) determined by Paul Kroeger, and another collection from BC at the University of British Columbia collected and determined by T. Goward. Geastrum pectinatum is widely distributed - and has been reported from MI (Smith(49)), AB (Schalkwijk-Barendsen(1)), ON, NC, NY, OH, SC, (Coker(3)), FL, PA, (Lloyd via Coker(3)), United Kingdom, (Pegler), and HI, Costa Rica, Mexico, Brazil, Belgium, Germany, Ireland, Netherlands, Norway, Sweden, Israel, China, Japan, Turkey, Congo, South Africa, Australia, and New Zealand, (various sources).

Outer Surface:
2.9-7.5cm across when expanded, exoperidium splitting about halfway into 6-9 non-hygroscopic rays, arched, "rays spreading horizontally or somewhat recurved"; outermost mycelial layer of rays "usually persistent, strongly encrusting soil and debris"; fibrous middle layer of rays whitish or pale yellowish brown, denuded when old, innermost pseudoparenchymatous layer of rays "fleshy when fresh, sheathing the stalk, whitish at first, becoming brown, dark brown when old, often splitting and partly peeling, usually shrinking around the stalk when dry to leave a thickened ring-like zone", (Pegler), 1-2cm across when unopened, outlines obscured by debris because of well-developed mycelial layer; opening and splitting into 8-10 rays in the Michigan collection, "fibrous layer recurving until inner surface is more or less convex and outer surface reversed so as to line the concave part, sinuses of rays extending about half way to point of attachment of spore sac; fleshy layer (covering convex surface) near wood brown to cinnamon brown and in drying cracking into very irregular patterns and, according to most authors, flaking off at maturity, much debris held in place in the concave part of expanded fructification", (Smith(49))

Inner layer:
1.5-2.7cm in diameter, more or less spherical or depressed, "frequently ridged or striate on the underside and tapered towards the stalk"; "with a pale brown, mealy covering when fresh", when abraded becoming gray-brown to dark brown or lead-gray, with a whitish pruina, otherwise smooth; peristome [mouth] 0.2-0.5cm high, conic, usually strongly plicate [pleated], with 20-32 ridges, "clearly delimited but not bounded by a circular ridge", (Pegler), spore sac 1-2cm across, nearly spherical to urn-shaped, "purplish drab beneath a hoary sheen", "part which narrows to pedicel often radially sulcate, smooth in some, according to most authors"; "mouth conic, sulcate-striate, at base not sharply separated from spore-sac membrane" (Smith(49))

Spore Mass:
dark brown when mature; columella usually narrowly conic and protruding more than halfway into the spore mass, whitish or pale brown, (Pegler), chocolate brown (Smith(49))

Stem:
stalk 0.3-0.5cm high, cylindric or compressed, whitish or gray-brown when denuded, (Pegler), stalk up to 0.6cm long "and often with collar or ring near the middle or base", (Smith(49))

Microscopic:
spores 4.2-4.8 microns excluding ornamentation, 6-7 microns including ornamentation, round, coarsely verruculose, warts cylindric or club-shaped, blunt, 0.6-1.2 microns high, 0.4-1.5 microns across, sometimes coalescent, spores dark yellow brown; basidia not seen; capillitial hyphae 3-7 microns wide, "dark yellow-brown to brown, tapered, simple or occasionally forked near the tips, thick-walled with a narrow lumen, smooth or slightly encrusted", (Pegler), spores 4.5-6 microns in diameter, round, bister (dull dark brown), covered with flat-topped colorless warts; capillitial threads 4-7 microns wide, "in KOH the walls sordid yellowish to brownish, in iodine paler and brighter yellow, very evenly tapered to apices, unbranched to sparsely branched", (Smith(49))