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1-tO Chase — Notes on Genera of Panicetz. IV. 



Nb. (Paspalum repens Berg.)," are included, the first of which is here 

 taken as the type 



Dimorphostachys Fourn. Compt. Rend. Acad. Sci. Paris. 80:441. 

 1875. This genus is proposed because of the presence of the first glume 

 of the spikelet, this glume in the lower of the pair of spikelets being 

 larger than in the upper. The author says the group contains eleven 

 species, but four of which he mentions, Panicum monostachyum H. B. K. 

 Paspalum pilosum Lam., Paspalum oajacense Steud., and Paspalum 

 pi iliinculatum Poir. Founder does not here actually transfer any species 

 to Dimorpho8tachys. His lirst named species, which we take as the type, 

 was, together with the others given in his posthumous work ( Mex. PI. 

 2 : 14-1(>. 1886*), published under this genus by Hemsley (Biol. Centr. 

 Anier. Bot. 3 : 499. L885), as l>. monostachya Fourn., based on Panicum 

 monostachyum II. B. K. 



The section Harpostachys of Panicum established by Trinius (Mem. 

 Acad. I'etersh. Y I . Sci. Nat. 3 2 : 227. 1834) for species having a simple, 

 solitary raceme, if typified by the first group of species included in it, 

 Panic a nt decumbens Poem. & Schult. (based pn Paspalum decumbens 

 Sw., of which /'. pedunculatum Poir. is a synonym) and Panicum mono- 

 stachyum II. B. K-. is synonymous with Dimorphostachys . In this sec- 

 tion, however, Trinius included a uumber of remote species, the wholly 

 artificial character on which it is based bringing ton-ether, besides the 

 two species of Pas pa I um mentioned above, Thrasya paspaloides H. B. K. 

 and congeners ; Panicum repandum \ees, a^species related to P. obtusum 

 II. P>. K., Echinolaena hirta, and Panicum sclerochloa Trin. and other 

 species referable to Mesosetum. 



Wirtgenia Nees; Doell in Mart. PI. Bras. 2' 2 : 40. 1877. " Wirtgenia pas- 

 paloides Nee- ab Esenb. in herb. Pen'. Berolin.", a herbarium name for 

 the species Nees published as Anachyris paspaloides, is here given as a 

 synonym of Paspalum malacophyllum Trin. 



c \\€-y s< ^ ™T qtu. The relationship of the various species upon which are based the pro- 



phet. ^ i%* < *» posed genera here included as synonyms, of Paspalum together with the 



history of these groups will be discussed in the projected revision of 



North American species of Paspalum. 



Description. — I nllorescence of ] to numerous, simple, spike-like racemes, 

 along a common axis; spikelets plano-convex, usually obtuse, subsessile 

 (rarely on pedicels as long as the spikelets) solitary or in pairs, in two 

 rows on one side of a narrow or dilated rachis, the back of the fertile 

 lemmaturned toward it;t lirst glume typically wanting ( regularly present 

 in a few species, occasionally present in others; in a few species both 

 glumes wanting); second glume and sterile lemma subequal, the glume 

 rarely shorter; fruit usually obtuse, the lemma and palea chartaceous- 

 indurated (rarely but slightly so), the margins of the lemma inrolled. 



•For discussion of date of tin's work s>m> Hitchcock & Chase, Contr. Nat. Herb. 15 : 

 49. 1910. 



-rowing to a tortion of the short pedicels the crowded, paired spikelets are often 

 turned edgewise to the rachis or even entirely reversed, but in all species examined 

 the spikelet is attached with the hack of its fertile lemma toward the rachis. 



