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79, Riddellia. Involucre cylindraceous-campanulate, of 4 to 10 coriaceous woolly 
bracts: ligules as broad as long, abruptly contracted at base into a short tube: pap- 
pus of 4 to 6 hyaline pointless scales. 
80. Baileya. Involucre hemispherical. of numerous thin-herbaceous bracts very 
woolly on the back: ligules narrower, tapering into a narrow but not tubular base: 
pappus none, 
***Involucre of equal and narrow erect bracts, in 1 or 2 series: ray-flowers female 
or none, the ligule deciduous: disk-corollas 4-toothed: achenes flat, with only 
marginal callous nerves, usually much ciliate: plants not floccose-tomentose, 
and with no oil-glands. 
81. Laphamia. Margin of achenes naked or not much ciliate: pappus none, or of 
1 or 2, or sometimes about 20 bristles: suffruticose perennials. 
82. Perityle. Achenes at maturity with or without cartilaginous-margin, usually 
strongly ciliate: pappus a scaly or cupulate crown, and commonly a slender awn from 
one or both angles: mostly annuals. 
**** Involucre hardly at all imbricated, its bracts when broad nearly equal or in a 
single series: ligules not persistent: disk-flowers numerous, 5- (rarely 4-) 
lobed: achenes few-nerved or angled, or more numerously striate-angled only 
when turbinate or pyriform: no oil-glands. 
+ Receptacle flat or convex: achenes from linear to obpyramidal, rarely 5-angled, 
occasionally with intermediate nerves: flowers all fertile. 
++ Involucre many-flowered; its bracts wholly herbaceous and plane: corolla-lobes 
or teeth short, 
83. Bahia. Involucre lax or open in fruit: achenes narrow, quadrangular: pap- 
pus (rarely wanting) of several scarious scales. 
++ ++ Involucre 3 to 9-flowered; its bracts broad and with roundish more or less scari- 
ous-petaloid summit, carinate-concave: corollas 5-toothed: herbage minutely 
punctate, 
84. Schkuhria. Heads effusely paniculate: involucre of 4 or 5 erect bracts: 
female flowers only 1 or 2, with a short or obsolete ligule: achenes obpyramidal- 
tetragonal: pappus of 8 scarious palew: leaves or their divisions filiform. 
++++ ++ Involucre many-flowered; its bracts mostly appressed, with scarious-mem- 
branaceous and usually colored tips and sometimes margins: ray-flowers 
none (except in no, 87): disk-corollas deeply 5-cleft: leaves alternate. 
85. Hymenothrix. Pappus about the length of the achene, of 12 to 20 narrow 
lanceolate hyaline scales traversed by a strong rib which is excurrent into a sca- 
brous awn: disk-corollas with narrow tube and lobes. 
86. Hymenopappus. Pappus of 10 to 20 thin-scarious and mostly hyaline obtuse 
scales, sometimes very short and small or obsolete: disk-corollas with narrow tubes, 
dilated throat, and ovate reflexed or spreading lobes, 
87. Plorestina. VPappus of 6 to 8 obovate pointless scales, hyaline-scarious froma 
‘allous-thickened base or axis: disk-corollas widely dilated above the short narrow 
tube, deeply 5-cleft into oblong spreading lobes. 
84. Polypteris. Pappus of 6 to 12 equal scales, with a strong pereurrent costa, 
otherwise hyaline-scarious, rarely wanting: disk-corollas with filiform tube ab- 
ruptiy dilated into a 5-parted limb with long linear lobes. 
+ + Receptacle convex to oblong: achenes short, obpyramidal or turbinate, 5 to 10- 
ribbed or angled, mostly silky-villous or hirsute: disk-flowers all fertile, the 
corolla 4 or 5-toothed: leaves alternate,in many minutely impressed-punctate, 
++ Receptacle destitute of awn-like fimbrillx. 
= Involucre not spreading or reflexed. 
89. Actinella. Heads radiate: receptacle from conical to convex: rays fertile: 
pappus of 5 to 12 thin and mostly hyaline scales, with more or less manifest costa or 
