BOTANICAL GAZETTE. 271 



tributed to the Smithsonian Institution a manuscript on " The 

 Plants of Louisiana." In this contribution he was aided by Prof. 

 W. M. Carpenter and by Dr. Josiah Hale, who contributed the 

 Cypreacece and Graminece. The Smithsonian did not publish 

 the contribution, and Riddell made an abridgement of it under 

 the title of "Catalogus Florae Ludovicianse" for the New Orleans 

 Medical and Surgical Journal, which published it in 1852. The 

 manuscript catalogue contained descriptions of new species by 

 Prof. Carpenter, and twenty-one species and several varieties by 

 Riddell. The manuscript or the subsequently printed catalogue 

 seem not to have been consulted by Dr. Chapman in his South 

 ern Flora, although Dicliptera Halei, one of Riddell's new 

 species, is inserted. 



While residing in New Orleans, Dr. Riddell was for some 

 years connected with the government mint. He published in 

 1845 a " Monograph of the Dollar," a work containing fac simile 

 impressions of between five and six hundred kinds of United 

 States and Mexican dollars, both genuine and counterfeit. Dur- 

 ing the latter part of his life he did much work with the com- 

 pound microscope, investigating extensively the lower forms of 

 life, and inventing the binocular microscope. As early as 1836 

 he published in Cincinnati a paper on " Miasm and Contagion," 

 in which he advocated that contagious diseases are caused by 

 " organized and living corpuscles of various kinds." This con- 

 tribution became popular, and was republished in Boston. He 

 also contributed considerably to the scientific journals on matters 

 relating to chemistry and other topics. 



Dr. Riddell is said to have been a universal favorite with 

 all who knew him. His students regarded him with adoration. 

 He was a clear, concise lecturer, and a logical thinker. His bus- 

 iness abilities were extraordinarily good, and he amassed a hand- 

 some property. His name is indelibly associated with botany 

 through the genus Riddellia, a name which Nuttall gave to a 

 western Composite. The original species, R. tagetina, has been 

 supplemented more recently by R. Cooperi and R. arachnoidea, 

 both added by Dr. Gray. — L. H. Bailey, Jr. 



Notes on Some Ustilaginese of the United States. 



The study of the Ustilaginece is bfset with difficulties, for not 

 only do the species themselves present comparatively few salient 

 points of distinction, but the generic characters as estimated by 

 recent writers depend largely upon the mode of germination oi 



