62 University of California Publications in Botany. [VOL. 3 



Freely branching leafy shrub, 6 dm. or less high: stems 

 densely white-tomentose, the foliage very minutely glandular, the 

 involucres nearly glabrous: leaves linear, acute, 2 to 5 cm. long, 

 2 or 3 mm. wide, 1-nerved : heads few, in a narrow terminal leafy 

 raceme, about 9-flowered: involucre narrowly campanulate; 

 bracts about 12, loosely imbricated in very indistinct vertical 

 ranks, thin-chartaceous, lanceolate, acuminate, the principal ones 

 11 or 12 mm. long, several of the outermost ones with elongated 

 green tips overtopping the proper involucre and resembling the 

 uppermost leaves: throat and teeth of the corolla sparsely 

 arachnoid-pubescent: style-branches filiform, long-exserted : 

 achenes sericeous-pubescent. 



Mainly of the Rocky Mts., but this description from specimens 

 gathered at 2100 m. altitude in the arid Transition Zone of 

 Alamo Mt., eastern Ventura Co. (Hall, no. 6701). 



16. ISOCOMA Nutt. 



Somewhat woody plants with elongated rigid stems and thick- 

 ish closely sessile leaves. Herbage never resinous-punctate. 

 Heads rayless, collected into glomerules which are either terminal 

 on short lateral branchlets or disposed in a terminal cymose 

 cluster. Involucral bracts coriaceous, closely imbricated, the tips 

 herbaceous but appressed. Flowers permanently yellow. Corolla- 

 tube slender, the throat ventricose or obliquely dilated, its seg- 

 ments erect or more or less connivent about the style. Style- 

 appendages subulate-lanceolate or broader. Achenes longitudi- 

 nally striate or ribbed, silky-pubescent or hirsute. Pappus of 

 numerous sordid bristles, the innermost longest and often dis- 

 tinctly flattened. 



1. I. veneta vernonioides (Nutt.) Jepson, Fl. W. Mid. Calif. 

 560 (1901). I. vernonioides Nutt., Trans. Am. Philos. Soc. ser. 

 2. vii. 320 (1841). Bigelovia Menziesii Gray, Proc. Am. Acad. 

 viii. 638 (1873). Isocoma microdonta, latifolia, villosa, sedoides, 

 & decumbens Greene, Leaflets i. 171-2 (1906). 



Plant 4 to 12 dm. high, half-woody at the branched base 

 above which the stems are commonly simple up to the cymose or 

 paniculate inflorescence: herbage from minutely scabrous to 



