228 NORTH AMERICAN FLORA [Volume 17 



49. Panicum Havardii Vasey, Bull. Torrey Club 14: 95. 1887. 



Panicum virgatum macranthum Vasey, Bull. Torrey Club 13: 26. 1886. Not P. macranthum 

 Trin. 1826. 



Plants 1 meter tall or more, pale-green, glaucous, glabrous throughout; culms robust, 



¥ 



solitary, erect from creeping rootstocks, simple; leaf-sheaths longer than the internodes; ligule 

 dense, about 3 mm. long; blades erect or ascending, 25-40 cm. long, 5-10 mm. wide, broadest 

 at the base, tapering into long, involute-setaceous tips, sometimes pilose on the upper surface 

 at the base; panicles short-exserted, as much as 40 cm. long, half to three fourths as wide, loosely 

 flowered, the mostly verticillate branches ascending or finally spreading; spikelets 6-8 mm. 

 long, about 2 mm. wide, ovate, acuminate, strongly nerved; first glume clasping, half to two 

 thirds the length of the spikelet, acuminate; second glume slightly shorter than the sterile 

 lemma, both exceeding the fruit, 7-9-nerved; fruit 4.5-5 mm. long, about 1.8 mm. wide, narrow- 

 ly ovate, the margin of the lemma inrolled only at base. 



Type locality: Guadalupe Mountains, Texas. 



Distribution: Western Texas, southern New Mexico, and adjacent Mexico. 



Illustration: Contr. U. S. Nat. Herb. 15: /. 83. 



50. Panicum amarum Ell. Bot. S. C. & Ga. 1: 121. 1816. 



Panicum amarum minus Vasey & Scribn.; Vasey, Bull. U. S. Dep. Agr. Bot. 8: 38. 1889. 

 Panicum amaroides Scribn. & Merr.; Scribn. Circ. U. S. Dep. Agr. Agrost. 29: 5. 1901. 

 Chasea amara Nieuwl. Am. Midi. Nat. 2: 64. 1911. 



Plants glaucous and glabrous throughout; culms solitary from the nodes of extensively 

 creeping, horizontal rootstocks, simple or occasionally branching from the lower nodes, 30-100 

 cm. high; leaf-sheaths overlapping but commonly narrow and partially exposing the short, 

 very glaucous internodes; ligule dense and silky, about 3 mm. long; blades ascending or spread- 

 ing, thick, 10-30 cm. long, 5-12 mm. wide, broadest at the base, flat below, involute toward the 

 tip, the margins smooth; panicles short-exserted or included at base, one fourth to one third 

 the height of the plant, or sometimes more, not more than 3 cm. wide, mostly few-flowered, the 

 distant, appressed branches bearing scattered, short, appressed branchlets with approximate, 

 short-pediceled spikelets; spikelets 5-6.5 mm. long, about 2. mm. wide and as much as 3 mm. 

 thick, narrowly ovate, acuminate, strongly nerved; first glume clasping, two thirds to three 

 fourths the length of the spikelet, acuminate, 7-9-nerved, the midnerve usually scabrous toward 

 the apex; second glume slightly longer than the sterile lemma, both much exceeding the fruit, 

 9-nerved, the midnerves scabrous toward the apex; fruit 3.5 mm. long, about 1.5 mm. wide, 

 narrowly ovate. 



Type? locality: Probably South Carolina. 



Distribution: Sandy seashore, Connecticut to Georgia; Mississippi. 



Illustrations: Bull. U. S. Dep. Agr. Agrost. 14: /. 62; Circ. 29: /. 1; Contr. U. S. Nat. Herb. 

 15: /. 85; Francis, Book Grasses 65; Britt. & Brown, 111. FI./. 271; ed. 2./. 322. 



51. Panicum amarulum Hitchc. & Chase, Contr. U. S. Nat. Herb. 15: 



96. 1910. 



Plants glaucous, but less so than in P. amarum, glabrous throughout, cespitose in large 

 bunches sometimes as much as a meter across, 1-2 meters high; culms simple above the base, 

 stout, sometimes 1 cm. thick; leaf-sheaths mostly overlapping; ligule dense, about 3 mm. long; 

 blades erect or ascending, 20-50 cm. long, 5-12 mm. wide, broadest at the base, more or less 

 involute, pilose at the base on the upper surface; panicles finally exserted, one third the height 

 of the plant or more, 5-10 cm. wide, slightly nodding, compact, densely flowered, the long, 

 fascicled branches erect but more or less spreading at their tips, spikelet-bearing from the base ; 

 spikelets short-pediceled, 4.3-5.5 mm. long, 1.7-2 mm. wide, narrowly ovate, acuminate, 

 strongly nerved; first glume half to two thirds as long as the spikelet, acuminate, 5-7-nerved; 

 second glume slightly longer than the sterile lemma, both 7-9-nerved, pointed beyond the fruit; 

 fruit 3-3.5 mm. long, about 1.4 mm. wide, narrowly ovate, bluntly pointed. 



Type locality: Virginia Beach, Virginia. 



Distribution: Sandy sea shores, Virginia to Florida; Bahamas; Cuba. 



Illustrations: Bull. U. S. Dep. Agr. Agrost. 7: /. 55 (as P. amarum); Contr. U. S. Nat. Herb. 

 15: /. 87; Britt. & Brown, 111. Fl. /. 271 (as P. amarum); ed. 2./. 321. 



