CoNVOLVL-LUs. XCVIII. CON VOLVULACEiE. 441 



Order XCVII. DIAPENSIACE^. 



Undenhrubs pro8tm<i, with crowded, heath-like leaves and solitary, terminal flowera 



CaL— sepals 5, much imbricated, surrounded at base with imbricated scales 



^or.— Petals 5, united, regular, imbricated in estivation. 



Sta. 5, equal, the filaments petaloid and inserted on the corolla tube 



Anth. 2-celled, transversely valved. 



Ova. 3-celled, fi-ee. Snjles united into 1. Stigma 3-lobed. 



Fr.— Capsule 3-valved, loculicidal. Seeds many, small, albuminous. 



„»9»®""*-^ J' ^u^.^^'^'^'''^'"^ ^^^ ™^"y authors, species 2, natives of the north of Europe and the northern 

 parts 01 JNorth 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 

 underskrubs. 



§ 1. Anthers awnless. 



1. D. Lapponica. Northern Diapensia. 



Caespitose; Ivs. dense, spatulate, fleshy, evergreen, obtuse and entire- ds 

 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, solitarv peduncles 

 which are an inch long in fruit. Cal)^x of 5, obtuse leaves, longer than the 

 leafy bracts at its base. Corolla white, with 5, flat segments. July. 



§ 2. Pyxidanthera. Aiithers with the lower valves beaked. 



2. D. BARBULATA. Ell. (Pyxidauthcra barbulata. Michx. D. cuneifolia. 

 P/i.)— Branches short, ascending; Ivs. lance-cuneiform, acute, pubescent 



at base ; Jis. terminal, sessile ; loiver valve of the a7ither 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" 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 XCVIII. CONVOLVULACE^.— Bindweeds. 



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



Lvs. alternate, without stipules, sometimes wholly wantinir. Fls. showy. 



Crt^.— .Sepals 5, much imbricated, usually united at base, persistent. 



Cor. regular, limb 5 lobcd or entire, plaited and twisted in estivation. 



Sta. 5, inserted into the base of the porolla and alternate with its lobes. 



Ova. 2— 4relled, free. Snjlef united into 1. 



Fr.— Capsule 2~4-celled, valves with septifragal dehiscence. 



Sd8. few, large, with thin mucilaginous albumen. Cotyledons foliaceous, or wanting. 



Genera 43, species 660, very abundant in tropical climates, rare in cold. 



Propert if.'}. —The roots abo'ond in an acrid, milky juice which is strongly purgative. Jalap ofthe shopi 



18 the product ofthe root of Exofronium purga of Mexico, and other species. Srammomj of Convolvulus 



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



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



Conspectus of the Genera. 



\ style simple. . 



t Stamens included. I Styles 3 or 2. . 



U^alyx naked. /Stamens exserted. Corolla scarlet 



J lealy, green. ( Calyx enclosed in two large, leaf hke bracts. . 



Plants ( leafless, parasitic, orange-colored 



Convolvulus. I 

 Stijlisma. 3 

 Quatiioclit. 2 

 ( "ahjstegia. 4 

 Cwcuta. S 



Suborder 1.— C O N V O li V U I. E J3 . 



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

 1. COXVOLVtTLUS. 



Lnt. amvolvrrc, to entwine ; from the habit of most of tlic plants. 



Calyx o-parted, naked or with 2 small bracts near the ba.so : cor. 

 campauulate, or funnel-form, limb r)-plaitcd : sta. shorter than the 

 limb, rnrolv n little longer: ova 2 — 4-ccllcd. cells 1 — ^-ovuled : stv 



