332 COMPOSITE. Bahia. 



Amauna, Benth, Bot. Sulpli., of Lower California, insufficiently known, is per- 

 haps an epappose Bahia. 



§ 1. Suffruticose {B. amhrosioides, Lag., of Chili) or herbaceous from a per- 

 ennial sometimes lignescent root : paleai of the pappus 4 to 8, obovate or spatu- 

 late, with rounded or truncate scarious summit, and thickened base or imperfect 

 costa : leaves dissected or cleft, the lower opposite. 



B. oppositifolia, Nutt A span or two high, fastigiately branched and many-stemmed, 

 herbaueous to tlie base, very leafy up to the short-ped uncled lieads, cinereous with fine close 

 pubescence : leaves mostly opposite, petioled, palnuitely or pedately 3-5-parted into linear 

 divisions little broader than the margined petiole : head 4 or 5 lines high : bracts of the 

 involucre oblong or oval, comparatively close (the outer obscurely carinate-oue-nerved) : 

 rays 5 or 6, oval, hardly surpassing the disk-flowers : akenes slender, glandular : pappus half 

 the length of the corolla-tube, the palea^ narrowly obovate, with strongly opaque centre eva- 

 nescent near the summit. — Torr. & Gray, Fl. ii. 376; Gray, PI. Fendl. 99. Trichophi/llum 

 opposit I folium, Nutt. Gen. ii. 167. — Sterile hills and j)lains, Nebraska to Colorado and the 

 borders of New Mexico. 



B. absinthifolia, Bexth. About a foot high from an herbaceous root or barely suffru- 

 tescent base, diffusely branched, tomentnlose-cauesccnt, and with sparsely corymbose-panicu- 

 late heads on slender peduncles : leaves opposite and the upper alternate, pedately or 

 sometimes pinnately 3-5-parted into narrowly linear or lanceolate divisions and lobes : 

 involucre more lax ; its bracts oblong-spatulate or lanceolate with narrowed base : i-ays 9 to 

 12, lanceolate-oblong, much exceeding the disk: akenes slender, pubescent : pappus nearly 

 equalling the proper corolla-tnbe, its paleas more dilated and broadly thin-scarious above. — 

 PI. Hartw. 18. — Arizona, near Tucson, Palmer, Lemmon. (Forms almost as slender and 

 narrow-leaved as the plant of Northern Mexico.) 



Var. dealbata, Gray. Perhaps more lignescent at base, more whitened with fine 

 pannose tomeutum: leaves less divided, commonly only 3-cleft into lanceolate or linear- 

 oblong lobes, or some lower ones oblong-lanceolate and entire. — PI. Wright, i. 121 ; Proc. 

 Am. Acad. xix. 27. B. dealbata, Gray, PI. Fendl. 99. — Dry plains, AV. Texas to Arizona. 

 (Adj. Mex.) 



§ 2. Herbaceous from a perennial caudex : leaves all alternate and entire, 

 coriaceous: paleae of the papjDUS about 10, linear-lanceolate, and with a distinct 

 excurrent or percurrent costa. — § PlatyscltkuJiria, Gray. 



B. nudicaiilis, Gray. Cinereous-puberulent and glabrate, upper part of the scapiform 

 stem and involucre minutely glandular, a span or two higii : leaves nearly all radical, oval or 

 spatulate-oblong (an inch or more long), taj)cring into a slender petiole : Iieads solitary or 

 few and somewhat corymbosely paniculate, nearly half-inch high : involucre hemispherical, 

 of about 10 oblong bracts: rays 6 to 9, oblong : pappus fully half the length of the cuneate- 

 linear sparsely hairy akene ; tlie thin margins of the paletc of the pappus erose, and the 

 short-excurrent awn barbellate-hispidulous. — Proc. Am. Acad. xix. 27. — Schluhria (Platy- 

 schkuhria) intecjrijolla, Gray in Am. Nat. viii. 213, & Proc. Am. Acad. ix. 198, exd. var. — 

 Wind River Mountains, N. W. Wyoming, Parry. 



B. oblongifolia, Gray, 1. c. Smaller : stems sparsely leafy almost to the 3-cephalous 

 naked inflorescence : leaves narrowly oblong : head only 4 lines high, narrow : pale* of the 

 pajjpus firmer, smoother, and with entire edges, little shorter than tlie glabrate akene. — 

 Schkiihria integrijblia, var. oblotyjifolla, Gray in Am. Nat. 1. c. — On the San Juan and Rio 

 Colorado, near their junction, S. E. Utah or adjacent Colorado, Newberry, Brandegee. 



§ 3. Annuals, with once or twice palmately or pedately divided leaves : akenes 

 mostly hirsute along the slender attenuate base, at least on the angles. — Achyro- 

 papjyus, IIBK. 



* Loaves mainly opposite, at lea.st all the lower ones, their divisions narrowly linear: pappus of 

 broad and very obtuse pale;e, scarious above, callous-thickened and ojiaqiie at base, as hi § 1 : 

 ray-flowers occasional!}' wauting. — Gray, Proc. Am. Acad. xix. 27. Aclii/rojKipjms, HBK., DC. 



