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

Summary:
Features of the Nemania serpens complex include 1) growth on many kinds of wood, in the form of rounded to oval, coal-like crusts that can coalesce to cover large surfaces, the dark brown to black surface carpeted with dots representing the openings of the perithecia, 2) an absence of pigments released in 10% KOH (presence of these pigments being a general feature of Hypoxylon species), 3) spores that are usually within the range 10-18 x 4-7.5 microns, and brown, with an inconspicuous or conspicuous germ slit, 4) the ascus tip blueing in iodine in some species. Miller, J.H.(1) used the name Hypoxylon serpens in this wide sense that has been considered untenable by more recent investigators: Rogers, J.D.(3) and Ju(4) favor a narrower concept and refer for descriptions to Petrini(1) and to Granmo, A., T. Laessoe & T. Schumacher, The genus Nemania s.l. (Xylariaceae) in Norden. - Sommerfeltia 27: 1-96. 1999.

Collections were examined of Nemania serpens var. serpens from BC, WA, OR, ID, AZ, ME, NC, PA, SC, Chile, Czechoslovakia, Denmark, France, Germany, Sweden, Switzerland, and the United Kingdom, (Petrini). It also occurs in Norway (Ju). Note however that while Ju(4) states that the type of H. atropurpureum var. brevistipitatum in Petrini(1) is Nemania serpens var. colliculosa, Petrini(1) synonymizes Sphaeria colliculosa Schwein. with Hypoxylon serpens, so that it is possible some of the records above for Nemania serpens var. serpens are actually Nemania serpens var. colliculosa. Another variety of Nemania serpens is var. hydnicola (Schwein.) Y.-M. Ju & J.D. Rogers which ''differs from the typical variety in that its ascus rings are amyloid, the ascospores have abruptly narrowed or "pinched" ends, and it is frequently fungicolous on Fomitopsis pinicola'': this variety has been found in BC as well as Norway, Sweden, Finland, and France, (Callan, Latin name italicized).

Fruiting body:
stroma 0.5-7cm x 0.2-3cm, and 0.08-0.1cm thick; dark brown to black, "sometimes covered with greenish mass of spores"; contours of perithecia on the stroma surface not present or only at margin, ostioles finely, seldom coarsely papillate, occasionally in annulate depressions, (Petrini), stromata superficial, orbicular [circular] to elliptic, small or widely effused [spread out], 0.2-4cm x 0.2-2cm and 0.1-0.15cm thick, "varying with irregularities of bark or wood", carbonous; at first white and when old varying to pruinose-gray, "later bronze and finally dark purple or black"; "smooth or very uneven with projecting perithecia and conic papillate ostiola", (Miller), stroma rounded-oval, dark coal-like, 1-2cm long, (can fuse with others to form larger surfaces), black perithecia "irregularly embedded in a single layer" in stroma; stromal surface "blackish, tuberculate and uneven, and carpeted with dots (the projecting perithecial ostioles)"; when young the stroma is light-colored within, (Breitenbach)

Microscopic:
SPORES (10)11.5-14(18) x 4-6.5 microns, light brown, apices broadly rounded, germ slit short, obscure; ASCUS stem (32)60-103(138) microns, ratio of spore-bearing part to stem 0.6-1.5(1.8), ascus tip mostly not blueing in iodine, but sometimes blueing; PERITHECIUM up to 900 microns wide, (Petrini), SPORES 10-14(16) x 4-6 microns, brown, with broadly or less frequently narrowly rounded ends; ASCUS with apical ring not blueing in Melzer''s reagent; PERITHECIUM 400-800 microns, (Ju), SPORES 10-15 x 5-7 microns, "oblong to inequilaterally elliptic with obtuse ends, light to dark brown"; ASCUS 75-100 x 6-9 microns in spore-bearing part, cylindric, long-stemmed, with stem 40-60 microns long; PARAPHYSES filiform, copious; PARATHECIA 500-1000 microns in diameter, spherical to compressed-ovate, (Miller), SPORES 12-13(15) x 5.5-7 microns, oval, sometimes flattened on one side, smooth, brown, with one droplet, without germination cleft, (Breitenbach)