CoNVOLVULUS. XCVIII. CONVOLVULACESR. 441 
Orver XCVII. DIAPENSIACE®. 
ndershrubs, prostrate, with crowded, heath-like leaves and solitary, terminal flowers. 
Cal.—Sepals 5, much imbricated, surrounded at base with imbricated scales. 
Cor.—Petals 5, united, regular, imbricated in estivation. 
Sta. 5, equal, the filaments petaloid and inserted on the corolla tube. 
Anih. 2-celled, transversely valved. 
Ova. 3-celled, free. Styles united into1. Stigma 3-lobed. 
Fr.—Capsule 3-valved, loculicidal. Seeds many, small, albuminous. 
Genus 1, or 2 according to many authors, species 2, natives of the north of Europe and the northern 
parts of North America. 
DIAPENSIA. 
Calyx 5-parted, calyculate with 3 bracts at base; corolla hypocra- 
teriform, limb 5-cleft, flat ; stamens 5, from the summit of the tube ; 
stigmas 3; capsule 3-celled, 3-valved, many-seeded.— Low, evergreen 
undershrubs. 
§ 1. Anthers awnless. 
1. D. Lapponica. Northern Diapensia. 
Ceespitose; dvs. dense, spatulate, fleshy, evergreen, obtuse and entire; fis. 
pedunculated.—?| A little, leafy plant, 2—3’ high, growing on the summits of 
the White Mts. in N. Hampshire, forming dense tufts among the rocks. Leaves 
crowded, pale beneath, fleshy, 5—8” by 1’ with a revolute margin, c.asping 
base, and broadly obtuse point. Flowers on short, terminal, solitary peduncles, 
which are an inch long in fruit. Calyx of 5, obtuse leaves, longer than the 
leafy bracts at its base. Corolla white, with 5, flat segments. July. 
§ 2. PyxipanTHeRA. Anthers with the lower valves beaked. 
2. D. BarBuLATa. Ell. (Pyxidanthera barbulata. Michz. D. cuneifolia. 
Ph.)—Branches short, ascending; Jvs. lance-cuneiform, acute, pubescent 
at base; fs. terminal, sessile ; lower valve of the anther beaked or awned at base. 
—A prostrate, creeping plant, abundant in pine barrens, N. J. to Car., forming 
dense beds. It has also been found by Dr. Peck on the White Mts. ( fide Torr. 
Stems 3—6/ long, subhispid. Leaves 1—2” by3}—1”. Flowers white, 3” diam. 
Sepals denticulate, as long as the corolla tube. May, Jn.—The beak of the 
anther appears to be quite variable, sometimes reduced to an acute point. 
Orver XCVIIL CONVOLVULACEA.—Buinpweeps. 
Herbs or shrubs, with a milky juice, mostly twining, sometimes erect. 
Lvs. alternate, without stipules, sometimes wholly wanting. Fils. showy. 
Cal.—Sepals 5, much imbricated, usually united at base, persistent. 
Cor. re , limb 5-lobed or entire, plaited and twisted in estivation. 
Sta. 5, inserted into the base of the corolla and alternate with its lobes. 
Ova. 2—4-celled, free. Styles united into 1. : 
Fr.—Capsule 2—4-celled, valves with septifragal dehiscence. ; : 
Sds. few, large, with thin mucilaginous albumen. Cotyledons foliaceous, or wanting. 
Genera 43, species 660, very abundant in tropical climates, rare in cold. 
Properties.—The roots abound in an acrid, milky juice which is strongly purgative. Jaloe of the shops 
is the product of the root of Exogonium purga of Mexico, and other species. Scammony of Convolvulus 
Scammonia, native of Levant. The drastic qualities of both depend upon the presence of a peculiar 
resin. The sweet potato, a valuable article of food, is the product of C. Batatas, native at the South. 
Conspectus of the Genera. 
‘ ¢eei simple... . . . Convolvulus.1 
Stamens included. ? Styles 3or2. . : : . Stylisma. 3 
Calyx naked. Stamens exserted. Corollascarlet. . . . Quamoclit. 2 
leafy, green. ¢ Calyx enclosed in two large, leaf-like bracts. . . . . «. Calystegia. 
Plants i parasitic, orange-colored. ear aes)? So Ougseuatee: 5 
SusorpDERI1—CONVOLVULEX. 
Embryo with cotyledons. Carpels united. Fruit capsular, dehiscent. 
1 CONVOLVULUS. 
Lat. convolvere, to entwine ; from the habit of most of the plants. 
Calyx 5-parted, naked or with 2 small bracts near the base; cor. 
campanulate, or funnel-form, limb 5-plaited; sta. shorter than the 
limb, rarely a little longer; ova. 2—4-celled, cells 1—-ovuled ; sty, 
