Jackson: North American Ustilaginales 155 



namely, Thecaphora Thornberi Griffiths. 8 The specimen on Ire- 

 sine, while agreeing in general with the description of that spe- 

 cies, seemed to differ in important characters. A definite decision 

 with reference to the relation of the two forms was therefore 

 reserved till the type of T. Thornberi could be examined. Through 

 the kindness of Dr. Griffiths two collection of his species, one of 

 which was the type, were furnished for study. 



The Iresine smut is evidently very closely related to T. Thorn- 

 beri but differs in several important' respects. The sori, while 

 involving the ovaries, are not usually confined to them, as de- 

 scribed for T. Thornberi, but are indefinite, involving the ovaries 

 and the perianth of single flowers or groups of flowers and also 

 occasionally the rachis. The spore balls are much smaller in the 

 species under discussion, measuring 40-75 ^ in globoid balls, 

 reaching 90 fi in occasional ellipsoid balls, while in T. Thornberi 

 the globoid balls are 80-115 /x, in diameter, reaching 145 /x in the 

 ellipsoid ones. The spores are somewhat larger and the mark- 

 ings more prominent than in T. Tornberi. 



The followng description was drawn up as a result of this 

 study : 



Sori localized in the inflorescence, involving the ovaries and 

 perianth of one or a group of flowers, often involving the rachis, 

 forming irregular galls 0.3-3.5 cm - l° n §'» enclosed by a firm 

 grayish-green membrane, which ruptures irregularly, exposing 

 the reddish-brown spore mass ; spore balls solid, subsphaeroid, 

 40-75 fx, or ellipsoid, 50-70 by 60-90 /x, light chestnut-brown, com- 

 posed of many, 15-70, spores; spores variable in shape, irregu- 

 larly polyhedral, prismatic or oblong, 12-20 by 25-32^; inner 

 wall thin, 1-1.5./*, colorless or pale cinnamon-brown, smooth; ex- 

 posed wall 2-4 ix, thick, darker in color with prominent verrucose- 

 rugose markings. 



After this study was finished, but before the present paper was 

 completed, the species was described as Tolyposporium Iresine 

 from the same collection (Deam, 26651) by Dr. J. A. Elliott 

 (1. c). The species, however, obviously belongs to Thecaphora 

 rather than Tolyposporium and this transfer is therefore made 

 above. The author evidently failed to take into account the 



8 Bull. Torrey Club 31 : 88. 1904. 



