332 COMPOSITZ ADENOCAULON 
DIMERESIA ~ 
glabrous, 4-sided. Roadsides and wast places: introduced from Europe. 
Subtribe iv Adenocaulee Gray Syn. Fl. i, pt. 2, 59. 
Heads heterogamous, discoid; both pistillate and hermaphro- 
dite flowers with tubular more or less ampliate 4-5-toothed 
or -lobed corolla: involucre not scarious: receptacle naked: 
achenes elongated, striate or nerved: pappus none. 
33 ADENOCAULON Hook. Bot. Mise. i, 119, t. 15. 
Perennial herbs with slender stems.alternate and dilated leaves 
on long margined petioles, and very small heads of whitish flow- 
ers. Heads several to many-flowered ; the marginal ones pistil- 
late only; the more numerous central ones hermaphrodite-sterile. 
Involucre of few thin herbaceous bracts. Receptacle flat, naked. 
Corollas all somewhat alike; of the sterile flowers broadly fun- 
nelform and deeply 4-5-cleft; of the fertile ones less ampliate, 
either regularly 4-lobed, or bilabiate with the outer lip 3-lobed. 
Style of the sterile flowers undivided; of the fertile ones with 
short and broad stigmatic branches. Anthers sagittate, the au- 
ricles minutely but evidently caudate, connate. Achenes obovate- 
oblong or clavate, very obtuse, very much exceeding the involu- 
cre, the upper part beset with stout stipitate glands. 
A. bicolor Hook. 1.c. Stems 1-3 feet high, leafy helow: leaves dilated- 
cordate, 1-3 inches long by nearly as broad, coarsely sinuate-dentate or 
repand or slightly lobed, early glabrate and green above, white with thin 
cottony wool beneath: bracts of the involucre 4-5, in a single series, ovate, 
reflexed in fruit: fertile corollas regularly 4-lobed : achenes club-shaped, 2-3 
lines long. Common in forests and woods, Alaska to California and east 
to Lake Superior. 
Subtribe v. Dimeresex. Heads homogamous, flowers all herma- 
ghrodite and fertile, Corollas tubular and. regular, 5-toothed. 
34 DIMERESIA Gray Syn. FI. i, pt. 2, Supp. 448. 
Low annuals with opposite leaves and 2-flowered heads in 
dense terminal glomerules. Heads discoid, homogamous, the 
flowers hermaphrodite and fertile. Invyolucre of 2 herbaceous 
oblong concave bracts, a little united at base, each subtending 
and almost enclosing a flower. Corolla tubular, regular, 5-tooth- 
ed. Anthers sagittate at base, the narrow auricles but little ex- 
tended. Style-branches narrowly linear, obtuse, not appendaged, 
the bordering stigmatic lines extending to and around the naked 
apex. Achenes clavate-pyriform, glabrous, many-striate, with 
small epigynous areola, bearing a pappus of stout plumose bristles 
in a single series which are united at base in a ring and early 
deciduous together. 
D. Howellii Gray 1. c. 449. Stems stoutish, minutely floccose-woolly, 
simple or branched, 6-18 lines long, from a long annual taproot: leaves ob- 
ovate or oval, including the broad petiole 10-14 lines long, thinly white- 
woolly beneath, soon glabrate and green above: heads numerous, subses- 
sile, in dense terminal glomerules: corollas purplish or flesh-color: pappus 
