198 NORTH AMERICAN FLORA [Volume 17 



Paspalum mononeurum Steud. Syn. Gram. 24. 1854. Type locality: Oaxaca. 

 Paspalum pubescens Lag. Gen. & Sp. Nov. 2. 1816. Type locality: Havana. 

 Paspalum rudimentosum Steud. Syn. Gram. 24. 1854. Type locality: Oaxaca. 

 Paspalum supinum Rich.; Hornem. Hort. Hafn. 77. 1813. Type locality: Baltimore, 

 Maryland. 



Paspalum taprophyllum Steud. Syn. Gram. 19. 1854. Type locality; Martinique. 

 Paspalum triglume Steud. Syn. Gram. 27. 1854. Type locality: Oaxaca. 



55. PANICUM* L. Sp. PI. 55. 1753. 



Milium Mill. Gard. Diet. Abr. ed. 4. 1754. Not Milium L. 1753. 



Urochloa Beauv. Agrost. 52. 1812. 



Eatonia Raf. Jour, de Phys. 89: 104. 1819. 



Talasium Spreng. Syst. 4: Cur. Post. 22. .1827. 



Thalasium Spreng. Syst. 4: Cur. Post. 30. 1827. 



Eriolytrum Desv.; Kunth, R6v. Gram. 219. 1830. 



Steinchisma Raf. Bull. Bot. Seringe 220. 1830. 



Dilencaden Raf.; Steud. Norn. Bot. ed. 2. 1: 508. 1840. 



Steins chisma Raf.; Steud. Nom. Bot. ed. 2. 2: 635. 1841. 



Phanopyrum Nash, in Small, Fl. SE. U. S. 104. 1903. 



Chasea Nieuwl. Am. Midi. Nat. 2: 63, 64. 1911. 



Annual or perennial grasses, of various habit, the perennial species tufted or with creeping 

 rhizomes. Inflorescence usually a panicle, sometimes a series of spike-like more or less 1 -sided 

 racemes; panicles usually open, sometimes contracted, the branchlets symmetrically arranged 

 or aggregated along one side of the main branches. Spikelets (in spicate inflorescences) placed 

 with the back of the fruit toward the rachis, articulated below the glumes, rarely also below the 

 fruit, more or less compressed dorsoventrally, consisting of one perfect terminal floret and a 

 second staminate or neuter floret below. Glumes* 2, herbaceous, nerved, usually very unequal, 

 the first sometimes minute, the second typically equaling the sterile lemma, the latter of the 

 same texture and simulating a third glume, bearing in its axil a membranaceous or hyaline 

 palea and sometimes a staminate flower, the palea rarely wanting; fertile lemma chartaceous- 

 indurated, typically obtuse, the nerves obsolete, the margins inrolled over an inclosed palea 

 of the same texture, a lunate line of thinner texture at the back just above the base, the root 

 protruding through this at germination. Stamens 3. Styles 2. Stigmas plumose. Grain 

 dorsoventrally compressed, with a punctiform hilum, free within the firmly closed lemma and 

 palea. 



Type species, Panicum miliaceum L. 



Axis of branchlets extending beyond the base of the uppermost 



spikelet as a point or bristle 1-6 mm. long. I. Distantiflora. 



Axis of branchlets not extending into a bristle. (In Panicum 

 geminatum and P. paludivagum the somewhat flattened axis 

 pointed but not bristle-form.) 

 Basal leaves usually distinctly different from those of the culm, 

 forming a winter rosette (except in PedicEM^ata and 

 Cordovensia) ; culms at first simple, the spikelets of the 

 primary panicle not perfecting seed, later usually becoming 

 much -branched, the small secondary panicles with cleisto- 

 gamous, fruitful spikelets; panicles open, the branchlets 

 usually flexuoiis; perennials. 

 First glume nearly as long as the spikelet; fruit apiculate. XL. Cordovensia. 



First glume much shorter than the spikelet. 



Leaf -blades elongate, not more than 5 mm. wide, 20 

 times as long as wide; autumnal phase branching from 



the base only (from the lower nodes in P. Werneri). XXIII. Depauperata. 



Leaf -blades not elongate (or if so, more than 5 mm. wide 



and autumnal phase not branching from the base). 



Plants branching from the base, finally forming 



rosettes or cushions, the foliage soft and lax; leaf- 



blades prominently ciliate except in P. laxiflorum. XXIV. LaxieivOra. 



Plants branching from the culm-nodes or rarely re- 

 maining simple. 

 Leaf -blades long, stiff; autumnal phase bushy - 

 branched above. 



*From this point on the treatment of the Poaceae is by Albert Spear Hitchcock. Pub- 

 lished by permission of the Secretary of Agriculture. 



