HITCHCOCK AND CHASE — NORTH AMERICAN PANICUM. 



85 



Panicles diffuse, or only slightly contracted; plants some- 

 times of salt marshes but not littoral. 

 Spikelets 6 to 8 mm. long; culms solitary, with a 



creeping base 45. P. havardii. 



Spikelets less than 5 mm. long (in exceptional speci- 

 mens 6 mm. long); culms erect, producing 

 numerous scaly rootstocks. 

 Panicles open, loosely-flowered; spikelets 3.5 to 

 5 mm. long, beaked; first glume two-thirds 

 the length of the spikelet or more, acumi- 

 nate-pointed 44. P. virgatum. 



Panicles somewhat contracted; spikelets not over 

 3.2 mm. long, not beaked; first glume about 

 half the length of the spikelet, not acumi- 

 nate 44a 



P." virgatum cub- 



ense. 



42. Panicum repens L. 



Panicum repens L. Sp. PI. ed. 2. 87. 1762. "Habitat in Hispania? inde missnm a 

 Claud. Alstraemer." The type specimen is in the Linnsean Herbarium. 



Panicum notatum Retz. Obs. Bot. 4:18.1786. "In Sumatra * * * D. 

 Wennerberg." The specimen from Sumatra in the Willdenow Herbarium labeled 

 Panicum notatum, though probably not the type, agrees with the description and 

 may be regarded as an authentic specimen. 



Panicum arenarium Brot. Fl. Lusit. 1: 82. 1804. "Hab. in arenosis subhumidis; 

 occurrit in Algarbiis. ' ' We have not seen the type specimen, but the ample descrip- 

 tion and the plate given later by Brotero o clearly identify this species with P. repens L. 



Panicum littorale Mohr; Vasey, Bot. Gaz. 4 : 106. 1879. "Mobile, Alabama," sent 

 by "Mr. Chas. Mohr." The type specimen, in the National Herbarium, was collected 

 by Dr. Mohr, July 4, 1877. 



A few other names based on Old World plants, the type specimens of which we 

 have not seen, are referred to P. repens as synonyms 

 by various authors. 



DESCRIPTION. 



Culms rigid, 30 to 80 cm. high, erect or ascending 

 from the nodes of strong, horizontal, often extensively 

 creeping rootstocks, simple, clothed at the base with 

 bladeless, overlapping sheaths; upper leaves numer- 

 ous, the sheaths usually overlapping, rather loose, 

 more or less pilose, especially along the margin, or 

 sometimes glabrous; ligules about 1 mm. long; blades 

 4 to 15 cm. long, 2 to 5 mm. wide, or those of sterile 

 shoots sometimes longer and wider, firm, stiffly ascending or spreading, often conspic- 

 uously distichous, flat or folded, long-pilose at the base on the upper surface, other- 

 wise sparsely pilose to glabrous on both surfaces; panicles rather short-exserted, 

 stramineous, 7 to 12 cm. long, one-third to two-thirds as wide, the somewhat distant 

 branches stiffly ascending, rarely spreading, usually naked at the base, bearing short, 

 appressed branchlets with short-pediceled, approximate spikelets toward the ends; 

 spikelets 2.2 to 2.5 mm. long, 1 to 1.1 mm. wide, ovate, abruptly pointed; first glume 



Fig. 75.— P. repens. From type 

 specimens of P. littorale Mohr. 



a Brot. Phytog. Lusit. 1 : 15. pi. 6. 1816. 



