GKAMINEAE (GBASS PAMILYJ 



m 



larger, glumes many-nerved ; sterile lemma- subrigid ; 

 fertile lemma and palea much indurated, acuminate, 

 margins of lemma neither hyaline nor inroUed. — Erect 

 annuals or perennials with flat leaves. (Name from 

 AfKplKapiros,^ doubly fruit-hearing.) 



1, A. Piirshii Kunih. Annual ; culms erect, branch- 

 ing, 3-6 dm. high; sheaths and blades coarsely hispid; 

 terminal panicle contracted ; spikelets about 4 mm. long ; 56. A. Purshii. 



fertile spikelets solitary, about 6 mm. Ions;, at the ends sterile spikelet closed x a 

 of the slender subterranean branches. {Milium Amphi- Same wide open x 2. 

 tarpon Pursh ; A. Amphicarpon Nash.) — Moist sandy Basal fertile apikelet, 

 pine barrens, N. J. to Fla. Sept. Fig. 60. partly open x2. 



9. PASPALUM L. 



Spikelets 1-flowered, plano-convex, nearly sessile, solitary or in pairs, in 2 

 rows on one side of a continuous narrow or dilated rhachis, forming simple spike- 

 like racemes ; spikelets placed with the back of the fertile lemma toward the 

 rhachis; first glume obsolete (rarely present); lemma and palea chartaceous- 

 indurated, margins of the lemma inroUed. — Perennials, with 1-several racemes 

 digitate or racemose at the summit of the culm and branches. (Ilao'jrdXos, a 

 Greek name for millet.) 



ct. Racemes l-several, 1 terminal and often 1 or more lateral b. 

 h. Rhachis membranaceous, 2 mm. or more broad. 



Spikelets 1.5 mm. long, elliptical, pubescent . . ■ . i. ^, mucronal/wm. 



Spikelets 2 mm. long, oval, glabrous 2. P. disseotum. 



?. Rhachis narrow, not membranaceous, less than 1 mm. broad 

 (except in P. Boseianum) c. 

 0. Axillary peduncles 1 or more from uppermost sheath ; leaves" 

 ciHate on the margin d. 

 d, Spikelets 2 mm. long e. 



e. Leaves glabrous on both surfaces 5. 



e. Leaves pubescent on one or both surfaces f. 

 /. Spikelets glabrous. 



Leaves densely long-pubescent. 

 Culm hirsute below raceme ... 



Culm glabrous 



Leaves puberulent and sometimes sparsely villous 

 f, Spikelets pubescent ; leaves short-pubescent. 



Culms erect 



Culms prostrate ■ . 



d, Spikelets 1.5 mm. long. 



Spikelets glabrous 



Spikelets pubescent 



C. Axillary peduncles none g. 

 g. Spikelets glabrous h. 

 h. Spikelets singly disposed so as to appear in 1-2 rows. 

 Spikelets 2.5 mm. long. 

 Plants glabrous or sparingly pilose. 

 Leaf-blades of culm 1-2 dm. long ; racemes 8-5 



cm. long 11. P. la&ce. 



Leaf-blades of culm 2-4 dm. long; racemes 8-10 



cm. long 12. 



Plants with pubescent sheaths and blades . . .13. 

 Spikelets 3 mm. long; sheaths papillose-hirsute . . 14. 

 Spikelets 4 mm. long. 

 Leaf-blades less than 1.5 dm. long . . , .16. 



Leaf-blades 2-4 dm. long 15. 



h. Spikelets in pairs so as to appear In four rows. 



Spikelets stramineous at maturity , . • , .17. 



Spikelets dark brown at maturity 18. 



g. Spikelets ciliate 19. 



a. Racemes a pair at the summit of the culm ... .20. 



P. pubeacens. 

 P. MuhlenbergU, 

 P. stramineum. 



P* Buehii. 



p. psarnmophilv/m, 



P. longipeduneulaittm 

 P- Betac&wm, 



P. anguslifoTAwm^ 

 P. plenipilum, 

 P. circulare. 



P. dijfoT'me. 

 P, Jloridanum, 



P. laeviglume, 

 P. Boseianum, 

 P. dzlataium. 

 P, distichum. 



* Bacemes with a hroad^ thin-memhranaceous, orfoliaceous and keeled^ rhachis, 

 2 mm. wide or more, the incurved margins partly inclosing the small 2-rowed 

 bpikelets. {Aquatic or nearly so, decumbent or floating.) 

 1. P. mucronatum Muhl. Sheaths papillose-hirsute or nearly smooth, in- 

 flated ; blades lanceolate, 2.5-15 cm. long, 6-1^ mm. wide, scabrous; racemes 

 10-~50, finally spreading ; rhachis extending beyond the spikelets, which are ellip' 



gray's MANUAi. — 7 



