COMPOSITiE. 71 



Subtribe II. Riddellie.^. Involucre of narrow equal erect bracts. Ligules persistent 

 and becoming papery on the usually striate-nerved akenes. Herbage more 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 

 cyhndraceous-caiiipanuhite, of 4 to 10 Hucar-obloug coriaceous woolly bracts, and a few 

 smaller scarious ones within, sometimes an additional narrow outer one. Keceptacle 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 clongated- 

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

 Style-brauclies truncate-capitate. Akenes narrow, terete, obscurely striate or angled. Pap- 

 pus of 4 to G hyaline nerveless and jjoiutless paleaj. 



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



133. BAILEYA. Involucre hemispherical, of numerous thiu-herbaceous linear bracts in 

 2 or 3 scries, very woolly on the back. Rece^jtacle flat or barely convex. Pay-flowers 

 5 to 50 ; the ligules from round-oval to oblong-cuneate, 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 tuliular-funnelform above 

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

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

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

 tliickcned. 



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

 equal thin-herbaceous bracts, nearly in a single series, in fruit somewhat c_ynibiform-cari- 

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

 ligule elongated-oblong, minutely 3-toothed at apex, 10-16-nerved (the nerves also prominent 

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

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

 linear, ])ubesceut externally, with rather obtuse tips. Ray-akeues only maturing, oblong, 

 slightly obcompressed, obtuse at both ends, lightly nerved. 



Subtribe III. Perityle.e. Involucre of eqiial and narrow erect bracts, in only one or 

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

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

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

 floccose-tomentose, and with no oil-glands. (Ilulsea, 154, might be sought here. 

 Eatondla, 137, and Orockeria, 137^, also have flat and ciliate akenes with 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. Margin of 

 akenes naked or not much ciliate. Pappus none, or of one or two, or sometimes about 20 

 bristles. Suffruticulose perennials, or herbaceous from a thick woody base, mostly yellow- 

 flowered. 



135. PERITYLE. Head many-flowered. Involucre of preceding, or the bracts more cari- 

 nate-concave and partly embracing outer akenes. Style-branches with either short (acute 

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

 strongly ciliate. Pappus a s(iuamellate or cupulate crown, and commonly a slender awn 

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



136. PERICOME. Head many-flowered, homogamous. Involucre a strictly single series 

 of numercjus narrow bracts, which are lightly connate by their edges into a campanulate 

 cup. Disk-corollas slender, with viscous-glandular tube nearly the length of the cylindrical 

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

 Akenes strongly villou.s-ciliate. Paj)pus a S(iuamellate laccrate-ciliate crown, and sometimes 

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

 long-acuminate leaves. 



