CONVOLVULUS. XCVIII. CONVOLVULACE^E. 441 



ORDER XCVIL DIAPENSIACE^E. 



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



Col. Sepals 5, much imbricated, surrounded at base v/ith 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 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 

 uridershrubs. 



J . Anthers awnless. 



1. D. LAPPONICA. Northern Diapensia. 



Csespitose ; Ivs. dense, spatulate, fleshy, evergreen, obtuse and entire ; Jin. 

 pedunculated. 7}. A little, leafy plant, 2 3' high, growing on the summits of 

 the White Mts. in N. Hampshire, forming dSnse tufts among the rocks. Leave* 

 crowded, pale beneath, fleshy, 5- 8" by I" 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. (Pyxidanthcra barbulata. Michx. P. cuneifoha, 

 Ph.} Branches short, ascending; Ivs. lance-cuneiform, acute, pubescent 



at base ; fls. terminal, sessile ; lower valve of ike 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 | 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. C ON VOLVULACEJE. 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. 



Cor. 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 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. Jfltapofthe shop* 



is the product of the root of Exogonium purga of Mexico, and other species. Scammony of Convolvuliw 



Scammonia, native of Levant. The drastic qualities of both depend upon the presence of a peculiai 



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



Conspectus of Ike Genera. 



\ Style simple Convolvulus, l 



$ Stamens included. Styles 3 or 2 Stylisma. 3 



J Calyx naked. (Stamens exserted. Corolla scarlet. . . . Quamocltt. 2 



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



Plants < leafless, parasitic, orange-colored Cwcuta. 6 



SUBORDER 1. C ONVOL.VULEJB. 



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

 1. CONVOLVtJLTJS. 



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 2-ovuled ; sty 



