MANUAL OF THE GRASSES OF THE UNITED STATES 727 



144. PENNISETUM L. Rich. 



Spikelets solitary or in groups of 2 or 3, surrounded by an involucre of 

 bristles (sterile branchlets), these not united except at the very base, often 

 plumose, falling attached to the spikelets; first glume shorter than the spikelet, 

 sometimes minute or wanting; second glume shorter than or equaling the sterile 

 lemma; fertile lemma chartaceous, smooth, the margin thin, enclosing the 

 palea. Annuals or perennials, often branched, with usually flat blades and 

 dense spikelike panicles. Type species, Pennisetum typhoideum L. Rich. (P. 

 glaucum). Name from Latin penna, feather, and seta, bristle, alluding to the 

 plumose bristles of some species. 



The most important species is P. glaucum, pearl millet, which is widely 

 cultivated in tropical Africa and Asia, the seed being used for human food. 

 It has been cultivated since prehistoric times, its wild prototype being un- 

 known. In the United States pearl millet is used to a limited extent in the 

 Southern States for forage, especially for soiling. Two species, P. villosum 

 and P. setaceum, are cultivated for ornament. An African species, P. purpur- 

 eum, elephant or Napier grass, is used in Florida as a forage plant. 



Plants annual; bristles of involucre about as long as the spikelets. Cultivated. 



1. P. GLAUCUM. 



Plants perennial ; bristles much longer than the spikelets. 



Culms extensively creeping; spikelets few, hidden in the upper sheath. 



6. P. CLANDESTINUM. 



Culms not creeping; panicle exserted. 

 Longer bristles 1 cm. long. 



Bristles unlike, the inner silky, plumose 2. P. setosum. 



Bristles all scabrous 3. P. nervosum. 



Longer bristles 3 to 4 cm. long, the panicles feathery. 



Panicle oval, tawny 4. P. villosum. 



Panicle elongate, purple or rosy 5. P. setaceum. 



1. Pennisetum glaucum (L.) R. 



Br. Pearl millet. (Fig. 1109.) An- with sparsely plumose bristles about 



nual; culms robust, as much as 2 m. 1 cm. long. % — Introduced from 



tall, densely villous below the panicle ; Africa; used as a forage plant from 



blades flat, cordate, sometimes as central to southern Florida ; grown in 



much as 1 m. long and 5 cm. wide; the West Indies and South America, 



panicle cylindric, stiff, very dense, Also called elephant grass, 



as much as 40 to 50 cm. long and 2 2. Pennisetum setosum (Swartz) 



to 2.5 cm. thick, pale, bluish-tinged, L. Rich. (Fig. 1110.) Perennial; culms 



or sometimes tawny, the stout axis sometimes 30 or more in loose clumps, 



densely villous; fascicles peduncled, 1 to 2 m. tall, geniculate, sometimes 



spikelets short-pediceled, 2 in a fas- rooting at the lower nodes, bearing 



cicle, 3.5 to 4.5 mm. long, obovate, 1 to several flowering branches from 



turgid, the grain at maturity pro- the lower and middle nodes, scabrous 



truding from the hairy-margined lem- below the panicle ; blades elongate, 4 



ma and palea. (P. typhoideum L. to 18 mm. wide; panicle 10 to 25 



Rich.; Penicillaria spicata Willd.) — cm. long, 8 to 10 mm. thick, excluding 



Cultivated to a limited extent in the the bristles, rather dense, yellow to 



Southern States for forage; Eastern purple; fascicles reflexed at maturity; 



Hemisphere. bristles unequal, the outer delicate, 



Pennisetum purpureum Schumach. mostly shorter than the spikelet, the 



Napier grass. Robust leafy peren- inner densely silky-plumose below, as 



nial, 2 to 4 m. tall; blades elongate, much as 1 cm. long, the hairs beauti- 



2 to 3 cm. wide; panicle dense, fully crimped; spikelet solitary, 3.2 



elongate, stiff, tawny or purplish, to 4 mm. long; fruit subindurate, 



