Conidia (spores) of the deuteromycotan fungus, Alternaria alternata (FRIES,1832) KEISSLER,1912. The conidia are obclavate (shaped like a bowling pin) and form single file chains as seen here. The spores have both longitudinal and horizontal septae. Each conidium tapers into a narrow rounded protuberance. Alternaria digests cellulose and is commonly found on dead grasses. Some species are plant pathogens causing "early" potato and tomato blight and leaf rot. The Irish potato famine of 1845-1849 was due to inection by a different fungus, Phytophthora infestans which causes "late" blight.These specimens of A. alternata were found at the margins of a slow-moving freshwater stream in Boise, Idaho.Since A. alternata is terrestrial and not aquatic, the water was probably contaminated by airborne conidia.Phase contrast. This image was taken by William Bourland. He now uses a Zeiss Axioskop 2 with Spot Insight and Spot Flex CCD cameras (Diagnostic Instruments). Image copyright: William Bourland, image used under license to MBL (micro*scope).
download as pdf file
download large file
From the collection
Freshwater and Terrestrial Microbes of Idaho (USA) and Elsewhere
No description of Alternaria alternata available.
Contact site management to have description written.