GENERA OF GRASSES OF THE UNITED STATES. 189 
-West Indies. The second and third are described as new; the others are based 
on Linnzan 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 on Chloris petraew Swartz. Hustachys, 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 
Buchloris in having the lemmas short-awned or mucronate, brown, and rather 
firm in texture. 
Chilorostis 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 
verticillata 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 tufted annual, 1 to 2 feet high, with 
seyeral 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. 
