GRASSES OF IOWA. 241 



S. DIARRHENA. 



Diarrhena Reauv. Agros. 142. 1812. Raf. Jour. Phys. 89: 104. 1819. 

 Endlicher Gen. PL 102. Bentham & Hooker. Gen. PL 3: 1190. Hackel 

 in Engle & PrantL Nat. Pflanz. Fara. II. 2: 70. 



Festuca Michx. Fl. Bor. Am. 1: 67. pi. 10. 1803. 



Korycarpus Scribner. Bull. U. S. Dept. Agrl. 



Spikelets several flowered, smooth and shining; one or two of the 

 uppermost flowers sterile. Empty glumes ovate, much shorter than the 

 flowers, coriaceous; the lower much smaller: flowering glume ovate, 

 convex on the back, rigidly coriaceous, its three nerves terminating in a 

 strong and abrupt, cuspidate or awl-shaped tip. Squamulae ovate, ciliate, 

 Stamen.- 2. Grain very large, obliquely ovoid, obtusely pointed, rather 

 longer than the glume, the cartilaginous, shining pericarp not adherent 

 to the seed. A nearly smooth perennial, with running rootstocks, pro- 

 ducing simple culms, 2 to 3 feet (4-10 dm.) high, with long, linear- 

 lanceolate, flat leaves tow arils the base, naked above, bearing a few short- 

 pedicelled spikelets 2 to 3 lines ( 4-b mm.) long, in a very simple panicle. 

 (Name composed of two Greek words for two and man, from the two 

 stamens.) 



Bentham cc Hooker recognize two species; the same number is 

 given by Hackel. The Diarrhena Americana occurs in eastern North 

 America, while the Diarrhena Japonica is native to Japan. 



1. DIARRHENA AMERICANA. 



Diarrhena Americana Beauv. Agrost. 142. 1812. Watson and Coulter. 

 Gray. Man. Bot. 662. pi. 10. 1890. 16 ed.) Scribner. Grasses of Tenn. 

 Bull. Univ. Tenn. Agr. Exp. Sta. 7: 101. /. 131 . 1894. 



Korycarpus diandrus (Michx.) Kuntze. Beal. Grasses of N, A. 2: 511. 

 f. 102. 1S96. Nash in Britton and Brown. 111. Fl. 1: 196. f. 449. 1896. 

 Scribner. Bu.l. U. S. Dept. Agr. Div. Agros. 7: 268. f. 362. 1900. (3d ed ) 



Korycarpus arundinaceus Zea. Acr. Matrit. 1806. 



Festuca diandra Michx. Fl. Bor. Am. 1: 67. pi. 10. 1803. 



DESCRIPTION. 



Twin Grass. An erect perennial, 2 to 3 feet (5-7 dm.) high, with 

 long, narrow-lanceolate, nearly erect leaves, and a few flowered, simple 

 panicle, 4 to 10 inches (9-22 cm.) long. Sheaths scabrous or some 

 times pubescent above; ligule very short, rigid; leaf-blade 6 to 24 

 inches (12-48 cm.) long, 5 to 12 lines (10-24 mm.) wide, tapering 

 a narrow base, very long acuminate-pointed. Panicle-branches erect 

 Spikelets 3 to 5 lines (6- 10 mm.) long, three to six-flowered, the upper 

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