GENERA OF GRASSES OF THE UNITED STATES. 189 



West Indies. The second and third are described as new ; the others are based 

 on Linnsean species, the first on Agrostis cruciata, the fourth "on Andropogon 

 polydactylon, and the fifth on Agrostis radiata. The first species is selected as 

 the type. 



Eustachys Desv., Nouv. Bull. Soc. Philom. Paris 2: 188. 1810. One species 

 is described, E. petraeus, based oil Chloris petraea Swartz. Eustachys, recog- 

 nized by some American botanists as distinct, forms a section of the genus 

 Chloris and includes four species, C. petraea, C. glauca (Chapm.) Vasey, C. 

 floridana (Chapm.) Vasey, and C. neglecta Nash. The group differs from 

 Euchloris in having the lemmas short-awned or mucronate, brown, and rather 

 firm in texture. 



Chlorostis Raf., Princip. Fondament. Somiologie 26, 29. 1814. Proposed 

 change of name for Chloris Swartz, because of Chlora L. ( : an animal) . 



Several species are found on the plains of Texas, where they form 

 an unimportant part of the forage for grazing animals. Chloris 

 verticittata Nutt. and its allies are known as windmill grasses. The 

 mature inflorescence, consisting of several slender, divergent spikes, 

 breaks away from the plant and rolls before the wind as a tumble- 

 weed. In the Southwestern States is found C. virgata Swartz (C. 

 elegans H. B. K.) (fig. 112), a tuftecl annual, 1 to 2 feet high, with 

 several pale or purplish, erect, feathery spikes 1 to 2 inches long. This 

 species invades cultivated fields and sometimes becomes a rather 

 common weed, especially in alfalfa fields. 



One species, C. gayana Kunth, a native of South Africa, is culti- 

 vated to a limited extent as a forage grass. This species, called 

 Rhodes grass, has been shown to have value as a meadow grass in 

 the Southwestern States. In the Hawaiian Islands it is used on some 

 of the ranches in the drier regions. Rhodes grass is a perennial, 2 

 to 3 feet high, producing long, stout, creeping, propagating stems or 

 stolons and bearing at the summit of the flowering stems a close fan- 

 shaped cluster of numerous spikes 2 to 4 inches long. 



For a revision of the species of Eustachys and Chloris found in the 

 United States, see Nash, Bull. Torrey Club 25 : 432-450. 1898. 



94. TRICHLORIS Fourn. 



Spikelets 1 to few flowered, nearly sessile, in two rows along one 

 side of a continuous slender rachis, the rachilla disarticulating above 

 the glumes and prolonged behind the uppermost perfect floret, bear- 

 ing a reduced, usually awned floret; glumes unequal, acuminate, or 

 short-awned, the body shorter than the lower lemma; lemmas nar- 

 row, 3-nerved, the marginal nerves sometimes pubescent, these and 

 the midnerve extending into awns, the central long and slender, the 

 lateral often much shorter. 



Erect, slender, tufted perennials, with flat blades and numerous 

 erect or ascending spikes, aggregate but scarcely digitate at the 

 summit of the culms. Species two or three, in the dry regions of 

 Texas and Mexico and also in Argentina. 



