Spartina. GRAMINE^E. 289 



involute. The triple awn separates the genus from Stipa, which it in other respects much re- 

 sembles. In the Eastern States Aristida is represented by about a dozen species, while Stipa has 

 but three ; upon the Pacific Coast these numbers are very nearly reversed. In the division of 

 the genus, those having the persistent straight awn continuous with and divided down to the 

 palet are placed in the section Ckcetnria. Those with the awn divided above and twisted below 

 to form a stipe, which is articulated with the palet and caducous, form the section ArthratJterum, 

 which is regarded by some as a genus. 



1. A. bromoides, HBK. Culms from 3 to 12 inches high, forming close tufts, 

 slender and often geniculate below : radical leaves few and short ; those of the culni 

 two, 1 or 2 inches long, involute-setaceous and rather rigid, smooth below, minutely 

 scabrous above ; ligule minute, fringed ; sheaths shorter than the iuternodes : pani- 

 cle 1 to 3 inches long, spike-like, somewhat secund, the rays solitary or clustered, 

 branched nearly to the base : spikelets purplish, 4 to 5 lines long, on shorter pedi- 

 cels : glumes narrow, mucronate, scabrous on the back, the lower about 2 lines long, 

 the upper twice its length : floret mostly equalling the upper glume, its short callus 

 with brief, very white hairs ; lower palet greenish with numerous dark purple 

 blotches, smooth except on the scabrous midnerve ; middle awn rather longer than 

 the palet, the lateral ones somewhat shorter, all minutely scabrous ; upper palet very 

 short, scarcely exceeding the ovary. Nov. Gen. & Spec. i. 122. A. dispersa, var. 

 bromoides, Trin. & Rupr. Stipaceae, 130. 



Colorado Desert (Schott) ; San Diego (Bolander) ; Sonora, New Mexico and Texas ; Quito. A 

 variable species, forms of which have been described under several names ; these have been brought 

 together by Trinius and Ruprecht as varieties of one species, to which they gave a new name 

 A. disperse/,. In this case it seems proper to continue one of the older names. The plant is 

 probably an annual, though none of the specimens have roots. The same tuft has culms from 3 

 inches to a foot high ; in the shorter ones the base of the panicle is included, but in the taller it 

 is long exserted. In the young plant the panicles are dark purple ; in older specimens, they be- 

 come light brown. 



2. A. Californica, Thurber. Culms '5 to 10 inches high, very densely tufted, 

 geniculate below and branched above, pubescent, especially at the nodes : leaves 

 involute, pubescent above, scabrous below, the radical from 1 to 1| inches long, 

 those of the culm shorter, the uppermost minute or reduced to a mere sheath ; ligule 

 a fringe of hairs ; sheaths shorter than the internodes, loose, striate, pubescent or 

 hirsute : panicle 1 or 2 inches long, racemose, few-flowered, the lower spikelets in 

 pairs (one sessile, the other short-pedicelled), the upper solitary : glumes scabrous on 

 the keel, lacerate-fringed at apex, usually purple with white margins, the lower 4, 

 the upper 6 lines long : floret shorter than the lower glume, with a conspicuous 

 white-hairy callus one-third its length ; lower palet minutely scabrous, especially 

 above, pale greenish and marked with purplish-black blotches, the upper palet about 

 one-fourth as long ; awns about equal, very slender, minutely scabrous, 1 to 2 inches 

 long, twisted below into a slender stipe (5 to 8 lines long), which is articulated with 

 the upper palet and deciduous at maturity. Bolander in Trans. Calif. Agric. Soc. 

 1864-65, 134, without description. 



Colorado Desert (Schott} ; Fort Mohave, Cooper. Apparently an annual, which by its numerous 

 branches and long awns forms a complex tuft. It is the only species of the section with articu- 

 lated, caducous awns (Arthratherum) thus far found in North America. According to Mr. Schott 

 it is known to the Mexicans as Zacate dc licbre, " Hare's-grass. " 



27. SPARTINA, Schreb. CORD-GRASS. 



Panicle of mostly erect racemed spikes. Spikelets crowded in two rows upon one 

 side of a triangular rhachis, subsessile, 1 -flowered with no rudiment, much flattened 

 laterally. Glumes rigid, more or less rough-bristly on the strongly compressed keel, 

 acute or short-awned. Floret sessile, shorter than the upper glume. Lower palet 

 membranaceous or chartaceous, awnless, the upper slightly longer. Scales none. 

 Stamens 3. Ovary smooth : styles very long, more or less united below ; stigmas 



