1912} Hubbard,— Nomenclatorial Changes in Gramineae 185 
TRIDENS R. & S. 
The genus Tridens of Roemer and Schultes [Syst. Veg. 2 : 34, 599 
(1817)] in its commonly accepted sense is antedated by Tricuspis 
Beauv. Agrost. 77, t. 15, fig. 10 (1812). The generic description of 
Tricuspis is fairly good and its identity is unquestionable. It is com- 
monly cited as a synonym of Tridens [in fact it is given as a synonym 
by Roemer and Schultes l. c. 34] when that genus is separated from 
Triodia R. Br. According to the American Code Tricuspis Beauv. is 
untenable on account of the older Tricuspis Pers. Syn. 2 : 9 (1807), 
but by Sect. 7, Art. 50 of the “Vienna Code" Tricuspis Pers. which 
equals Crinodendron Molina, Saggio Chile 179 (1782) [a genus of 
Elaeocarpaceae] does not invalidate Tricuspis Beauv. 
Beauvois after describing his genus cites Poa coerulescens Mich. 
[should be Michx.] and gives his combination Tricuspis Novaeboro- 
censis Nob. without description. According to Ind. Kew. 2 pt. 1, 
571 (1895) Poa coerulescens Michx. ex Kunth is described in Kunth 
Enum. Pl. 1:319 (1833) in syn., but it also occurs in synonymy in 
Kunth Rev. Gram. 1:108 (1829); in both cases under Uralepis 
cuprea Kunth. In Rev. Gram. there is a plate (t. 68) which agrees 
very fairly with Beauvois' illustration. 
Kunth in Enum. Pl. 1:319 (1833) among other synonyms of his 
Uralepis cuprea cites Poa coerulescens Michx. [upon which Beauvois 
bases his genus Tricuspis]; P. seslerioides Michx. Fl. Bor. Am. 1 : 68 
(1803); P. quinquefida Pursh Fl. 1:81 (1814); Triodea cuprea Jacq. 
Eclog. Gram. 2 : 21, t. 16 (1814) and Tricupis noveboracensis Beauv. 
Agrost. 77 (1812) with a question mark. 
Triodia cuprea Jacq. is the name used for the first species of T'riodia 
by Watson & Coulter in Gray Man. ed. 6, 657 (1890) while in the 
first edition we find Prof. Gray using Tricuspis seslerioides Torr. with 
the following synonyms: Poa flava L., P. seslerioides Michx., P. quin- 
quefida Pursh and Windsoria poaeformis Nutt.  Tricuspis seslerioides 
is given as a synonym of T'riodia cuprea Jacq. in edition six and this 
in turn is shown to be a synonym of Tridens flavus (L.) Hitchc. 
Ruopora 8:210 (1906). This is the first species under Tridens in 
Gray Man. ed. 7, 149 (1908). 
This chain of equivalents shows conclusively that the type species 
of Tricuspis Beauv. is unquestionably the same as Tridens flavus (L.) 
Hitche. and consequently the older Tricuspis Beauv. (1812) replaces 
Tridens R. & S. (1817). 
