THRAUSTOTHECA CLAVATA 



W. C. COKER AND O. W. HyMAN 



(With Plate 63, Containing 10 Figures) 



During the course of our study of the Saprolegniaceae we 

 brought into the laboratory early in January, 191 1, a number of 

 collections from promising pools and runs. Several different 

 species developed in a couple of days. One of these taken from 

 an open ditch in the arboretum was at once conspicuous on ac- 

 count of its stout hyphae and irregular branches. This soon de- 

 veloped club-shaped sporangia and by its method of spore libera- 

 tion was at once recognized as the rare and interesting species 

 Thraustotheca clavata (De Bary) Humphrey. 



This mold seems not to have been found since its first discov- 

 ery in 1880. In 1888 De Bary described it as a new species under 

 the name of Dictyuchus clavatus} He got his specimens from a 

 collection of algal material taken in 1880 by Stahl from a fresh- 

 water lake at Vendenheim near Strassburg, Germany, and kept it 

 growing in his laboratory for four years. The species was really 

 first published incidentally by Biisgen in 1882,^ who in his study 

 of the development of the sporangia described it sufficiently under 

 the name of Dictyuchus clavatus De Bary sp. nov. 



On account of the unparalleled method of spore liberation it 

 was suggested by Solms-Laubach, who, after De Bary's death, 

 arranged and edited his last paper, that this species might be con- 

 sidered as generically distinct from the other species of Dictyu- 

 chus. This was again remarked on by Fisher in 1892,^ and the 

 next year, Humphrey in his Saprolegniaceae of the United States 

 was sufficiently impressed with its distinction to give it the 

 generic name of Thraustotheca. 



A pure culture of our Chapel Hill plant was obtained as fol- 



^ Bot. Zeitung 46 : 649. i88'8. 



^ Pringsbeim's Jahrb. f. wiss. Botanik, 13: 253. 1882. 

 ^ Rabenhorst's Kryptagamen Flora i: 365. 1892. 



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