Prototrichia metallica (Berk.) Massee, 1889

Moreno, G., Castillo, A. & Thüs, H., 2022, Critical revision of Trichiales (Myxomycetes) at the Natural History Museum London (BM), Phytotaxa 567 (1), pp. 1-20 : 8

Prototrichia metallica (Berk.) Massee (Figs 7, 8)

Box B.M. 3174 [ BM001247522 ]: sporocarps sessile, globose, brown in color. Peridium thin, translucent, iridescent and light yellow. Capillitium abundant, yellowish-brown, with branched filaments of 4–7 µm diam., ornamented with 2–3 prominent smooth spirals bands, and 3–6 free ends with characteristic filiform extensions (penicillate), sometimes twisted or slightly spirally of 20–50 µm in length. Under the SEM the capillitium shows the smooth, tight spirals and characteristic filiform free ends. Spores are brownish in mass, globose, (12‒)9.5‒11.9(‒12) × (12‒)9.5‒11.9(‒12) µm, av. 10.7 × 10.7 µm, Qav = 1 (n = 25), yellowish by transmitted light, warty to spiny. Under the SEM, the spore ornamentation is of baculate type, formed by baculae of irregular distribution that sometimes join to form short ridges.

Box B.M. 1542 [BM001247523]: very abundant material, with sessile grouped sporocarps. Sporotheca globose, brownish. The macro- and microscopic characters are similar to sample B.M. 3174, but the elaters of the capillitium are somewhat wider (5–8 µm diam.) and the pointed penicillate free ends are more twisted. Spores pale yellowish in LM, globose, 9.7‒13.2(‒14) × 9.7‒13.2(‒14) µm, av. 11.4 × 11.4 µm, Qav = 1 (n = 25), spiny to warty. Under SEM, the spore ornamentation is similar to the one in sample B.M. 3174, except for the smaller and less dense baculae.