276 MONOPETALOrS OEDEES. 
or shrubs, often with milky juice. Learns alternate. Caly^ 
persistent, in 5 divisions, much imbricated. Corolla regular, 
deciduous ; the linnh 5-lobed, plaited. Stamens 5, inserted into 
the tube of the corolla, and alternate with its segments. Ovary 
free, 2-4-celled ; styles united, or more or less distinct. Fruit 
succulent or capsular. 
Seeds with a small quan- 
tity of mucilaginous albu- 
men ; embryo curved ; co- 
tyledons foliaceous. 
a. Properties: the roots con- 
tain an acrid milky juice, which 
is strongly purgative ; the C. ba- 
tatas, or sweet potato, is an im- 
portant article of food. 
Genera. — Evolvulus, Ipomaea 
Convolvulus. 
Fig. 199, a, Ipom^ hatatoides ; 
h, the pistil and annular disk ; 
c, capsule of C. tricolor ; d, a ver- 
tical section of its seed. 
Sub-order Dichonde^. — Carpels distinct. Dichondra. 
Sub-order Cuscutin^. — Embryo filiform, coiled spirally in 
fleshy albumen, destitute of cotyledons. Parasitic, leafless, 
twining herbs destitute of green color. Cuscuta. 
494. PoLEMONiACE^, tJie Phlox Tribe. — Herbaceous plants ; 
stem occasionally climbing. Leaves opposite or alternate. Calyx 
5-parted, persistent, sometimes irregular. Corolla regular, 
5-lobed, aestivation convolute. Stamens 5, inserted on the co- 
rolla alternate with its segments. Ovary free, 3-celled ; ovules 
few or many ; style simple ; stigma trifid. Fruit a 3-celled, 
3-valved capsule. Seeds angular, oval, or winged ; embryo 
straight, in fleshy or horny albumen. 
Genera. — Phlox, Polemonium. 
495. DiAPENSiACEjE. — Prostrate, suffruticose plants. Leases 
evergreen, densely imbricated. Flowers solitary, terminal. Sep- 
als 5, much imbricated, scarcely distinguishable from the 
bracts which are closely imbricated around it. Corolla regular, 
sestivation imbricated. Stamens 5, equal ; filaments petaloid, 
arising from the margin of the sinuses of the corolla ; anthers 
transversely 2-valved. Ovary 3-celled. Fruit capsular. Seeds 
many ; embryo in fleshy albumen. 
Genera. — Diapensia, Pyxidanthera. 
496. SoLANACE^, the Potato Tribe. — Herbs or shrubs. 
Leaves alternate, the floral ones sometimes double, and 
crowded. Lnflorescence variable. Calyx 5, seldom 4-];)arted, 
persistent, inferior. Corolla plaited, or valvate in sestiyatii^n ; 
