Search on : Taxa descriptions


Remarks (public):For a complete description including images see 
Remarks (internal):Spore germination is by a two-celled aerial promycelium. This is an important character for separation from Cintractia Cornu, a morphologically similar genus that also parasitizes Cyperaceae; another distinction is the formation of Cintractia spores in sporogenous pockets interspersed between bands of fungal stroma. It has been suggested (Ingold, 1989) that because of its unusual germination, Anthracoidea could be segregated from Ustilaginaceae (in which it has traditionally been included) and placed in a separate family. Anthracoidea caricis is the type species of its genus. Since its first description it has been interpreted in two different ways. In the narrow sense, it is one of a group of `small' species evolved with their Carex hosts and each confined to a limited number of Carex species or sections. In the broad sense all these `small' species are united under A. caricis, with a wider host range and geographical distribution than suggested here. The host-parasite combinations are not economically significant and there has been very little experimental work not directly related to taxonomy. The species or species-complex is, however, interesting in biodiversity studies. Additional species of Anthracoidea regularly found on Carex section Acrocystis are: A. caryophylleae on C. caryophyllea, A. globularis on C. globularis and A. tomentosae on C. tomentosa; these differ in fine details of ustilospore size, shape, wall thickening and ornamentation and, for A. tomentosae, pattern of germination. Other smut genera represented on Carex: Farysia (small spores, initially in chains), Orphanomyces, Schizonella (sori in leaves, spores single or in pairs respectively), Tolyposporium, Urocystis (spores in balls) are unlikely to be confused with Anthracoidea. Planetella lironis is similar to Anthracoidea in all respects except that its spores have a dark equatorial band and light polar areas; it is found on section Vignea in North America.
Description type:Non-original description 
Description:Anthracoidea caricis (Pers.) Bref., Unters. Mycol. 12: 144, 1895.
Uredo caricis Pers., Syn. meth. Fung.: 225, 1801.
Ustilago caricis (Pers.) Unger, Einfl. Boden. Verth. Gew.: 211, 1836.
Cintractia caricis (Pers.) P. Magnus, Verh. bot. Ver. Prov. Brandenb. 37: 78, 1896; '1895'.
Sori in the spikelets replacing the ovaries, partly hidden by the glumes, usually globose, about 2-3 mm diam., less often ovoid to elongated. Sorus covering a thin white to grey false membrane of fungal cells, hyphae and fragments of host cells which disintegrates, exposing the spore mass, as the sori attain their full size. Spore mass black, homogeneous, firmly agglutinated, eventually becoming granular to moderately powdery as it weathers away to expose a central columella of host tissue. Columella simple, unbranched, composed of vascular tissue and parenchyma, surrounded when young by a continuous layer of sporogenous mycelium. Ustilospores round, oval or commonly polygonal in face view, discoid in side view, sometimes with fragments of semi-gelatinized hyphae attached, dark brown, frequently almost opaque, 17-28 x 14-22 (mean 21,4 x 17,6) µm in face view, the discs 11-16 (mean 13,2) µm thick. Ustilospore wall unevenly 1-4 µm thick, thickest in the angles of polygonal spores and usually with 1-3 inconspicuous internal swellings elsewhere, occasionally with small light-refractive areas; wall ornamentation minutely verruculose, the warts low, rounded, densely and evenly arranged.
Hosts: Carex pilulifera, Carex montana and occasionally other species of Carex in section Montanae. In addition to these, its regular principal and accessory hosts, a few A. caricis sori occur rarely on other, probably unrelated, species of Carex.
Disease: Smut of Carex. Since the ovaries are destroyed, infected flowers cannot set seed. However, infection is not systemic but is confined to individual florets, often leaving parts of the inflorescence to develop normally; seed production is therefore reduced, not prevented entirely.
Geographical distribution: Europe: Austria, Czechoslovakia, Denmark, Estonia, Finland, France, Germany, Greece (52, 2856), Hungary, Iceland, Norway, Poland, Romania, Russia (European region), Sweden, Switzerland, UK (Scotland); North America: Canada (Alta, BC, Man., NS, NT, Ont., Que., Sask.); Greenland; USA (AK, CO, CT, DE, IA, IL, IN, MA, ME, MN, MT, ND, NH, NY, PA, RI, WI, WY) (Kukkonen, 1963; 69, 2765).
Physiological specialization: Not known.
Transmission: Ustilospores and basidiospores are disseminated by wind and rain, possibly also by insects living in the sedge tussocks. Infection occurs in individual inflorescences. It is thought that high latitude and altitude favour infection because a comparatively short vegetation period increases the chances of synchronous anthesis and ustilospore germination and therefore of successful infection. High atmospheric humidity also may be important for infection (Nannfeldt, 1979).
Literature: Kukkonen, Annales Botaniki Societatis Zoologicae Fennicae 'Vanamo' 34: 1-122, 1963; Nannfeldt, Symbolae Botanicae Upsalienses 22: 1-41, 1979; Ingold, Mycological Research 92: 245-246, 1989; Vánky, European Smut Fungi, Stuttgart, Gustav Fischer Verlag, 1994.

Taxon name: