Basidium sentence example
Conidia (basidiospores) borne in fours on a special conidiophore, the basidium.
Life-history in some cases very complex and with well-marked sexual process and alternation of generations, in others much reduced; basidium (promycelium) derived usually from a thick-walled spore (teleutospore).
Life-history always very simple, no wellmarked alternation of generations; basidium borne directly on the mycelium.
This conjugate condition is finally brought to a close by the nuclear fusion in the basidium.
The sporophyte may be considered to begin at the stage of nuclear association and end with the nuclear reduction in the basidium.Advertisement
C, A basidium before the four nucleiderived from the secondary nucleus of the basidium have passed into the four basidiospores.
There is also a further reduction in that the basidium is not derived from a teleutospore but is borne directly on the mycelium.
Formerly, before the relationship of promycelium and basidium were understood, the Uredineae were considered as quite independent of the Basidiomycetes.
This, by far the smaller division of Basidiomycetes, includes those forms which have a septate basidium.
The first named contains a small number of forms with the basidium divided like the promycelium of the Uredineae.Advertisement
P. Petersii has a transversely divided basidium as in Auriculariaceae, but the basidia are surrounded with a peridium-like sheath.
In this by far the larger division of the Basidiomycetes the basidia are undivided and the four basidiospores are borne on short sterigmata nearly always at the apex of the basidium.
In young asci a similar fusion of two nuclei occurs, and also in basidia, in each case the nucleus of the ascus or of the basidium resulting from the fusion subsequently giving rise by division to the nuclei of the ascospores and basidiospores respectively.
This very large group of plants is characterized by the possession of a special type of conidiophore - the basidium, which gives its name to the group. The basidium is a unicellular or multicellular structure from which four basidiospores arise as outgrowths; it starts asa binucleate structure, but soon, like the ascus, becomes uninucleate by the fusion of the two nuclei.
Between the nuclear association and the nuclear fusion in the basidium many thousands of cell generations may be intercalated.Advertisement
The teleutospore puts forth on germination a fourcelled structure, the promycelium or basidium, and this bears later four sporidia or basidiospores, one on each cell.