CONVOLVULACEJS. (CONVOLVULUS FAMILY). 



Fig. 256. 



557 



Fig. 256, (a) Seed of Convolvulus, (b) Longitudinal section of same, showing the 

 crumpled cotyledon, (c) Another section of the same, showing the curved, crumpled embryo. 

 (d) A face view of the cotyledon and radicle in the act of germination, (c) Half-side view 

 of both cotyledons ** and radicle -f in germination. 



1. IPOM^ A. Calyx naked at base. Stigma capitate, usually 2-lobed. 



2. CALYSTEGIA. Calyx bracted at base. Stigmas 2, ovate or oblong. 



3. CONVOLVULUS. Calyx naked or 2-bracteoled at base. Stigmas 2, linear-cylindrical. 



Tribe II. CRESSES. Low, leafy shrubs, with linear, 2-plaited cotyledons, and 

 imbricated aestivation. 



4. CRESS A, Corolla 5-parted to middle. Leaves minute. Styles 2. 



Tribe III. CUSCUTEiE. Leafless, parasitic twiners, without cotyledons, and 

 with spiral embryo. Calyx 4-5-cleft. 



Fig. 357. 



Fig. 257. (a) Stem of a Cuscuta, twining and parasitic on the stem of another plant, 

 with two clusters of flowers. (6) The coiled embryo, (c) The same uncoiling iteelf in 

 germination. 

 5, CUSCUTA. Calyx and corolla 5-cleft, the latter often urn-shaped in fruit. 



1. IPOM^A, L. Morning-Glory. 



Calyx 5-sepaled. Corolla broad-funnel-shaped, showy, 5-lobed or 

 repand, 5-plaited. Style 1, stigma capitate, generally 2-lobed. Ovary 

 2-3-4-celled, with 2 seeds in each cell. Capsule (in ours) 2-celled — 

 Twining, glabrous herbs or shrubs, 



1. I. littorali§, L. 1^ .3 to .5, trailing on the ground, rooting 

 by under surface of branches. Leaves fleshy, ,01 to .03 long, oblong, 

 Jiddle-shaped or three-lohed^ lateral lobes often bifid, terminal oblong-ellip- 

 tical^ all obtuse. Peduncles of 1-2 upper axils 1-flowered, shorter than 

 leaves; sepals elliptical, obtuse, mucronate; corolla .04 long, cream- 

 colored, 4-6 times as long as calyx ; lobes of stigma rounded ; capsule 

 .014 broad — Autumn — Sands along coast. 



