248 



GRAMINEAE. 



VOL. I. 



i. Pleuropogon Sabinii R. Br. Sabine's 



Pleuropogon. Fig. 595. 



P. Sabinii R. Br. App. Parry's Voy. 289. 1824. 



Smooth, culms 6' or less tall, erect, simple, 

 glabrous. Sheaths one or two; ligule i" long; 

 blades i'-i' long, erect, glabrous; raceme I'-z' in 

 length; spikelets 3-6, 5-8-flowered, about 5" long, 

 on spreading or reflexed pedicels i" or less in 

 length ; lower scales smooth, the first acute, shorter 

 than the obtuse second; flowering scales oblong, 

 2"-2\" long, erose-truncate at the scariotts sum- 

 mit, scabrous, the midnerve sometimes excurrent 

 as a short point; palet slightly shorter than the 

 scale, truncate and somewhat 2-toothed at the 

 apex, bearing an awn-like appendage on each keel 

 near the middle. 



Arctic regions of both the Old World and the New. 

 Summer. 



87. UNIOLA L. Sp. PL 71. 1753. 



Erect and often tall grasses with flat or convolute leaf-blades and paniculate inflorescence. 

 Spikelets 3-many-flowered, flat, 2-edged, the flowers perfect, or the upper staminate. Scales 

 flattened, keeled, sometimes winged, rigid, usually acute ; the lower 3-6 empty, unequal ; the 

 flowering scales many-nerved, the uppermost scales often smaller and empty; palets rigid, 

 2-keeled. Stamens 1-3. Styles distinct. Stigmas plumose. Grain compressed, free, loosely 

 enclosed in the scale and palet. [Name diminutive of units, one, of no obvious application.] 



About 10 species, natives of America. Besides the following, 2 others occur in the southeastern 

 United States. Type species: Uniola paniculata L. 



Spikelets about %' in length; panicle spike-like. i. U.la.va. 

 Spikelets exceeding l / 2 ' in length ; panicle open. 



Panicle lax. the branches pendulous ; spikelets on long capillary pedicels. 2. U. latifolia. 



Panicle strict, the branches erect, rigid; spikelets on short stout pedicels. 3. U. paniculata. 



i. Uniola laxa (L.) B.S.P. Slender Spike-grass. Fig. 596. 



Holcus laxus L. Sp. PI. 1048. 1753. 



Uniola gracilis Michx. Fl. Bor. Am. i : 71. 1803. 



Uniola laxa B.S.P. Prel. Cat. N. Y. 69. 1888. 



Smooth and glabrous, culms i2-4 tall, 

 erect, simple, slender. Sheaths shorter than 

 the internodes ; ligule very short; blades 5'-i5' 

 long, i "-3" wide, usually erect, flat, attenuate 

 into a long tip, smooth or slightly rough ; pan- 

 icle spike-like, 4'-i2 f in length, erect, strict, or 

 nodding at the summit, the branches erect, 

 I '-2' long; spikelets short-stalked or nearly 

 sessile, 3-6-flowered, about 3" long; lower 

 scales much shorter than the flowering ones, 

 which are \\"-2" long, acuminate, spreading 

 in fruit ; palet arched, about two-thirds as long 

 as the scale; stamen i. 



Sandy soil. Long Island to Kentucky, south to 

 Florida and Texas, mostly near the coast. As- 

 cends to 900 ft. in North Carolina. Union-grass. 

 Aug.-Sept. 



