SCKBCIOKIDE*] 



SYNGENESIA 485 



towers rather large, terminal; peduncles stout, angular, hirsutely pubescent ; 

 1 Aets of the involucre lanceolate, hispid and ciliate ; rays numerous, yellow ; 

 finrels of the disk numerous, greenish-yellow. Akenes subcompressed, cuneatc* 

 blong, somewhat Wangled, smooth ; pappus 2 subulate chaffy scales. Receptacle 

 haffu the chaff oblong, acuminate, with an acute tooth on each side, near the apex, 

 pubescent at summit. 

 Hab. Gardens, and lots .-frequent. F\. August— Sept. Fr. October. 



Obs. This is °fl en cultivated for the firm fleshy tubers, at the root,— which art 

 wckled arul used as a condiment* The plant is apt to become troublesome in gar- 

 dens. The H. annuus, or common Sun-flower, is very common about our gardens ; 

 —but it is neither naturalized, nor cultivated for any useful purpose, here,— though 

 the seeds are said to afford a valuable oil. Some 18 or 20 additional species have 

 been enumerated in the U. Slates,— and there are probably some y in the South 

 and West, which are not yet described. Indeed the whole of our North American 

 tpecies require a careful revision, by some competent hand. 



§ 5. Biobntide^. Heads either hetcrogamous, with neutral florets in a singU 

 series in the circumference, or homogamous, and then the akenes awned ; akenes 

 without coating, beaked, never with a crown-form pappus. 



387. BIDENS. L. Mat. Gen. 691. 

 [Latin, bi-dens, having two teeth ; alluding to the awns of the akenes.] 



Involucre many-leaved, the leaflets in a double series, unequal, the 

 outer ones spreading. Rays often wanting. Jlkenes obcompressed, 

 not winged ; pappus 2 to 5 retrorsely hispid persistent aivns. Re- 

 ceptacle mostly flat, with chaffy bracts. 



1, B. cHRTSANTHE>roiT)ES, JStx. Leaves oblong-lanceolate, tapering 

 at each end, serrate, sessile, and connate at base ; heads radiate, some- 

 what nodding; rays 2 or 3 times as long as the iuvolucre. JBeck, 

 Bot. p. 207. 



Chht8awthemum-ltke Bideks. Vulgo— Beggar-ticks. 



Root annual 1 Stem 1 to 2 feet high, erect, or declining, often angular, striate, 

 smooth, branching, the branches opposite and axillary. Z^at>«s3to6incheslong, 

 and half an inch to an inch and half wide, opposite, lanceolate, acuminate, den- 

 tate-serrate, smooth, somewhat scabrous on the margin, narrowed at base, sessile 

 and connate. Heads of flowers rather large, solitary, terminating the branches, 

 erect, or often somewhat nodding; involucre double,— the outer leaflets about 8, 

 foliaceous, spreading, linear-lanceolate, smooth, ciliate-scrrulatc on the margin, 

 unequal, the largest sometimes nearly as long as the rays,— the inner leaflets 

 membranaceous, elliptic, or ovate-oblong, striate, yellow on the margin, nearly 

 •qual, about as long as the florets of the disk; rays bright yellow, numerous, 

 lance-oblong, about twice as long as the inner leaflets of the involucre ; florets of 

 the disk funnelform, greenish-yellow. Akenes compressed, oblong-cuneate, re- 

 trorsely aculeate on the margins, striate-ribbed, and somewhat keeled on the 

 flatted sides ; pappus usually consisting of 4 (2, Mx.) retrorsely hispid awns about 

 as long as the disk-florets. Receptacle slightly convex, chaffy, the chaff spatulate- 

 linear, scarious, with 3 central longitudinal striae, yellowish at summit, rather 

 obtuse, remotely denticulate on the margin. 



Bub. Low grounds; along swampy rivulets: frequent. Fl. Aug— Sept, Fr. Oct*. 



