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79. RIDDELLIA Nutt. 
Low and corymbosely branched woolly herbs, with alternate and 
spatulate or linear leaves, small heads. of yellow flowers (the ligules 
large and becoming pale or whitish and thin-papery with age), involucre 
of linear-oblong coriaceous woolly bracts (a few small scarious ones 
within), small flat naked receptacle, disk-corollas with glandular- 
bearded teeth, narrow terete obscurely striate or angled achenes, and 
pappus of 4 to 6 hyaline nerveless and pointless scales. 
1. R. tagetina Nutt. Loosely or somewhat villonsly woolly (sometimes glabrate 
in age), rather widely branched: radical and even lower cauline leaves often lacini- 
ate-pinnatifid: heads numerous, mostly cymosely clustered and short-peduncled: 
rays at maturity 12 mm. long: achenes and pappus glabrous (or the former with few 
and short scattered hairs): scales of the pappus oblong-lanceolate, entire, usually 
obtuse, one-half or three-fourths as long as disk-corolla.—Western Texas. 
2, R. arachnoidea Gray. Loosely woolly: stem and branches rather strict: 
foliage of the last: heads clustered, short-peduncled: rays at maturity only 6 mm. 
long: arachnoid hairs even longer than the somewhat turbinate achenes: scales of 
the pappus subulate-lanceolate, their margin and apex more or less deliquescent 
into.long and arachnoid hairs.—Southwestern Texas, beyond the Pecos. 
80. BAILEYA. Harvey & Gray. 
Soft and densely floccose-woolly annuals, with alternate leaves (the 
lower once or twice pinnatifid), terminal long pedunculate solitary heads 
of yellow flowers, large persistent rays (becoming scarious-papery) de- 
flexed in age, numerous thin-herbaceous linear involucral bracts very 
woolly on the back, flat or barely convex naked receptacle, disk-flowers 
with glandular-bearded teeth, oblong-linear or clay ..¢ somewhatangled 
striate achenes, and no pappus. 
1. B. multiradiata Harv. & Gray. Densely floccosely white-tomentose, at length 
much branched from the base and leafy: radical and lower leaves spatulate or 
broader, mostly laciniate-pinnatifid or sparingly bipinnatifid; uppermostsmall, spat-_ 
ulate-linear, entire: heads on slender often Jong peduncles: ligules 25 to50, 10 to 12 
mm. long: achenes oblong-prismatic and obscurely striate, broadest at the truncate 
apex, minutely scabrous.—Plains of western Texas. Var. NUDICAULIS Gray is more 
simple-stemmed or branched only from a stout base, with more divided leaves, elon- 
gated sometimes scapiform peduncles, and larger heads, 
81. LAPHAMIA Gray. 
Low suffruticulose perennials growing in crevices of rocks, mostly 
with petioled and dentate or laciniate small leaves (the upper alternate, 
rarely all opposite), small heads of yellow flowers either cymosely dis- 
posed or singly terminating the branches, involucre of equal narrow 
more or less overlapping bracts, female ray-flowers (with deciduous 
ligule) or none, 4-toothed disk-corollas, flat achenes with naked or not 
much ciliate margins, and pappus none or of 1 or 2 or sometimes about 
20 bristles. 
