CONVOLVULUS. XCVIII. CONVOLVULACE.E. 441 



ORDER XCVIL DIAPENSIACE^B. 



Under shrubs, prostrate, with crowded, heath-like leaves and solitary, terminal flowers. 



Col. Sepals 5, much imbricated, surrounded at base with imbricated scales. 



Cor. Petals 5, united, regular, imbricated in aestivation. 



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



Anth. 2-celled, transversely valved. 



Ova. 3-.celled, free. Styles united into 1. Stigma 3-lobed. 



Pr. Capsule 3-valved, loculicidal. Seeds many, small, albuminous. 



Genus l, 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. 



J . Anthers awnless. 



1. D. LAPPONICA. Northern Diapensia. 



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

 pedunculated. fy 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. BARBULATA. Ell. (Pyxidanthera barbulata. Michx. D. cuneifolia. 

 PA.) Branches short, ascending; Ivs. lance-cuneiform, acute, pubescent 



at base ; fls. 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" by J 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 juice, mostly twining, sometimes erect. 



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



Cal. Sepals 5, much imbricated, usually united at base, persistent. 



Car. regular, limb 5 lobed or entire, plaited and twisted in aestivation. 



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 fohaceous, 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 strongjy purgative. Jalap 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. 



$ Style simple Convolvulus. I 



Stamens included. ( Styles 3 or 2 Stylisma. 3 



$ Calyx naked. ( Stamens exserted. Corolla scarlet . . . Quamoclit, 2 



(leafy, green. { Calyx enclosed in two large, leaf-like bracts. . . '. . . Calystegia. 4 



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



SUBORDER 1. C OXVOLVTJIvE-E. 



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 5 cells 1 2-ovuled ; sty, 



