COMPOSITE. 71 



Subtribe II. RIDDELLIEJE. Involucre of narrow equal erect bracts. Ligules persistent 

 and becoming papery on the usually striate-nerved akenes. Herbage moie, or less 

 white- woolly : no oil-glands. 



* Pappus paleaceous : rays very broad, few. 



131. RIDDELLIA. Heads with 3 or 4 ray- and 5 to 12 disk-flowers, all fertile. Involucre 

 cylindraceous-campanulate, of 4 to 10 linear-oblong coriaceous \voollv bracts, and a few 

 smaller scarious ones within, sometimes au additional narrow outer one. Receptacle small, 

 flat. Ligules as broad as long, abruptly contracted at base into a short tube, truncate and 

 2-3-lobed, 5-7-nerved, the nerves uniting in pairs within the lobes. Disk-corollas elongated- 

 cylindraceous, with very short proper tube, and short externally glandular-bearded teeth. 

 Style-branches truncate-capitate. Akenes narrow, terete, obscurely striatc or angled. Pap- 

 pus of 4 to 6 hyaline nerveless and pointless paleje. 



-* * Pappus none : rays several or numerous : disk-flowers numerous. 



132. BAILEYA. Involucre hemispherical, of numerous thin-herbaceous linear bracts in 

 2 or 3 series, very woolly on the back. Receptacle flat or barely convex. Kay-flowers 

 5 to 50 ; the ligules from round-oval to oblong-cuueate, 3-toothed at apex, 7-nerved, taper- 

 ing into a narrow but not tubular base, becoming scarious-papery but thin, persistent on the 

 truncate summit of the akene. Disk-flowers fertile; their corollas tubular-funnelform above 

 the short proper tube, 5-toothed ; the teeth glandular-bearded. Style-branches short, with 

 truncate-capitate tips. Akeues oblong-linear or clavate, somewhat angled, pluricostate or 

 striat^; the truncate apex obscurely toothed by extension of the ribs, or in the ray callous- 

 thickened. 



133. WHITNEYA. Involucre campanulate, of 9 or 12 oblong or broadly lanceolate 

 equal thin-herbaceous bracts, nearly in a single series, in fruit somewhat cyiubit'orm-eari- 

 nate near the base, not villous. Receptacle narrow-conical, villuus. Hay-flowers 7 to 9 ; 

 ligule elongated-oblong, minutely 3-toothed at apex, 10-lG-nerved (the nerves also prominent 

 on the short tube), becoming thin-papery, persistent. Disk-flowers numerous, infertile, the 

 tubular-funnelform obtusely 5-toothed corollas persistent on the sterile akcues : style-branches 

 linear, pubescent externally, with rather obtuse tips. Eay-akenes only maturing, oblong, 

 slightly obcompressed, obtuse at both euds, lightly nerved. 



Subtribe III. PERITYLE^. Involucre of equal and narrow erect bracts, in only one or 

 two series. Ray-flowers female or none ; the ligule deciduous : disk-cornllas narrow, 

 4-toothed. Akenes flat, with only marginal callous nerves, usually much ciliate. 

 Style-branches and their appendages slender. Receptacle Hat or convex Plants not 

 floccose-tomentose, and with no oil-glands, (ttuhca, 154, might be sought li 

 Eatondla, 137, and Crockeria, 137 a , also have flat and ciliate akciius willi strong mar- 

 ginal nerves.) 



134. LAPHAMIA. Head several- to many-flowered. Bracts of the hemispherical invo- 

 lucre distinct, more or less overlapping. Style-tips setaceous subulate, hirsute. 



akenes naked or not much ciliate. Pappus none, or of one or two, or sometimes 

 bristles. Suffruticulose perennials, or herbaceous from a thick woody I 

 flowered. 



1 35 PERIT YLE Head many-flowered. Involucre of preceding, or the bracts more can. 

 ' nate-concave and partly embracing outer akenes. Style-branches with either B 



or obtuse) or slender hirsute tips. Akenes at maturity cartilaginous-margined usually 

 strongly ciliate. Pappus a squamellate or cupulate crown, and commonly . 

 from one or both angles. Mostly annuals, white- or yellow-flowered 



136 PERICOME Head many-flowered, homogamous. Involucre a strictly si i 

 of numerous narrow bracts, which are lightly connate by their edges mto a , 

 cup. Disk-corollas sleuder, with viscous-glandular tube nearly the lengl h of 1 he cj 

 throat, from which the anthers are much exserted. Style-tips filiform, rather , 

 Akeues strongly villous-ciliate. Pappus a squamellate lacerate-ciliate crown, and 



a pair of short awns, one from each angle of the akene. Perennial, yellow-f) 

 long-acuminate leaves. 



