276 MISC. PUBLICATION 243, U.S. DEPT. OF AGRICULTURE 
Purerto Rico: Mayaguez, Sintenis 357. Cerro Gordo, Sintenis 
2609. Maricao, Chase 6199, 6250 (Amer. Gr. Nat. Herb. 211). 
Adjuntas, Chase 6469. 
51. Panicum rudgei Roem. and Schult., Syst. Veg. 2: 444. 1817. 
Based on P. scoparium Rudge. 
Panicum scoparium Rudge, Pl. Guian. 1: 21. pl. 29. 1805. Not 
“P. scoparium Lam., 1798. British Guiana. 
Perennial; culms robust, 30 to 100 cm tall, erect or somewhat 
geniculate; sheaths hirsute; blades thick, linear, 15 to 40 cm long, 5 
to 10 mm wide, rather rigidly ascending, flat or folded, usually densely 
hirsute; panicles terminal and lateral, forming an oblong inflorescence, 
open, the branches stiff, the pedicels divaricate; spikelets 3.5 mm 
long, turgid, strongly nerved, sparsely hirsute; glumes and sterile 
lemma acuminate or abruptly pointed (fig. 245). 
Savannas at low and medium altitudes, Central America and 
Jamaica to Brazil. 
FIGURE 245.—Panicum rudgei. Two views of FIGURE 246.—Panicum mertensii. 
spikelet, and floret, X 10 (Salzmann). Spikelet and floret, X 10 (type of 
P. altissimum Meyer). 
Jamaica: Upper Clarendon, Harris 12235, 12845. Bunkers Hill 
Savanna, Harris 11170. Bull Head Mountain, Mitchcock 9528. 
TRINIDAD: Piarco Savanna, Britton and Hazen 688. O’Meara 
Savanna, Britton and Hazen 1563. Pitch Lake, Hitchcock 10083 
(Amer. Gr. Nat. Herb. 75). St. Joseph, Hitchcock 10181. Without 
locality, Crueger. 
52. Panicum mertensii Roth, in Roem. and Schult., Syst. Veg. 2: 
458. 1817. British Guiana. 
Panicum altissimum Meyer, Prim. Fl. Esseq. 63. 1818. Not P. 
altissimum DC., 1813. British Guiana. 
Panicum megiston Schult., Mant. 2: 248. 1824. Based on P. 
altissimum Meyer. 
Perennial; culms robust, 1 to 2 m tall; sheaths papillose-hispid; 
blades elongate, 1.5 to 3 em wide, glabrous; panicles 40 to 60 cm 
long, the stiff main axis striate-angled, the branches in distant verticils 
as many as 20 to 30 in a verticil; spikelets about 3.5 mm long, globular- 
obovoid, glabrous; first glume less than one-third the length of the 
spikelet (fig. 246). 
Swamps and banks of ponds and rivers, Mexico and Trinidad to 
Paraguay; Cuba. : 
