Panicum. 



GRAMINE.E. 



423 



11. PANICUM. Linn, (in part); Endl. gen. 770 (including Oplismenus). PANIC-GRASS . 



[ Said to be derived from panis, bread ; the grain of some species being used for food ] 



Spikelets 2-flowered, naked ; the flowers with or without awns. Glumes 2, mostly very un- 

 equal, membranaceous, concave. Lower flower of one or two palea?, staminate or neuter, 

 membranaceous. Upper flower perfect ; the paleas 2, coriaceous, nearly equal, concave. 

 Stamens 3. — Grasses of various habit ; the inflorescence mostly paniculate or spiked : 

 rachis not jointed. 



* Digitaria, Scop. Spikes linear, unilateral, digitate, fasciculate or paniculate : flowers not owned. 



1. Panicum sanguinale, Linn. (Plate CXLVI.) Common Crab-grass. 



Spikes digitate, erect-spreading ; leaves and sheaths somewhat hairy ; spikelets oblong ; 

 flowers pubescent on the margin. — Linn. sp. 1. p. 57 ; Engl. hot. >. 849 ; Bigel. fl. Bost. 

 p. 41 ; Trin. gram. Pan. p. 78, and ic. t. 93 & 94 ; Kunth, enum. 1. p. 82. Digitaria 

 sanguinalis, Scopol. ; Michx. fl. 1, p. 45 ; Pursh, fl. 1. p. 69 ; Mulil. gram. p. 120 ; Ell. 

 sk. 1. p. 121 ; Torr. fl. 1. p. 154 ; Beck, hot. p. 398 ; Darlingt. fl. Cest. p. 44. Syn- 

 therisma prascox, Walt. fl. Car. p. 76. 



Annual. Culm 1-2 feet long, assurgent or decumbent, branching at the base and rooting 

 at the lower joints. Leaves often undulate on the margin. Spikes 4 - 6, or sometimes more : 

 rachis flexuons. Spikelets in pairs, on short peduncles, arranged in two rows on one side of a 

 very narrow flexuous rachis, to which they are closely appressed : inferior spikelet almost 

 sessile. Lower glume very minute ; the upper lanceolate, acute. Abortive flower without 

 any trace of a superior palea : inferior palea much longer than the glume. Perfect flower 

 very smooth, nearly orbicular. 



Cultivated grounds, sandy fields, etc. : very common. Fl. August October. A trouble- 

 some weed in gardens, and doubtless a naturalized foreigner. 



2. Panicum glabrum, Gaud. Smooth Crab-grass. 



Spikes digitate, somewhat alternate (3 - 4), spreading ; leaves and sheaths smooth ; spike- 

 lets ovoid, crowded ; inferior glume almost wanting, superior as long as the abortive flower, 

 the two latter hairy. — "Gaud. Agrost. 1. p. 22 ; " Trin. diss. 2. p. 83, ic. gram. 13. t. 149, 

 and Pan. gen. 1. c. p. 203 ; Kunth, enum 1. p. 83. Digitaria glabra, Rcem. <|- Schult. syst. 

 2. p. 471 ; Torr. fl. 1. p. 154, excl. syn. Michx. D. humifusa, Pers. syn. 1. p. 85. D. 

 Ischasmum, Schreb. ; Mulil. gram. p. 121. 



Annual. Culm about a foot long, mostly decumbent, rarely rooting at the joints. Leaves 

 sometimes with a few hairs on the upper surface. Spikes mostly 3, about two inches long. 

 Lower glume wanting. Palea of the abortive flower 5-nerved, hairy. Perfect flower smooth : 

 paleae finely striate. 



Sandy fields : not rare. Fl. Aug.- September. Perhaps introduced from Europe : certainly 

 identical with the foreign plant. The lower glume is extremely minute, and easily overlooked. 



