90 GRAMINEAE 



6. PASPALUM L. 



Spikelets l-tiowered, phmo-oonvex. nearly sessile, placed with the back of 

 the fertile lemma toward the rachis, solitary or in pairs, in 2 rows on 1 side of 

 a continuous narrow or dilated rachis, forming simple spike-like racemes. 

 First glume usually obsolete (often present in our species). Second glume and 

 sterile lemma membranaceous, about as long as the indurated fertile lemma. 

 Perennials, with 1 to several racemes at the summit of the culm and branches. — 

 Species numerous, probably 200, in the warmer parts of both hemispheres. 

 (Paspalos, a Greek name for millet.) 



1. P. distichum L. I'ulms erect from a decumbent rooting base, with numer- 

 ous creeping rhizomes, glabrous, or the nodes pubescent, 1 to 2 feet high; 

 sheaths glabrous or sometimes pubescent; blades flat, glabrous, rarely pu- 

 bescent, 2 to 4 inches long, the upper shorter ; racemes 2, the second 4 to 5 lines 

 below the first, sometimes a third below the second, more or less pilose at base, 

 slender, ascending or appressed, usually 1 to 2 inches long; spikelets ellip- 

 tical, 11/2 lines long; first glume sometimes wanting, sometimes nearly as long 

 as spikelet, glabrous; second glume pubescent; sterile lemma glabrous. 



Along the seacoast (Crescent City, Davy tO Blasdale 5937) and in ditches and 

 wet places in the interior, central and southern portions of the state (Pierced, 

 Hitchcock 3211; Los Angeles, Grant 1196); rarely northward. Common in 

 tropical America and extending north in the Eastern coastal plain as far as 

 Virginia. 



Refs. — Paspalum distichum L. Syst. Nat. ed. 10. 2: 855. 1759; Thurb. in Wats. Bot. 

 Cal. 2: 257. 1880; Da\-y in Jepson, Fl. W. Mid. Cal. 30. 1901; Abrams, Fl. Los Ang. 22. 1904. 

 Panicum ■polyrhizum Presl, Eel. Haenk. 1: 296. 1830, the type from "Monte-Key", Cal., is 

 in the herbarium of the German University at Pra^'iie. 



7. PANICUM L. 

 Spikelets with 1 perfect flower and a staminate or neutral flower below. 

 Glumes unequal, first often minute, second usually about equaling the sterile 

 lemma, the latter usually enclosing a palea and sometimes a staminate flower. 

 Fertile lemma and palea indurated, the former inrolled at the margins. Annuals 

 or perennials of various habit, with spikelets borne in panicles. — Species numer- 

 ous, probably 350, in the warmer regions of both hemispheres. (An ancient 

 Latin name for the millet, Setaria italica.) 



Plants annual. 



Fruit transversely rugose 1. P. arizonirum. 



Fruit smooth. 



First glume not over % the length of the spikelet, truncate or broadly triangular; sheaths 



smooth 2. P. dicliotomifiorum. 



First glume as much as i-o the length of the spikelet, acute or acuminate; sheaths hispid. 



Panicle drooping 6. P. miliaceum. 



Panicle erect. 



Panicle more than i^ the length of the entire plant. 



Spikelets 1 to H4 lines long 3. P. capiUnre. 



Spikelets 1% to 1% lines long 4. P. barbipulvinatum. 



Panicle not more than y^ the entire height of plant; spikelets 1% to 1% lines long. 



5. P. hirticaule. 

 Plants perennial. 



Spikelets 3 to 3% lines long 7. P. urvilleanum. 



Spikelets % to 1% lines long. 



Spikelets turgid, strongly nerved, sparsely hispid, 1% lines long... 14. P. scribnerianum. 

 Spikelets not turgid or strongly nerved, pubescent, not over IVU lines long, 



Spikelets about 1% lines long 13. P. sluutense. 



