Convolvulus. XCViil. CO^'VOLVULACEiE. 441 



Order XCVII. DTAPENSIACE^. 



Under shrubs, prostmtc, with omwilcd, hciilli like h-iivcs uinl solitary, termiiml flowers. 



Ca/. —St'puls 5, much imliricjitcd, surroiiiidetl at base with imbricutcd scaJus. 



Cor.— Petals 5, imilnl. ri iridar, imhricati-d in a'stivatioii. 



Sta. 5, eciual. tlie tilanit riis pctidoid and iiiHcrted on llie corolla tube. 



Anth. 'i-Cfllud. Iransvcr.scly valvrd. 



Ova. 3-celled, iVfe. Stijlrs unittd info 1. Stifrma 3 lobi-d. 



Fr-.— Capsule 3-vulved, locuJicidal. tifeiln mtmy , .siniiii, ulbuminous. 



Genus l,or2 according to many authors, species 2, natives of the north of Europe and the northern 

 parts of Nortli America. 



DIAPENSIA. 

 Calyx r)-parted, calyculatc 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 

 uiiderskrubs. 



§ J . Anthers awnless. 



1. D. Lapponica. Northerti Diapensia. 



Ccespito.se; lis. dense, spatulate, fleshy, evergreen, obtuse and entire; Jls. 

 pedunculated. — 1\. 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, clasping 

 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. Pyxidanthera. Anthers with the lower valves beaked. 



2. D. BARBur,.\TA. Ell. (Pvxidanthera barbulata. Michx. D. cuneifolia. 

 Ph.) — Branches short, ascending; lis. lance-cuneiform, acute, pubescent 



at base ; Jls. terminal, sessile ; lon-er valve of the «??/AeT beaked or awned at ba.se. 

 — A pro.strate, 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" by i — 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. 



Order XCYIII. C ON VOLVULACE^.— Bindweeds. 



Herbs or shrubs, with a milky juice, mostly twining, sometimes erect. 



Lvs. alternate, without stipules, sometimes wholly wantins;. Fls. showy. 



Ca;.— Sepals 5, much imbricated, u.sually united at b;ise, persistent. 



Cor. regular, limb 5 lobed or entire, plaited and twisted in a^stivation. 



Sta. 5, uiserted into the base of the corolla and alternate with its lobes. 



Ova. 2— 4-celled, free. Snjles 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. Jalap of the shops 



is the product of the root of Exogonium purga of Mexico, and other species. Seanwiony of Convolvulus 



Scammonia, native of Levant. The dra.>tic qualities of both depend upon the presence of a peculiar 



resin. The sioeet potato, a valuable article of Ibod, is the product of C. Batatas, native at the South. 



Conspectus of the Genera. 



4 Style simple Convolvulus. I 



^Stamens included. (Styles 3 or 2 Stijlisoia. 3 



^ Calyx naked. (Stamens exserted. Corolla scarlet. . . . Quamoclit. 2 



Ueafy, green. < Calyx enclo.sed in two large, leaf-like bracts Calystegia. 4 



Plants i leafless, parasitic, orange-colored Cuscuta. 5 



Suborder 1.— C ONVOIiVULE^. 



Embryo with cotyledons. Carpels united. Fruit capsular, dehiscent. 

 1. COxWOLVlJLUS. 



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 fuuuel-form, limb 5-plaited ; sta. shorter than the 

 limb, rarely a little longer ; ova. 2 — 4-celled, cells 1 — 2-ovuled ; sty. 



