Isoplanogametes in Blastocladia

Abstract

Blastocladia has been considered by some students of the genus as lacking sexual reproduction. On the other hand Butler (1) and Kanouse (3) considered the thick-walled resting spores to be oogones, perhaps parthenogenetic in function. The latter author described an antherid-like structure at the end of a slender filament and considered it to be a true antherid. The writer in October 1935, obtained numerous colonies of Blastocladia Pringsheimii Reinsch by suspending fruits of Rosa and Crataegus in the Red Cedar River and in a pool in the Beal Botanical Garden, both on the campus of Michigan State College. This is the commoner species obtained in this manner but B. globosa Kanouse is also found some autumns. The colonies appeared as grayish tufts on the surface of the fruit, 0.1 to 0.5 mm. in diameter and height. Each such tuft consisted of many plants whose branches were more or less entangled, all embedded in a bacterial slime. When the fruits were washed under a rather