The imperfect fungi. (a) Verticillium alboatrum (1350×), an important pathogen of alfalfa,
has whorled conidiophores. The single-celled conidia of this member of the imperfect
fungi are borne at the ends of the conidiophores. (b) In Tolypocladium inflatum, the conidia
arise along the branches. This fungus is one of the sources of cyclosporin, a drug that
suppresses immune reactions and thus assists in making human organ grafts possible; the
drug was put on the market in 1979. (c) This scanning electron micrograph of Aspergillus
(a) shows conidia, the spheres at the end of the hyphae.