FLOWERING PLANTS AND FERNS OF ARIZONA 143 



A smaller form with more crowded less acuminate spikelets, and 



fertile lemma as long as the second glume and sterile lemma, is var. 

 m inor (Vasey) Hitchc. This species is of some value as a forage plant. 



4. Eriochloa procera (Retz.) Hubbard, Kew Roy. Bot. Gard. Bui. Misc. 



Inform. 1930: 256. 1030. 



Agrostis proa ra Retz., Observ. Bot. 4 : 19. 1786. 



On campus of the University of Arizona, Tucson, Pima County 

 {Griffiths 1516). Cuba ; introduced from Asia. 



5. Eriochloa contracta Hitchc, Biol. Soc. Wash. Proc. 41: 163. 1928. 

 Sycamore Canyon near Ruby, Santa Cruz County, about 3,600 



feet {Kearney and Peebles 14484). Open ground, ditches, and wet 

 places, Kansas to Louisiana and Arizona, introduced in Missouri and 



Virginia. 



67. PASPALUM 



Perennials, with flat leaf blades and 2 to several spikelike racemes 

 paired or racemose on a common axis; spikelets solitary or paired in 

 two rows on one side of the rachis ; first glume usually wanting; second 

 glume and the sterile lemma equal, covering the fruit; fertile lemma 

 indurate, smooth, usually obtuse. 



These grasses are good forage plants. Dallisgrass (P. dilataium) 

 has been cultivated as a pasture grass in the southern United States 

 and elsewhere. Knotgrass (P. distichum) serves as a soil binder along 

 streams. 



Key to the species 



1. Racemes 2, paired; first glume often developed; plants often with extensively 



creeping stolons 1. P. distichum. 



1. Racemes 1 to 5, never paired; first glume obsolete; plants cespitose, without 

 stolons (2) . 

 2. Culms with terminal inflorescence only; spikelets 3 to 3.5 mm. long, the 



margins ciliate-fringed 2. P. dilatatum. 



2. Culms with terminal and axillary inflorescences: spikelets 2.1 to 2.2 mm. long, 

 glabrous or densely pubescent, the margins not fringed. 



3. P. STRAMIXEUM. 



1. Paspalum distichum L., Syst. Nat. ed. 10, 2: 855. 1759. 

 Yavapai, Maricopa, Cochise, Santa Cruz, and Pima Counties, at low 



altitudes, moist ground along streams and ditches, June to September. 

 New Jersey to Florida, west to California and northwest to Idaho and 

 Washington. 



2. Paspalum dilatatum Poir. in Lam., Encycl. 5: 35. 1S04. 



In the grass garden at Tucson, Pima County (Hitchcock 3474), per- 

 haps merely cultivated; introduced from South America. 



3. Paspalum stramineum Xash in Britton. Man. 74. 1901. 



Cochise and Santa Cruz Counties, about 4.000 feet, sandy open 

 ground, June to September. Indiana to Minnesota, south to Texas. 

 Arizona, and northwestern Mexico. 



68. PANICUM 



Annuals or perennials, with spikelets usually in open panicles; first 

 glume minute to more than half as long as the spikelet ; second glume 

 and the sterile lemma equal, usually covering the fruit, the sterile 



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