160 PANICACE^. 



a. Spike cylindrical, burs containing 3-5 spikelets, with a row 



of barbed bristles below the spikes 3 



a. Burs 6-20 or more, 1 cm. long including spines. ... 4 



a. Burs 2-3, 2-3 cm. diam. including stout spines ... 5 



1. C. myosuroides H. & K. Nov. Gen. et Sp. 1: 115, t. 35 

 (1815). Pennisetiim myos2iroides Sjireng. Syst. 1:303 (1824). 



An erect, robust perennial, sparingly branched, 60-180 cm. 

 high; culms smooth and hard. Sheaths smooth, rather loose, 

 about the length of the internodes; ligule a fringe of hairs; blades 

 30-40 cm. long, about 10 mm. wide, flat or involute, scabrid above 

 and below, the apex long drawn out, Spike dense, usually 

 wholly exserted, cylindrical, 12-20 cm. long. Involucre a wide 

 row of erect spines and bristles placed around the margin of 

 the broad apex of a short pedicel. Spikelets single, as long as the 

 spines, ovate-lanceolate, 5 mm. long, first glume 9-nerved, second 

 5-nerved, third (palea) present; floral glume of the fertile floret 

 5-nerved, its palea 2-3-nerved. 



Mexico, Pringle 429, Palmer 765; Lower California, Palmer 

 327. 



"Wet land, Florida to Mexico. 



2. C. incertus M. A. Curt. Bost. Journ. Nat. Hist. 1 : 135 

 (1837). C. strictus Chapm. Coult. Bot. Gaz. 3: 20(1878). 



A smooth, nearly simple erect grass, 45-90 cm. high. Lower 

 sheaths longer than the internodes; ligule very short; blades con- 

 duplicate, 2-3 mm. wide. Spikes cylindrical, 5-8 cm. long, invo- 

 lucre at the base for 2-3 mm., the large spines 6-12 in number, 

 4-6 mm. long, ciliate. Spikelets in pairs, smooth, the sterile one 

 bearing 3 stamens. Sandy coast. 



Mississippi, Tracy; Florida, G. V. Nash 288. 



3. C. echinatus L. Sp. PI. 1050 (1753). 



An ascending annual, 30-60 cm. high. Sheaths loose, about 

 the length of the internodes; ligule ciliate ; blades flat, rough above, 

 often 25 cm. long, 10 mm. wide. Spike cylindrical, 5-12 cm, 

 long. Involucre about the length of the spikelets, many-lobed, 

 downy, lobes lanceolate-acuminate, spiny above, with a row of rigid 



