206 CONTRIBUTIONS FROM THE NATIONAL HERBAKI I'M. 



with flat blades 5 to lo mm. wide, and large panicles L5 to 25 cm. long, the branches 



ascending, about 1 cm. long, or even as much as 2 cm. The commoner form <>\ '\ ■ 

 and northern Mexico is less robust, the blades narrower, 3 to 4 mm. wide, often 

 folded, the panicles more compactly flowered and spikelike. There are so many 

 intermediate specimens that it seems impracticable to draw specific lines between 

 the forms. 



Certain specimens approach C. rarifiora in habit (such as, Texas: Bush L252, Rose 

 18051, Hitchcock 5178, Chandler 7085), but differ in the glabrous (but scabrous blades, 

 pubescent but not pilose rachis, and pale spikelets (in C. rariflora the green nerves are 

 prominent) . 



The following specimens have pubescent sheaths and "blades: Texas: Hitchcock 

 5337, Ball 1527, Groth 123, Jermy 38. Sonora: Rose 13004. San Luis Porosf: 

 Hitchcock 5729. Nuevo Leon: Hitchcock 5542, Pringle 1968. ' The first glume is 

 5-nerved in Rose 10116. 



A few specimens from Lower California have the aspect of typical Chaetochloa 

 macrostachya but have slender spikelike panicles and glabrous sheath margins. The 

 specimens, which are in a fragmentary condition, were described by Scribner and 

 Merrill as Chaetochloa rigida, but the differences mentioned do not appear sufficient 

 to indicate a distinct species. The specimens are: Palmer 125, 857; Brandegee in 1890; 

 Purpus 227. 



Chaetochloa macrostachya is closely related to C. selosa, but differs in having a more 

 compact and much less tapering panicle. In C. setosa the panicle is attenuate at the 

 summit. 



DISTRIBUTION. 



Open dry ground and dry woods, southwestern United States to Oaxaca. 



Texas: Estelline, Reverchon 4262. Kingsville, Piper in 1906; Tracy 8882. Kinney 

 County, Hill 83; Mearns 1216. San Antonio, Hitchcock 5132. 5162, 5178 jpgmfl 

 1179, 1252; Tweedy in 1880. El Paso, Hitchcock ^37 J 7825, 13320, V > 



5S94, 5903; Stearns 179; Rose 17886. Chisos Mountains, Bailey 392. Corpus 

 Chnsti, Hitchcock 5363; Heller 1480. New Braunfels, Hitchcock 5226. Laredo, 

 HUchcock 5508; Mackenzie 107; Rose 18051; Havard in 1884. Maravillas, Havardm 

 1883. Kent, Tracy & Earle 378. Del Rio, Plank 87; Hitchcock 13631. Big 

 Spring, Hitchcock 13376, 13397. Robstown, nitchcock 5388. Sarita. Hitchcock 

 5478. Rio Hondo, Chandler 7085. Bexar County, Jermy 38, 21 1. Bracken, Groth 

 123. Alpine, Hitchcock 13605. Uvalde, Ball 1527; Reverchon 1097 in 1885. 

 Baylor County, Reverchon 1097 in 1879. Valverde County, Nealley 115. Western 

 Texas, Wright 799, 800; Havard in 1881. Olmito, Tracy 8907. Bears Mountain, 

 Jermy 783. 



Colorado: Canon City, Eastwood in 1892; Jones 780; Shear 979. 



New Mexico: Mangas Canyon, Smith in 1896. Mangas Springs, Metcalft lot. Dona 

 Ana Mountains, Standley in 1906. Organ Mountains, Hitchcock 3796. Mesilla 

 Valley, Standley 407; Hitchcock 3818; Wooton 60. Las Cruces. Vasey in 1881; 

 Wooton 1081. Deming, Hitchcock 3757. Rincon, JWs 4163. Grant County. 

 Rusby 455. Roswell, Griffiths 5738. Cimarron Canyon, Griffiths 5554. Jarilla 

 Junction, Cockerell 19. Aden, TJoo/on in 1906. Albuquerque, Tracy 85 in 1887. 

 WhiteWater, Mearns 2313. Carlsbad, Hitchcock 13489. TortugasMountain,S/arcd- 

 Zet/ 6418. Black Range, Metcalfe 1147. Organ Mountains. Fase^ in 1881; FTootoTJ 

 438. Without locality, Wright 2094. 



Arizona: Tucson, To ttmey 805 and in 1894; Griffiths 1511, 3349, 3352: Hitchcock 

 3491: Prmj/Ze in 1884. Patagonia, Hitchcock 3659, 3660, 3678. Santa Rita 



1 This was referred to Chaetochloa setosa by Scribner and is the original of the 

 figure so named (U. S. Dept. Agr. Div. Agrost. Bull. 21: 39./. :-',. L900 



