Chase — Notes on Genera of Panicecz. IV 



141 



Mostly perennials, of various habit; a large genus of the tropics and 

 warm temperate regions of both hemispheres, but the species much more 

 numerous in the western hemisphere. 



The characters here considered as of chief generic value are the strictly 

 racemose inflorescence, the plano-convex (sometimes slightly concavo- 

 convex) spikelets in which the first glume is wanting, and the obtuse, 

 indurated fruit, the margins of the lemma inrolled, taken in combination. 

 But in this large, on the whole well-marked genus, there are many species 

 which depart more or less from some one or two of these characters. 



17. Genus PANICUM L. 



Panicum L. Sp. PI. 55. 1753. This genus is discussed by Hitchcock & 

 Chase (Contr. Nat. Herb. 15 : 11-18. 1910) and the type species shown to 

 be Panicum miliaceum L. The generic names included as synonyms 



under Panicum, 

 so far as these are 

 based on North 

 American spe- 

 cies, are there 

 accounted for. 

 The genus in re- 

 lation to the 

 South American 

 and Old World 

 species upon 

 which genera 

 have been pro- 

 posed will be dis- 

 cussed in a later 

 paper. In the 

 above mentioned 

 work, under the 

 genera excluded 



from Panicum (op. cit. 16), is given Panicum tuerclcheimii Hack., "an 

 anomalous species with spikelets in which the first glume is wholly want- 

 ing, and in which no rudiment of a palea is found in the sterile lemma." 

 This statement is found to be partly erroneous. There is present a small 

 hyaline first glume, so transparent as to be invisible in the dry spikelet, 

 which escaped the notice of Hackel and of ourselves. This species, though 

 unique, we now include in the genus Panicum. It will be described and 

 the spikelet figured in a forthcoming paper (by Hitchcock & Chase) on 

 the Mexican and Central American species of Panicum, a supplement to 

 the recent revision of the genus. 



Chasea Nieuwl. Amer. Midi. Nat. 2 : 63, 64. 1911. This name is pro- 

 posed as " nov. nom. Panicum of the authors not of Linnaeus or only 



Fig. 9. 



Panicum miliaceum. 



(Two views of spikelet and fruit x 10 diam.) 



