CUSCUTACEAE 153 



corolla light blue, purple, red or white. — Often abundant in waste places. 

 July-October. 



4. I. hederacea Jacq. Corn-field Morning Glory. Like the 

 last but leaves 3-parted, the sepals acuminate-pointed, and flowers light 

 blue. — This is often very common in fields, especially in the Missouri 

 Kiver bottoms. July-October. 



3. CONVOLVULUS L. 



Corolla funnel-form to campanulate. Our species are perennials with 

 showy pink or white flowers. 



Calyx with two large bracts at base. 



Flowers single. 1. C. sepium. 



Flowers double. 2. C. Japonicus. 



Calyx without bracts at base. 3. C. arvensis. 



1. C. sepium L. Bindweed. 3°-12° long, glabrous or pubescent : 

 leaves triangular-hastate, glabrous or pubescent below, but nearly always 

 glabrous above, the basal lobes obliquely truncate : one peduncle in the 

 axil of each leaf. — Common throughout in sunny places. June-Sep- 

 tember. 



Var. fraterniflorus Mackenzie & Bush, n. var. Leaves 3^-4^ long, 

 strongly appressed-pubescent on both sides : two 1-flowered peduncles in 

 the axil of each leaf, the one longer and the other shorter than the petiole : 

 flowers white. — Dry banks near Martin City. July. 



2. C. Japonicus Thunb. Japanese Morning Glory. A few ftet 

 long : leaves narrowly hastate : flowers pink, doable. — Thoroughly estab- 

 lished along the railroad at Sibley. July-September. 



3. C. arvensis L. Small Bindweed. l°-3° long, glabrous : leaves 

 ovate-oblong, sagittate, the basal lobes spreading, acute : peduncles 1-3- 

 flowered, bearing some small bracts. — Along railroads and in waste places 

 in about a dozen widely separated localities. — May-September. 



Family 103. CUSCUTACEAE Dumort. 



"Whitish or yellowish parasites with scale-like leaves and flowers as in 

 CoNVOLVULACEAE. Cotyledons none. The lower part of the stems en- 

 tirely disappear at flowering time and leave the plants wholly dependent 

 on their host. 



1. CUSCUTA L. Dodder. 



Flowers white, cymose-clustered, often bracted at base. Corolla with 

 scales in its throat. Capsule indehiscent (in ours). 



Calyx gamosepalous. 

 Corolla lobes acute. 



Calyx lobes obtuse. 1. C. arvensis. 



Calyx lobes acute. 



Flowers nearly sessile. 2. C. Polygonorum. 



Flowers distinctly pedicelled. 3. C. Coryli. 



