Order Cv
COBEACEÆ.
A climbing genus with large purple flowers, recently separated from the Bignonias by Mr. Don. Nothing is known of its medicinal properties. 388 Cobæ'a Cav.
ORDER CVI.
POLEMONIACEÆ.
Herbaceous plants with showy blue, red, or white flowers, and often with pinnated leaves. They are natives of cool or mountainous parts in Europe and America. Nothing is known of their properties. 369 Phlox W. 70 Polemónium W.
ORDER CVII. 389 Cántua W.
CONVOLVULACEÆ. 390 Hoítzia Cav.
Nearly the whole of these are twining plants, with shewy flowers expanding beneath the influence of bright sunshine. A few are shrubs, but the greater part are herbaceous, and very many annual. They are frequently, also, weeds, which, from their creeping roots, are difficult to extirpate. All parts of the world produce them, from the cold regions of the north to the burning soil of the equator. Cúscuta is a singular parasite, wholly destitute of leaves. The root of many is filled with a milky acrid juice, which is very purgative. Scammony, jalap, and some other drugs, are the produce of Convolvulaceæ. The root of Convolvulus flóridus and scoparius, and Ipomæ a quamóclit, is stimulatory; that of Convolvulus batátas, which is the sweet potato of America and Southern Europe; and Convólvulus édulis are wholesome articles of food. Hydroleæ are little known, pretty, herbaceous plants, mostly with blue flowers, native both of cold and tropical countries; Diapénsia lappónica being an inhabitant of Lapland mountains, and Hydrólea spinósa of West Indian marshes. Their botanical characters are very nearly the same as those of Polemoniaceæ. The roots of Hydrólea spinósa are reputed bitter, and slightly purgative. Tribe 1. GENUINE. 383 Ipomæ'a R. Br. 384 Convólvulus W. 385 Argyréia Lour. 387 Calystégia R. Br. 602 Fálkia L. 695 Evólvulus L. 601 Hydrólea W.
Tribe 2. HYDROLEE. 358 Diapénsia W