144 GAMOPETALOUS EXOGENS 



pressed, or slender and 4-sided ; pappus 2 to 4 or 5 rigid persistent 

 retrorsely-hispid awns. Receptacle flattish ; chaff deciduous. Mostly 

 annuals : leaves opposite, penninerved ; flowers generally yellow. 



f Akenes^of, with ciliate margins, not tapering at summit. 

 * Rays usually wanting. 



1. 11. frondosa, L. Leaves odd-pinnately divided in fives and 

 threes, the leaflets lanceolate, serrate; akenes 2-awned, ciliate with 

 erect hairs. 

 FRONDOSE, OR FOLIACEOUS BIDENS. Bur-Marigold. 



Stem 2 to 4 or 5 feet high, angular, branched, sparsely pilose, often dark purple. 

 Leaflets 2 to 4 or 5 inches long, with short margined petioles ; common petiole 1 to 3 

 inches long, somewhat margined. Heads of flowers rather small, on long slender 

 naked axillary branches ; involucre double, the outer scales 8 to 10 or 12, folia- 

 oeous, unequal, much longer than the head, ciliate near the base ; rays none. 

 Akenes obovate-cuneate, antrorsely ciliate ; awns longer than the florets. 

 Hob. Gardens; fence-rows, &c. : common. Fl. Aug. Fr. Octo. 



Obs. A homely, troublesome weed, in gardens, and lots. The 

 adhesive akenes, of all the species, are a well-known annoyance. 



!2. B. COnnata, Muhl. Leaves lanceolate, serrate, tapering at 



base to margined subconnate petioles ; akenes 3- or 4-awned, re- 



trorsely hispid-ciliate. 



B. petiolata. Nutt. & FL Cestr. ed. V.p. 486. 



CONNATE BIDENS. 



fitfin 1 to 2 or 3 feet high, striate, branched, smooth, often purple. Leaves 2 to 

 5 or 6 inches long, with a long entire acumination, smooth. Heads of flowers 

 middle-sized ; involucre double, the outer scales about 5, foliaceous, much longer 

 than the head; rays generally wanting. Akenes striate, retrorsely hispid on the 

 margins ; pappus 3 or 4 retrorsely hispid awns, the 2 middle ones shorter, and of 

 these the inner one often entirely wanting. 

 Hob. Low, swampy grounds; ditches, <fec.: frequent. FL Sept. Fr. Octo. 



* * Rays numerous and conspicuous. 



3, B. dirysanthemoides, MX. Leaves oblong-lanceolate, 

 tapering at each end, dentate-serrate, sessile and connate ; akenes 

 2- to 4-awned, retrorsely aculeate-ciliate. 

 CHRYSANTHEMUM-LIKE BIDENS. Beggar-ticks. 



t^tem 1 to 2 feet high, erect, or reclining at base, often angular, smooth, branch- 

 ed, the branches opposite and axillary. Leaves 3 to 6 inches long, smooth, rough- 

 ish on the margin. Heads of flowers rather large, solitary on the branches, often 

 woinewhat nodding ; involucre double, the outer scales about 8, foliaceous, spread- 

 ing, the largest ones nearly as long as the bright yellow rays. Akenes somewhat 

 keeled on the flatted sides ; pappus usually 4 (sometimes 2, or 3) rctrorsely hispid 

 awns about as long as the disk florets. 

 Hob. Low grounds; along swampy rivulets: frequent. Fl Aug. Fr. Octo. 



f f Akenes ^sided, long and slender, tapering at summit. 



4. B. blpinnata, L. Leaves bipinnately dissected, petiolate ; 

 rays about 3, small; akenes 3- or 4-awned, subliuear, sulcate, 

 smooth ish. 



BJPLNNATE BIDENS. Spanish Needles. 

 Stem 2 to 4 feet high, 4-angled, smooth, blanched. Leaves 2 to 4 or 5 .Inches 



