FLOWERING PLANTS AND FERNS OF ARIZONA 983 



6. Bahia woodhousei A. Gray, Amer. Acad. Arts and Sci. Proc. 19: 28. 



1883. 



Achyropappus woodhousei A. Gray, ibid. 6: 546. 1865. 

 Picradeniopsis woodhousei Rydb., Torrey Bot. Club Bui. 37: 

 333. 1910. 



Woodruff, Navajo County {Ward in 1901), Red Butte to Rattle- 

 snake Tanks, Coconino County (Leiberg 5915), about 5,000 feet, 

 June to September. Northwestern Texas, Colorado, and northern 

 Arizona. 



*7. Bahia oppositifolia (Nutt.) DC, Prodr. 5: 656. 1836. 



TrichophyUum oppositvfolium Nutt., Gen. PI. 2: 167. 1818. 

 Picradeniopsis oppositifolia Rydb. ex Britton, Manual 1008. 

 1901. 



Plains and hillsides, North Dakota to Montana, south to western 

 Texas and New Mexico (reported from Arizona), June to September. 



The plant contains a cyanogenic principle but is rarely if ever eaten 

 by livestock in sufficient quantity to cause prussic-acid poisoning. 



8. Bahia absinthifolia Benth., PL Hartw. 18. 1839. 



Cochise County near the Mexican boundary (Mearns 756, etc.), 

 mesas and slopes, April to October. Southern Texas and southeastern 

 Arizona to central Mexico. 



Much more common in Arizona than the typical form is var. deal- 

 bata A. Gray, which differs in having the leaves merely 3-cleft into 

 lanceolate lobes, or entire (in the typical form the leaves pedately 

 parted into 3 or 5 narrowly linear or lance-linear divisions, these 

 usually again few-lobed). The variety occurs in Graham, Maricopa, 

 Pinal, Cochise, Santa Cruz, and Pima Counties, 2,400 to 5,500 feet, 

 and ranges to western Texas and Chihuahua. It is particularly 

 abundant on shallow caliche soils around Tucson. 



97. TRICHOPTILIUM 



Low, diffusely branched, floccose-woolly, winter annual; leaves 

 mostly alternate, oblong to lanceolate, sharply dentate; heads terminal, 

 solitary, slender-peduncled, discoid, yellow; achenes turbinate, 5- 

 nerved, hairy; pappus of 5 paleae, these dissected into numerous 

 bristles. 



1. Trichoptilium incisum A. Gray in Torr., U. S. and Mex. Bound. 

 Bot. 97. 1859. 



Psathyrotes incisa A. Gray, Amer. Acad. Arts and Sci. Mem. 

 ser. 2, 5: 322. 1854. 



Mohave, Maricopa, and Yuma Counties, up to 2,000 feet, sandy or 

 gravelly mesas and slopes, February to May (sometimes autumn). 

 Southern Nevada, western Arizona, southeastern California, and 

 Baja California. 



98. ACTINEA 



Annual or perennial herbs; leaves alternate, entire to pinnatifid; 

 heads radiate, yellow; involucre in 2 or more series, the phyllaries 

 often rigid, the outer ones sometimes united at base; pappus of 

 5 to 12 paleae. 



