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.). . 



Fig. 332.— Distribution of P. nodatum. 



ligules 



Seoparia. — Vernal culms tall; blades flat, elongated, not over 1.5 cm. wide 



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. P. viscidellum. 



Pubescence when present not velvety. 



Spikelets elliptic; fruit 2 mm. long 180. P. aculeatum. 



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. P. scabriusculum. 



Sheaths glabrous; autumnal form sparingly branching. 182. P. cryptanthuwi. 



178. Panicum scoparium Lam. 



Panicum scoparium Lam. Encycl. 4: 744. 1798. "Cette plante a £te 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 l'herbier de Vaillant; il 

 l'avoit recue de Sherard en 1721. Le citoyen Michaux l'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. 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 & 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 pauciflorum 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. 



« Fl. Brit. Ind. 7 : 34. 1896. 



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



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



1908. 



