CONVOLVULACEAE (CONVOLVULUS FAMILY) 671 



1. CALYSTEGIA (R. Br.) Gray. Stigmas oval to oblong ; calyx inclosed in 



2 broad leafy bracts. 



* Erect ; petioles at most one fourth as long as the leaf-blades. 



1. C. spithamadus L. Downy ; stem low and mostly simple, upright or as- 

 cending, 1.5-3 dm. long ; leaves broadly oblong, with or without a heart-shaped 

 or auricled base ; corolla white, 4-5 cm. long ; stigmas oval. Dry and sandy 

 or rocky soil, local. May-Aug. 



* * Twining or trailing ; petioles longer. 

 - Flowers double. 



2. C. jAp6Nicus Thunb. Pubescent ; leaves narrowly hastate ; flowers usu- 

 ally double, pink. Waste places, etc. , escaped from cultivation. (Introd. from 

 Asia.) 



-- H- Flowers single. 



3. C. sSpium L. (HEDGE B.) Glabrous or essentially so; stem high-twining 

 or sometimes trailing extensively; leaves triangular-halberd-shaped, acute or 

 pointed, the basal lobes obliquely truncate and often somewhat toothed or sinu- 

 ate-lobed or merely rounded ; peduncles chiefly elongated, 4-angled ; bracts 

 rounded to sharp-acuminate at tip ; corolla white or rose-color, 3-5 cm. long. 

 (Including var. americanus Sims.) Moist alluvial soil or along streams. June- 

 Sept. (Eurasia.) Passing freely to 



Var. pubescens (Gray) Fernald. More or less pubescent; stems trailing or 

 sprawling, 3-7 dm. long ; leaves oblong-ovate, cordate, the basal lobes obtuse or 

 rounded and entire. (Var. repens Gray; C. repens L.) Gravelly or marshy 

 sea-coast, e. Que. to Fla.; rare about the Great Lakes. 



Var. fraternifl6rus Mackenzie & Bush. More or less pubescent; leaves has- 

 tate ; flowers 1 or 2 in the axils, their peduncles mostly short and wing-angled. 



D. C. to Mo., and southw. 



2. STROPHOCAULOS G.Don. Stigmas filiform; no bracts at or near the 



base of the calyx. 



4. C. ARVENSIS L. (FIELD B.) Perennial; stem procumbent or twining, 

 and low ; leaves ovate-oblong, arrow- or halberd-shaped, with the lobes at the 

 base acute ; peduncles mostly 1 -flowered ; bracts minute, remote ; corolla 1.5-2 

 cm. long, white or tinged with red. Old fields and in waste places. June-Aug. 

 (Nat. from Eu.) Var. OBTusiFdLius Choisy. Basal lobes of the leaves rounded. 



Less common. (Adv. from Eu.) 



6. CUSCUTA [Tourn.] L. DODDER. LOVE VINE 



Calyx 5 (rarely 4) -cleft, or of 5 sepals. Corolla globular-urn-shaped, bell- 

 shaped, or short-tubular, the spreading border 5 (rarely 4) -cleft, imbricate. 

 Stamens with a scale-like often fringed appendage at base. Ovary 2-celled, 

 4-ovuled ; styles distinct, or rarely united. Capsule mostly 4-seeded. Embryo 

 spirally coiled in the rather fleshy albumen, sometimes with a few alternate 

 scales (belonging to the plumule) ; germination occurring in the soil. Leafless 

 annual herbs, with thread-like yellowish or reddish stems, bearing a few minute 

 scales in place of leaves ; on rising from the ground becoming entirely parasitic 

 on the bark of herbs and shrubs on which they twine, and to which they adhere 

 by means of suckers developed on the surface in contact. Flowers small, 

 cymose-clustered, mostly white, usually produced in summer and autumn. 

 (Name supposed to be of Arabic derivation.) 



1. Stigmas elongated; capsule circumscissile. 

 * Styles longer than the ovary and capsule. 



1. C. EpfLiNUM Weihe. (FLAX D.) Sterns very slender, low ; flowers yel- 

 lowish, globular, sessile in dense scattered heads ; corolla 5-parted, short-cylin- 

 drical, scarcely exceeding the broadly ovate acute divisions of the calyx, 



