294 



CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



This species differs from P. pedicellatum in its stiffer, short-jointed culms, shorter, 

 puberulent, prominently ciliate blades, 

 and pyriform spikelets with a shorter 

 first glume. 



DISTRIBUTION. 



Oak woods in sand dunes, southern 

 Texas and northern Mexico; appar- 

 ently rare. 



Texas: Sarita, Hitchcock 3865. 

 Mexico : Matamoros, Berlandier 

 988, 2418 (last two in Gray 

 Herb . ) . -pj^ 332.— Distribution of P. nodatum. 



S«oparia. — Vernal culms tall; blades flat, elongated, not over 1.5 cm. wide; ligules 



short; spikelets pointed, 7 to 9-nerved. 

 Pubescence soft- villous or velvety; spikelets abruptly pointed. 

 Vernal culms erect or ascending; plants velvety through- 

 out; spikelets about 2.5 mm. long 178. P. scoparium. 



Vernal culms decumbent at base; the upper sheaths more 



or less glabrate; spikelets less than 2 mm. long 179. 



Pubescence when present not velvety. 



Spikelets elliptic ; fruit 2 mm. long 180. 



Spikelets ovate; that is, broadest below the middle; fruit 

 2 mm. long or less. 

 Sheaths or some of them hispid, rarely glabrous; au- 

 tumnal form with crowded branchlets 181. 



Sheaths glabrous ; autumnal form sparingly branching . 182. 



P. visddellum. 



P. aculeatum. 



scahriusculum. 

 cryptanthum. 



xy 178. Panicum scopaiium Lam. 



Panicum scoparium Lam. Encycl. 4: 744. 1798. "Cette plante a ete recueillie dans 

 la basse Caroline par le citoyen Michaux." The type specimen, in the Lamarck 

 Herbarium, is a part of a vernal culm with a single leaf and over-mature panicle. The 

 accompanying label reads, "Panicum scoparium Lam. diet, donne par le C. Michaux." 



Panicum pubescens Lam. Encycl. 4 : 748. 1798. The author refers to two specimens 

 as follows: "J'ai vu de cette espece un individu nain dans I'herbier de Vaillant; 11 

 I'avoit refue de Sherard en 1721. Le citoyen Michaux I'a trouvee dans la Basse- 

 Caroline." The first mentioned specimen is in the Paris Herbarium. It is some 

 species of Brachiaria allied to Panicum villosum Lam. as described by Hooker. o The 

 other specimen referred to is in the Michaux Herbarium and consists of two freely 

 branching autumnal culms of P. scoparium. The accompanying label reads "Pani- 

 cum pubescens Lam. Hab. in pratis sylvestribus Carolinae." Since Lamarck's 

 description applies to the Michaux b rather than to the Sherard specimen we may 

 consider the Michaux plant the type. 



Panicum viscidwm Ell. Bot. S. C. & Ga. 1: 123. pi. 7./. S.c 1816. No specimen nor 

 definite locality is cited. The type in the Elliott Herbarium is labeled: "Panicum 

 viscidum mihi. Hab: in humidis." It consists of a single culm lacking the base, 

 bearing several short branches and an over-mature primary panicle. 



Panicum paucifiorum Bosc; Spreng. Syst. Veg. 1: 313. 1825. This, together with 

 P. scoparium Michx., is placed as a synonym under P. pubescens Lam. We have seen 

 no authentic specimen. 



aFl. Brit. Ind. 7: 34. 1896. 



& See Hitchcock, Contr. Nat. Herb. 12 : 147. 1908. 



c Plates 7 to 10 were issued with vol. 2. 1824. 



