234 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



6. Ipomoea hederacea Jacq. 



Waste places and stubble fields. Aug.-Oct. Naturalized from tropical Amer- 

 (7. m7 of Ward's Flora.) 



2. CONVOLVULUS L. Bindweed. 



Bracts of the peduncle scalelike, remote from the calyx; stigmas linear; propagating 



by creeping roots 1. C. arvensis. 



Bracts of the peduncle leaflike, inclosing the calyx; stigmas oval to oblong; prop- 

 agating by creeping rootstocks. 

 Stems short and simple, erect or ascending; leaves oval or obovate, without lobes 



at the base or with very small ones 2. C. spithamaeus. 



Stems long, trailing or twining; leaves arrow-shaped, with large lobes at the base. 



3. C. sepium. 



1. Convolvulus arvensis L. 



Fields and waste ground, gradually becoming more common. May-Sept. Natu- 

 '"alized from Eurasia. 



2. Convolvulus spithamaeus L. 



Dry fields and woods; widely scattered but not common. May-June. Eastern N. 

 Amer. 



3. Convolvulus sepium L. 



Thickets, neglected fields, and waysides; abundant. May-Oct. Widely distrib* 

 uted in N. Amer. 



This species is variable and two or more forms may perhaps be separated. The 

 ^ ypical form is glabrous or nearly so, with the peduncles elongate and merely 4- 

 ngled. YaT.'/raterniJlorus Mack. & Bush is more or less pubescent, with shorter and 

 wing-angled peduncles. 



130. CUSCUTACEAE. Dodder Family. 



1. CUSCUTA L. Dodder. 



Calyx subtended by calyx-like bracts. Flowers sessile; bracts and calyx lobes 

 minutely ciliolate; corolla tube exceeding the calyx, contracted at the throat; 

 withering corolla capping the ovoid or oblate capsule, at length deciduous. 



5. C. compacta. 

 Calyx not subtended by bracts. 

 Flowers sessile or nearly so. Calyx lobes ovate, at least as long as the corolla tube. 

 Lobes of calyx and corolla 5 each; corolla lobes reflexed; scale ^ fringes usually 

 exposed; withering corolla persistent about the globose capsule. 



1. C. arvensis. 



Lobes of calyx and corolla 4 or 5 each; corolla lobes not reflexed; scales not 



exposed; withering corolla persistent at the base of the depressed-globose 



capsule 2. C. polygonorum. 



Flowers distinctly pediceled. 

 Calyx lobes 5 (rarely 4), triangular, acute; corolla tube exceeding the calyx, the 

 lobes erect, waxy white, their tips incurved; withering corolla surrounding 



the depressed-globose capsule 3. C. coryli. 



Calyx lobes 5, ovate; corolla campanulate, its tube about twice the length of the 

 calyx, its lobes spreading or reflexed; withering deciduous corolla at first 

 surrounding the ovoid or globose capsule 4. C. gronovii. 



1. Cuscuta arvensis Beyr. * Field dodder. 



On herbaceous plants generally within our range, the species commonly found on 

 weeds and clover in the vacant lots about Washington. June-Sept. Common 

 throughout the U. S. 



* The scales are small appendages on the inside of the corolla between the lobes. 



