344 ; COMPOSIT A - COREOPSI8 
BIDENS 
leaves usually all opposite, the lower bipinnately parted or divided, with 
linear lobes; the upper trifoliolate, with entire linear leaflets. or the upper- 
most linear and entire: heads numerous, in open cymes: bracts of the in- 
volucre more or less scarious-margined, the outer lanceolate to subulate, 
about a line long; the inner broad-ovate and 3-4 lines long: rays 8-10 lines 
long by half as broad, yellow with brown base, obtusely 3-lobed at the 
summit; disk-flowers dark purplish-brown: achenes elliptical, distinctly 
winged, crowned with 2 short subulate often deciduous teeth. Damp 
meadows along rivers, Oregon to Brit. Columbia. 
45 BIDENS Tourn. L. Gen. n. 932. 
Annual or perennial herbs with opposite lower leaves and mostly 
large heads of yellow flowers, Invyolucre campanulate or hemi- 
spheric, its bracts in 2 series, distinct or united at base, the outer 
often foliaceous and much larger thanthe inner. Receptacle flat 
or nearly so, chaffy, the chaff subtending the disk-flowers Rays 
when present, neutral, mostly entire. Disk-flowers perfect, fertile, 
with tubular. 5-toothed corollas. Anthers entire or minutely 
sagittate at base. Style-branches with short or subulate tips. 
Achenes flat, quadrangular or nearly terete, cuneate, oblong or 
linear. Pappus of 2-6 teeth or subulate barbed or hispid awns. 
B. frondosa L. Sp. 852. Glabrous or somewhat hairy annual: stems 
erect, 2-8 feet high, branching: leaves pinnately 3-5-divided into lanceolate 
or broader sharply serrate and pinnately veiny commonly petiolulate leaf- 
lets, or the uppermost undivided: heads usually numerous, peduncled, 
about 6 lines high: involucre campanulate becoming hemispheric, its 
otiter bracts more or less foliaceous, often much exceeding the ovate-lance- 
olate scarious-margined inner ones: rays none, or rudimentary and incon- 
spicuous: achenes flat, oval or obovate, ciliate, with 2 slender downwardly 
barbed awns. Moist places mostly along streams, Qregon to Brit. Colum- 
bia and across the Continent. | 
B. cernua L. Sp. 832. Annual: stems glabrous or setulose-hispid, 1-3 
feet high : leaves oblong-lanceolate, coarsely and irregularly sharply ser- 
rate, 3-6 inches long, sessile and commonly somewhat connate-perfoliate 
at base: heads numerous, 6-8 lines broad, nodding after or during flower- 
ing: rays 6-12, 3-8 lines long, or more: involucre depressed-hemispheric. 
its outer bracts commonly ciliate, often large and foliaceous and much 
exceeding the broad yellowish-margined membranaceous inner ones: 
achenes flat, cuneiform, usually 4-awned the margins and awns retrorsely 
barbed. In wet places, California to Brit. Colunbia and across the Con’t. 
B. Beckii Torr. in Spreng. Neue Entdeck. ii, 135. Aquatic perennial; 
submersed stems much elongated in deep water, simple or little branched: 
submersed leaves sessile, 1-2 inches long, repeatedly divided into numer- 
ous capillary segments; emersed ones few, sessile, opposite or sometimes 
-in 3’s, lanceolate or oblong, acute, serrate or laciniate, 6-18.lines long: 
heads solitary or few, short-peduncled: involucre hemispheric, its bracts 
oval or oblong, obtusish, glabrous, the outer somewhat shorter than the 
inner: rays 6-10, obovate or oblong, obtuse, golden yellow: achenes nearly 
terete, truncate at both ends, half-inch long: pappus of 3-6 rigid persistent 
awns which are smooth below, the upper part downwardly barbed. In 
ponds and slow flowing streames, Canada to New Jersey and Missouri: re- 
ported from Green Lake King Co. Washington by Mr. C. V .Piper, perhaps 
introduced. 
Subtribe v, Madiee DC, Ray-flowers ligulate and fertile (rarely 
