Mycologia 37(6): 666. 1945.
Common Name: none
Synonyms: Myriosclerotinia sulcata (Roberge ex Desm.) N.F. Buchw.; Sclerotium sulcatum Roberge ex Desm.
Fruiting body stipitate-cupulate, the cup 9-15 mm broad, 8-15 mm deep, exterior surface slightly undulate, dingy brown, finely pubescent; margin slightly incurved at first, then erect; hymenium dingy brown, glabrous, hygrophanous, drying unevenly to lighter shades; stipe slender 1.5-3.0 x 25-45 mm tall, cylindrical, hollow, more or less equal to enlarged towards the cup; surface sparsely pubescent, dingy buff at first becoming dark brown below, arising from a blackish sclerotium; odor and taste not noted.
Spores 10-15.5 x 5-7.5 µm, ovoid, hyaline; asci cylindrical, apex amyloid with Meltzer’s reagent, eight spored, spores uniseriate.
Scattered to gregarious in wet meadows in the Sierra Nevada and likely in Coast Ranges; fruiting in the spring from blackish sclerotia developing on culms of sedges (Carex spp.); uncommon.
Sclerotinia sulcata is a stipitate cup fungus with an unusual fruiting habit. It typically fruits in standing water of montane marshes in the spring. Its rarity, drab color, and the likelihood of wet feet, all make this Ascomycete a challenging find. It is recognized by a brownish cup set on slender brown stipe attached to a typically submerged blackish sclerotium. Unfortunately, these features are shared to some extent with a more common Sclerotinia, S. veratri, also found in marshes, but is smaller, paler in color, and has shallower cups. Characteristic of the genus Sclerotinia, both species are plant pathogens, but on different plants, Sclerotinia sulcata on the culms of sedges (Carex spp.), S. veratri on the stems of corn lilly (Veratrum californicum). Fruiting bodies of the two species develop in the spring from over-wintering blackish sclerotia. Besides Sclerotinia sulcata and S. veratri, one can find numerous small Ascomycetes fruiting in boggy areas. Two that are common and relatively easy to identify are Cudoniella clavus, a tiny buff to greyish stipitate disc on rotting marsh plants, and Mitrula elegans, the “match stick fungus”, named for its yellowish fertile head and pallid stipe that resembles a match.
Beug, M.W., Bessette, A.E. & Bessette, A.R. (2014). Ascomycete Fungi of North America. University of Texas Press: Austin, TX. 488 p.
Breitenbach, J. & Kränzlin, F. (1984). Fungi of Switzerland. Volume 1: Ascomycetes. Verlag Mykologia: Luzern, Switzerland. 310 p.
Dennis, R.W.G. (1981). British Ascomycetes. J. Cramer: Vaduz, Liechtenstein. 585 p.
Hansen, L. & Knudsen, H. (2000). Nordic Macromycetes. Volume 1. Ascomycetes. Nordsvamp: Copenhagen, Denmark. 209 p.
Kohn, L.M. (1979). A monographic revision of the genus Sclerotinia. Mycotaxon 9(2): 365-444.
Seaver, F.J. (1951). The North American Cup-Fungi (Inoperculates). Privately Published: New York, NY. 428 p.
Whetzel, H.H. (1945). A Synopsis of the Genera and Species of the Sclerotiniaceae, a Family of Stromatic Inoperculate Discomycetes. Mycologia 37(6): 648-714.