What You Should Know
Lentinus arcularius (syn. Polyporus arcularius) is an inedible species of fungus in the genus Polyporus. One of the first mushrooms to appear in the spring. Compare to L. brumalis which has a darker cap without a fringed margin and smaller pores. Interestingly, although DNA evidence places the genus Lentinus among the polypores, other members of the genus have gills, not pores. Gills arose independently in different fungal lineages.
It is fairly small, and has a central stem, along with whitish, angular pores. The most distinctive feature of Polyporus brumalis, however, is its delicately fringed, finely hairy ("ciliate," in Mycologese) cap margin. The cap color ranges from very dark brown to pale tan.
Other names: Fringed polypore, Spring polypore.
Lentinus arcularius Mushroom Identification
Saprobic on the deadwood of hardwoods--especially oaks; causing a white rot; growing alone, scattered, or gregariously; occasionally arising from buried wood and appearing terrestrial; appearing in spring in eastern North America, and summer and fall in the Rocky Mountains and the Southwest.
1–4 cm; convex to flat or shallowly depressed; dry; finely, concentrically scaly with brown to golden brown scales and fibrils over a dull tan ground; the margin adorned with tiny projecting hairs.
Running down the stem; whitish at first, becoming brownish; pores 0.5–2 mm across, hexagonal or angular, radially arranged.
Central or slightly off-center; 2–4 cm long; 2–4 mm wide; equal; dry; brown to yellowish-brown; scaly to hairy; tough; basal mycelium whitish.
White; thin; tough; unchanging when sliced.
Odor and Taste
Odor slightly fragrant, or not distinctive.
KOH negative on all surfaces.
Spores 5–8.5 x 1.5–2.5 µm; cylindrical; smooth; hyaline in KOH. Basidia 27–35 µm long; 2-4-sterigmate. Hymenial cystidia absent. Pileipellis a radial cutis of brown, clamped, somewhat agglutinated elements 4–7 µm wide. Hyphal system dimitic.
Lentinus arcularius Bioactive Compounds
Lentinus arcularius has been chemically investigated (Fleck et al., 1996) yielding isodrimenediol, drimenediol, and related sesquiterpenes. Later, two additional compounds, named isocryptoporic acids H (3-carboxy-2- (2,5,5,8a-tetramethyl- 1,4,4a,5,6,7,8,8a-octahydro-naphthalen-1-ylmethoxy) -pentanedioic acid) and isocryptoporic acid I (3-carboxy-2- (6-hydroxy-2,5,5,8a-tetramethyl-1,4,4a,5,6,7,8,8a- octahydro-naphthalen-1-ylmethoxy) -pentanedioic acid.), were isolated. These isocryptoporic acids are isomers of the cryptoporic acids with drimenol instead of albicanol as the terpenoid fragment (Cabrera et al., 2002).
Lentinus arcularius Medicinal Properties
Both the aqueous and organic fractions from an extract of the mycelial culture of P. arcularius showed antibacterial activity against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus subtilis (Yamac and Bilgili, 2006). Another group had previously reported antimicrobial activity in this species, but also noted some intra-specific genetic differences (Suay et al., 2004).
Polysaccharides extracted from the mycelial culture of P. arcularius and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 90% and 100%, respectively (Ohtsuka et al., 1973).
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