808 OBDEB 156. GR AMINES. 



cellatc, 2-flowcred, lower fl. neuter with a single pale, upper fl. perfect, 

 of 2 pales ; gl. subequal, awnless ; pales thia and hyaline, awnless ; 

 stam. 1 to 3. 2 Gigantic, tropical Grasses with branching panicles. 

 Spikelets cinctured at base with long silky hairs. 



S. officinarum L. Culm solid with pith, closely jointed, 8 2 Of, erect, with 

 many broad, flat, linear-lanceolate leaves ; panicle 1 to 2f in length, composed of 

 numerous long, filiform loosely erect-spreading racemes, richly clothed with the 

 long white silky involucrate hairs. Native in S. Asia. Among sugar plants 

 this still holds the preeminence. Its delicious product, now the indispensable 

 luxury of tho world, was unknown to the ancients. It is propagated from cut- 

 tings of the rhizome, and seldom permitted to waste its sweetness in flowering. 



69. ANDROPCTGON, L. BEARD GRASS. (Gr. avdpo^ a man's, Trwywi', 

 beard.) Spikelets in pairs at each joint of a slender rachis, one on a 

 plumous-bearded pedicel, incomplete, the other sessile, 2-flowered ; 

 lower flower of 1 empty pale ; upper ', pales thin, hyaline, the lower 

 of the tipped with an awn ; glumes subcoriaceous ; stamens 1 to 3 ; 

 grain free. 21 Coarse Grasses. Inflor. various. 



Inflorescence in a naked (leafless) panicle. Sterile spikelet a mere pedicel No. 1 



js Inflorescence in distinct spikes exserted from the sheaths, (a) 



a Sterile spikelets nothing but barren pedicels. Spikes sheathed at base. . . .Nos. 2, 3 

 a Sterile spikelets with glumes on the pedicels, (b) 



b Spikes silvery white, in conjugate pairs No. 4 



b Spikes digitate, 2 to 5, brownish Nos. 5, 6 



b Spikes single, terminal, one on each branch Nos. 7. 8 



$ Inflorescence spicate, enclosed in the sheaths Nos. 9, 10 



1 A. nutans L. INDIAN GRASS. "Wooo GRASS. Culm simple, 3 to 6f, erect, 

 with smooth sheaths and glaucous Ivs. ; pan. rather dense, oblong, slender, at 

 length nodding; spikelets in pairs or 3s, apparently pedicellate, but the fertile is, 

 in fact, sessile as in the other species, all tawny, the sterile reduced to mere pedi- 

 cels in contact with the 5 , clothed with short bristles ; 5 spikelet bristly-ciliate, 

 with a ring of bristles at base, and tipped (the lower pale) with a contorted awn. 

 Sandy fields or woods. Can., N. Y. to Ga. and La. (A. avenaceus MX. A. 

 oiliatus E1L Sorghum, Gray.) 



2 A. macrurus MX. Culm 2 to 3f erect, much branched and bushy ; Ivs. long, 

 linear, upper spathiform, lance-linear ; racemes small, very numerous, fascicled at 

 the upper joints forming a large leafy and silky panicle; spkl. minute, with a 

 straight bristle-liko awn, the neutral only a fine pedicel merely, with white, silky 

 hairs half as long (3 4") as the awn; stam. 1. Damp soils, S. States. Sept., 

 Oct. 



3 A. virginicus L. Culm tall (3 to 6f ) compressed, more or less downy with 

 scattered hairs as well as the long and narrow, carinate Ivs. ; upper half diffusely 

 paniculate; spikes conjugate, soft, feather-like, hardly as long (8 to 12'') as their 

 bract ; abort, fl. a mere capillary pedicel, longer than the fl. with thin silky 

 white hairs half as long as the straight similar awn. Dry soils, S. States, commoa 

 Oct. (A. dissitiflorus MX.) 



/?. VAGINA TUS differs only in its fewer, shorter spikes and longer bracts which 

 often much exceed them. (A. vagin. E1L) 



4 A. argenteus Ell. Culm purplish, slender, much branched, glabrous, branches 

 mostly solitary, spikes conjugate, 1 to \\' long, exserted beyond the sheath; spkl. 

 appressed to the rachis ; abortive fl. a minute, subulate glume on a thick ped. 

 appressed to the $ , its fawn-white hairs copious, half the length of the roughish, 

 brown awn. Dry soils, S. States. The silvery hairs conceal the fls. 



5 A. furcatus MuhL FORKED SPIKE. St. semiterete above, 4 7f high ; Ivs. 

 lance-linear, rough-edged, radical ones very long; spikes digitate or fasciculate, in 

 2s 5s, 3 5' long, purple ; spikelets appressed, abortive one on a plumous pedicel, 



$ with 2 palese, awnless, perfect one with 2 unequal glumes; lower palea bifid, 

 awned between the divisions. 1 Meadows and low grounds, Can., N. Y. to Ga. 

 and W. States. Aug. (A. ternarius MX.) 



6 A. tetrastychus Ell. Culm glabrous, 2 to 3f erect, with long, keeled, very 



