219 



the base ; stigmas obtuse or acnte. Disk annular, hypogynous. Capsule with from 1 to 4 

 cells; the valves fitting, at their edges, to the angles of a loose dissupiment, bearing the 

 seeds at its base ; sometimes valveless, or dehiscing transversely. Seeds with a small quan- 

 tity of muciliigiuous albumen; embryo curved; cotyledons shrivelled; radicle inferior. 



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

 cence. Leaves alternate, undivided, or lobed, seldom pinnatifid, with no stipulae. Inflo- 

 rescence axillary or terminal; peduncles 1- or many-flowered, the partial ones generally 

 with 2 bracteae. 



Affinities. The plaited corolla and climbing habit are the primd facie 

 marks of this order, which approaches Cordiaceas in its shrivelled cotyledons, 

 and through that tribe Boragineae, with which Falkia agrees in the deeply- 

 lobed ovarium. Nolan a, to be found in Solanese, would seem to establish 

 a relationship between Convolvulacese and that order also. Polemoniacese 

 'are known by their loculicidal dehiscence, which in Convolvulacese is always 

 opposite the dissepiments. Hydrolese are characterised by their indefinite 

 seeds, and taper embryo lying in the midst of fleshy albumen. 



Geography. Very abundant in all parts of the tropics, but rare in 

 cold climates, where a few only are found : they twine round other shrubs, 

 or creep among the weeds of the sea-shore. 



Properties. Their roots abound in an acrid milky juice, which is 

 strongly purgative; this quality depends upon a peculiar resin, which 

 is the active principle of the Jalap, the Scammony, and the others whose 

 roots possess similar qualities. Conv. Jalapa produces the real jalap, and 

 C. Scammonia the scammony; besides which, C. Turpethum, C. Mecho- 

 acanus, sepium, arvensis, Soldanella, macrorhizus, maritimus, macrocarpus, 

 and probably many others, may be used with nearly equal advantage. The 

 root of Convolvulus panduratus is used in the United States as jalap ; its 

 'operation is like that of rhubarb ; it is supposed to be also diuretic. Barton, 

 1. 252. The roots of Conv. floridus and scoparius, and Ipomoea Quamoclit, 

 are used as sternutatories ; those of C. Batatas and edulis are useful articles 

 of food : the former is the common sweet Potato of European gardens. The 

 Cuscutas are remarkable for becoming parasitical after having originally 

 germinated in the ground, from which they derive their nourishment until 

 they fix themselves firmly upon the plant that is finally to maintain them. 



Examples. Convolvulus, Evolvulus, Falkia. 



CC. POLEMONIACE^. The Greek Valerian Tribe. 



PoLEMONiA, Juss. Gen. 136. (1789) Polemovide^e, Dec. and Duby, 329. (1828).— 



PoLEMONiACE^, Lindl. Synops. 1G8. (1829) CoBiEACE^E, Don in Ed. Ph. 



Journ. 10. 111. (1824); Link Ilandb. 1. 822. (1829.) 



Diagnosis, Monopetalous dicotyledons, with regular flowers, a supe- 

 rior 3-celled ovarium, peltate or ascending ovules, and a pentandrous 5-parted 

 corolla, with imbricated aestivation. 



Anomalies. Cobaea has a climbing habit. 



Essential Character Calyx inferior, monosepalous, 5-parted, persistent, some- 

 times irregular. Corolla regular, 5-lobed. Stamens 5, inserted into the middle of the tube 

 of the corolla, and alternate with its segments. Ovarium superior, 3-celled, with a few or 

 many ovula ; style simple ; stigma trifid ; ovules ascending or peltate. Capsule 3-celled, 

 3-valved, few- or many-seeded, with a loculicidal or septicidal dehiscence; the valves sepa- 

 rating from the axis. Seeds angular or oval, or winged, often enveloped in mucus, ascend- 

 ing ; embryo straight in the axis of horny albumen ; radicle inferior ; cotyledons elliptical, 

 foliaceous. — Herbaceous plants, with opposite, or occasionally alternate, compound, or 

 simple leaves ; stem occasionally climbing. 



