Search on : Taxa descriptions

 


   
Literature:
 
Remarks (internal):Brachysporium obovatum is the lectotype species of Brachysporium Sacc. (Mason, Mycol. Papers, 2: 9. 1928; and Hughes, Naturalist, Lond., 1951: p. 45. 1951), a choice which has received general acceptance. This species is common in Europe on decaying wood, predominantly of broad-leaved trees (Hughes, loc. cit., 1951; Ellis, Mycol. Papers, 106: 43-54. 1966; Holubová-Jechová, Folia Geobot., Phytotax., Praha, 7: 217-224. 1972). Ellis (Dematiaceous Hyphomycetes. Kew. 1971) listed nine species of this genus, and Holubová-Jechová (op. cit.) added two new species from Czechoslovakia, including B. abietinum (Fungi Canadenses No. 107).-
This species also occurs in the United States: e.g. New York State, Michigan Hollow, IX.1952, DAOM 29155, and Stoddard Brook Road, Alleghany State Park, VI.1961, DAOM 82861 (S.J.H.).

 
Description type:Non-original description 
Description:Brachysporium obovatum (Berk.) Saccardo, Syll. Fung. 4: 427. 1886.
= Helminthosporium obovatum Berkeley, Ann. Mag. Nat. Hist. I, 6: 434. 1841.
Colonies black and effuse. Mycelium immersed, composed of branched septate, pale brown to brown hyphae, 2-4 µm wide. Conidiophores erect, usually arising singly or in small groups, simple, straight or slightly flexuous, septate, dark brown, paler towards apex, up to 430 µm long, 7-8.5 µm wide just above the basal swelling (10-12 µm.), tapering subulately to 3.5-5 µm toward the apex which is often irregular with the remains of conidium pedicels. Conidia develop blastically on successive new growing points at the apex of the conidiophores and are attached by a narrow, cylindrical, usually bent or twisted, hyaline to subhyaline pedicel which is up to 5 µm long and ca. 1.5 µm wide; they occur in a dry cluster at the apex of the conidiophore, and secede readily. Conidia are obovoid to pyriform, smooth, predominantly 2-septate, composed of a small obtruncate subhyaline basal cell, a larger pale brown central cell and a still larger pale brown to brown terminal cell: they measure (18-)20-24(-29) x 10-12.5(-l4) µm wide, and, when detached, carry away with them part of the narrow pedicel, the corresponding part of which persists on the conidiophore.
Substrate: decaying wood or bark of Betula alleghaniensis, Populus and unidentified broad-leaved trees.
Distribution: Quebec, Ontario
 
Taxon name: