230 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Gymnothrix distachya Fourn. Mox. PI. 2: 48. 188G. "Pennisetum ditiachyvm Rupr. 

 in Bull. Acad. roy. Brux. ix, n. 8. (nomen)." Fournier cites four specimens, among 

 them that to .which Ruprecht gave the name, Galeotti's no. 5680. Thia specimen, 

 which, since Ruprecht's name is used, must be taken as the type, ha*~na4r4*M^ft exam- 

 ined. One of the other specimens cited, Botteri's no. 1214, is represented in the 

 National Herbarium by three specimens, one being the scant-bristled, greenish- 

 panicled form (to which the name P. distrehyum is here applied) and two being the 

 many bristled, tawny panicled form described below as P. prolificum. Botteri's 

 numbers are known to be badly mixed. Little reliance can be placed on citations of 



his specimens. Fournier's description is unsatisfac- 

 tory, being mostly a comparison with "O. trutrclnja 

 H. B. K.," which he thinks is but 3 to 4 feet tall, and 

 under which, as shown by the specimens cited, he 

 confused two species, P. distrehyum and the form 

 with longer purplish bristles and spikelets with stanii- 

 nate lower floret which he described as Gymnothrix 

 bambusiformis. But the description of the bristles 

 as not numerous and but little exceeding the spikelet 

 points to the scant-bristled form heretofore called P. 

 tristachyum (H. B. K.) Spreng. 44 by American authors. 



DESCRIPTION. 



Plants perennial; culms 1 to 4 meters tall, robust, 

 glabrous or scabrous below the nodes, mostly solitary, 

 erect or ascending from a decumbent base, often 

 rooting at the geniculate lower nodes, branching from 

 the middle and upper nodes, the primary branches 

 ascending, the secondary and ultimate branehlets 

 spreading or nodding, with 1 to 4 slender-peduncled 

 drooping panicles from each sheath, the whole 

 Fio. 74.-Pennisctum distachyum. forming a top-heavy leafy compound inflorescence; 

 From Botteri 90, Mexico. , , , . ' . , xl ' _ t , 



nodes appressed-hirsute: sheaths loose, mostly shorter 



than the internodes, hirsute along the marein and at the summit or glabrate; 

 ligule stiff, lacerate-ci'iate, 2 to 3 mrn. long; blades flat, mostly spreading, appressed- 

 hirsute on both surfaces or glabrate beneath and sometimes nearly so above, 

 those of the main culm 25 to 45 cm. long, 1.5 to 3.5 cm. wide, narrowed or 

 attenuate at base, the attenuation sometimes elongate, the apex acuminate, but. not 

 setaceous-tipped, those of the branches smaller, lanceolate, rounded or slightly 

 narrowed at ba3e; panicles numerous, dull green, terminal and axillary, the slender 

 flexuous scabrous peduncles unequal, the longest often as much as 15 to 20 cm. long, one 

 of the cluster of panicles usually partly included, the panicles rather densely flowered, 

 3 to 8 cm. long, rarely 10 cm. Ion?, about 1 cm. wide, excluding the Longest bristles, 

 usually tapering to the apex, the longer ones flexuous, the axis slender, angled, 



44 This species based on Gymnothrix tristachya H. B. K. (Nov. Gen. & Sp. 1: 113, 

 1816), described from Fcuador, has less freely branching culms, longer and narrower 

 blades, longer panicles, longer bristles, and larger spikelets. The locality cited with 

 the original description is "prope Puembo * * * regni Quitensis." Mr. Gagne- 

 pain, of the Paris Jlerbarium, states that the Puembo specimen is very poor, but that 

 a specimen from Quito, a panicle and part of a branch of which were kindly sent to the 

 National Herbarium, agrees perfectly with the type. Specimens from Ecuador and 

 Peru agree exactly with this and with the original description and the illustration 

 published later (H. B. K. Nov. Gen. & Sp. 7: pi. 679. 1825). Other specimens com- 

 monly referred to P. tristachyum belong to various allied species. 



