398 SYNGENESIA— POLYGAMIA-^QU. Bidens. 



Comynon CaL erect, of several oblong, nearly equal, parallel 

 scales, concave, or channelled, at the back. Cor. com- 

 pound, of several, parallel, level-topped, perfect, tubu- 

 lar, regular and equal Jlorets; their limb ovate, with 5 

 marginal, spreading segments. Filam. from the tube, 

 capillary, very short. Anth. in a cylindrical tube, 

 slightly prominent. Germ, oblong, compressed, with 2 

 or more bristly upright points, about equal to the tube 

 of the floret, on its outside. Sti/le thread-shaped, within 

 the tube. Stigmas oblong, spreading beyond the an- 

 thers. Seed-vessel none but the unaltered close calyx. 

 Seed compressed, abrupt, angular, rough at the edges, 

 and beaked with 2 or more bristles, rough with minute 

 reflexed prickles. Recept. flat, beset with upright, chaff'y, 

 oblong, deciduous scales as tall as the florets. 



Most species are occasionally liable to acquire marginal ra- 

 diant fertile florets^ destitute of stamens^ which consti- 

 tutes the character of Coreopsis. Such a change is nearly 

 analogous to becoming double in the generality o^Jlowers^ 

 and is not, as some have thought, a more perfect state 

 of the compound tribe, but rather the contrary. 



Herbaceous, mostly annual, upright plants, with opposite, 

 simple or compound, lobed or serrated leaves. FL stalk- 

 ed, somewhat corymbose, erect or drooping, terminal or 

 axillary, the base of the cali/j: encompassed with a circu- 

 lar row of spreading leafy hracteas ; disk yellow; the ra- 

 ^\a\\X.Jiorets^ when they occur, are in some species white. 

 Willdenow considers the bracteas as an outer calyx^ in 

 which he may perhaps be correct. 



1. ^.tripartita. Three-lobed Bur-marigold. 



Leaves in three segments. Bracteas unequal. Bristles of 

 the seeds two or three, erect. 



B. tripartita. Linn. Sp.PlAUD. Willd.v.3A7\5. FlBr.SoS. 



Engl. Bot. v.\Q. t.W 13. Curt. Lond.fasc. 4. t. 57. Hook. Scot. 



238. 

 B. n. 121. Hall Hist. V. 1.51. 

 Verbesina, seu Cannabina aquatica, flore minus pulchro,^ elatior 



et magis frequens. Rail Syn. 187. Bauh. Hist. v. 2. 1073. 

 Chrysanthemum cannabinum bidens, folio quinquepartito, sive 



vulgare. Moris, v. 3. 17. sect. 6, t.5.f. 20. 

 Eupatorium cannabinum foemina. Ger. Em. 711./. Lob. Ic. 529,/j 



bad. 

 Hepatorium aquatile. Dod. Pempt. 595./. 

 Hydropiper alterum. Dakch. Hist. ] 039. f. 



