630 



CONVOLVULACEyE. 



[Perigynous Exogens. 



Order CCXLI. CONVOLVULACE.E.— Bindweeds. 



Convolvuli, Juss. Gen. 133. (1789).— Convolvulacese, R. Brown, Prodr. 481. (1810); Until. Spnops. 

 167. (1829); Choisy in Mem. Soc. Phys. Genev. (1834); Alph. DC. Prodr. 9. 323. 



Diagnosis. — SJanal Exogens, with 5 free stamens, basal placenta, and leafy doubled up 



cotyledons. 



Herbaceous plants or shrubs, usually twining and milky, smooth, or with a simple 

 pubescence, sometimes erect bushes. Leaves alternate, undivided, or lobed, seldom 



Fig. ccccxxm 



pinnatifid, with no stipules. Inflorescence axillary or terminal ; peduncles 1- or many- 

 flowered, the partial ones generally with 2 bracts, which sometimes enlarge greatly 

 after flowering. In Mina the inflorescence is a one-sided and almost scorpioid raceme. 

 Calyx persistent, in 5 divisions, remarkably imbricated, as if in more whorls than 

 one, often very unequal. Corolla monopetalous, hypogynous, regular, deciduous ; the 

 limb 5-lobed, plaited ; the tube without scales. Stamens .5, inserted into the base of 

 the corolla, and alternate with its segments. Ovary simple, with 2 or 4 cells, seldom 

 with 1 ; sometimes in 2 or 4 distinct divisions ; few-seeded ; the ovules definite and 

 erect, when more than 1 collateral ; style 1, usually divided at the top, or as many as 

 the divisions of the ovary, and arising from their base ; stigmas obtuse or acute. Disk 

 annular, hypogynous. Capsule with from 1 to 4 cells, succulent or capsular ; the valves 

 fitting, at their edges, to the angles of a loose dissepiment, bearinn; the seeds at its base. 

 Seeds with a small quantity of mucilaginous albumen ; embryo curved ; cotyledons 

 leafy, shrivelled ; radicle inferior, next the hilum. 



The plaited corolla, imbricated calyx, and climbing habit, are the prima facie 

 marks of this Order, which approaches Sebestens in its shrivelled cotyledons, and 

 through that tribe Borageworts. Mina here, with its almost scorpioid inflorescence, 

 and Nolanads among the Echials, would seem to establish even a more direct 

 relationship between Bindweeds and that Order. Phloxworts are known by their 

 more copious albumen, straight embryo, and loculicidal dehiscence, which in Bind- 

 weeds is always opposite the dissepiments. Hydrophyls are characterised by their 

 parietal placentte, and taper embryo lying in the midst of fleshy albumen. Night- 

 shades have a dicarpellary fruit, with axile placenta?, and numerous seeds ; otherwise, 

 they are sometimes very like the shrubby erect species of Bindweed. The Order has 

 been re-arranged by Choisy in De Candolle's Prodromus, but that author has been 

 sharply criticised by Bentham {London Journal of Botany, May, 1845, p. 244), and 

 with justice. 



Fig. CCCCXXIII.— Ipomcea Batatoides. 1. the pistil and annular disk; 2. a transverse section of 

 the ovary ; 3. a capsule of Convolvulus tricolor ; 4. a vertical section of the seed of that species. 



