GRAMINE^K. (GRASS FAMILY.) 607 



« * Spikelets manifestly 1 J - 2-flowered (polygamous, the lower flower staminate or often 

 neutral, of one or both palets), the lower glume being present. 



60. Panicum. Spikelets not involucrate, nor the peduncles bristle-bearing. Lower glume 



usually small or minute. Sterile flower either stamiuate or neutral. 



61. Setaria. Spikelets spiked or dense-panicled, the peduncles continued iuto naked solitary 



bristles or awns : otherwise as iu Panicum. 



62. Ce ncbrus. Spikelets enclosed 1-5 together in a hard and spiny or bristly and globular 



bur-like involucre. 



Subtribe 'Z. Saccbarcee. Fertile palets membranaceous or scarious, always of thinner 

 and more delicate texture than the (often indurated) glumes, frequently awned from the 

 tip. Spikelets usually in pairs or threes, panicled or spiked, some of them entirely sterile 

 or rudimentary. 



* Spikelets monoecious, imbedded in the separable joints of the spike. 



63. Tripsaeum. Staminate spikelets above, in pairs at each joint: pistillate spikelets sin- 



gle iu each joint : glumes indurated. 

 * * Fertile spikelets with one perfect and one sterile (staminate or mostly neutral) flower: 

 lower paiet of the perfect flower awned. 



64. Erianthus. Both spikelets at each joint of the rhachis alike fertile, and involucrate 



with a silky tuft: otherwise as in the next. 



65. Andi-npuguii. Spikelets a pair at each joint of the plumose-hairy spikes, one of them 



sessile and fertile ; the other pedicelled and sterile or rudimentaiy. 



66. Sorghum. Spikelets in open panicles, 2-3 together, the lateral ones sterile or some- 



times reduced to mere pedicels. 



1. LEERSIA, Solander. White Grass. (PL 7.) 



Flowers crowded in one-sided panicled spikes or racemes, perfect, but those in 

 the open panicles usually sterile by the abortion of the ovary, those enclosed in 

 the sheaths of the leaves close-fertilized in the bud and prolific. Spikelets 

 1 -flowered, flat, more or less imbricated over each other, jointed with the short 

 pedicels. Glumes wanting. Palets chartaceous, strongly flattened laterally 

 or conduplicate, awnless, bristly-ciliate on the keels, closed, nearly equal in 

 length, but the lower much broader, enclosing the flat grain. Stamens 1-6. 

 Stigmas feathery, the hairs branching. — Perennial marsh grasses : the flat 

 leaves, sheaths, &c, rough upwards, being clothed with very minute hooked 

 prickles. (Named after John Daniel Leers, a German botanist.) 

 * Spikelets narrowly oblong, rather loosely crowded. 



1. L. Virginioa, Willd. (White Grass.) Panicle simple; the spikelets 

 closely appressed on the slender branches, around which they are partly curved 

 (l£" long) ; stamens 2 (a third imperfect or wanting) ; palets sparingly ciliate 

 (greenish-white). — Wet woods. Aug., Sept. 



2. L. oryzoides, Swartz. (Rice Cut-grass.) Panicle diffusely branched ; 

 spikelets flat, rather spreading (2^" -3" long) ; stamens 3; palets strongly bristly- 

 ciliate (whitish). — Very wet places : common. Aug. (Eu.) 



* * Spikelets broadly oval, imbricately covering each other (2^" -3" long). 



3. L. lentieularis, Michx. (Fly-catch Grass.) Smoothish; panicle 

 simple; palets very flat, strongly bristly ciliate (said to close and catch flies) ; 

 stamens 2: otherwise like the preceding. — Low grounds, Virginia, Illinois, 

 and southward. 



