ARISTOLOCHIA 91 



ARISTOLOCHIA L. (Aristolochiaceae) 



Soft-wooded deciduous shrubs, climbing high into trees. Stems 

 terete, green, swollen at the nodes; pith large, rounded, contin- 

 uous, pale. Buds small, sessile, rounded, superposed on a silky 

 area, with 1 silky scale; terminal bud absent. Leaf-scars alternate, 

 U-shaped; bundle-traces 3; stipule-scars lacking. 



1. _A. durior Hill. Dutchman's Pipe. Pipe vine. ( A. macro- 

 phylla Lam.). A twining vine sometimes more than 10 m. high and 

 3 dm. in diameter, the branches slender, terete, green, glabrous; 

 pith large. Rich woods, mountains of Pennsylvania and West Vir- 

 ginia to Georgia and Alabama (Fig. 93). 



CLEMATIS L. (Ranunculaceae) 



Soft-wooded plants, climbing by bending or clasping of the 

 petioles. Stem 5- to 18-angled; pith angled or star-shaped, white, 

 continuous, with firmer diaphragms at the nodes. Buds small, 

 ovoid, or flattened, somewhat hairy, sessile, solitary, with 1-3 

 pairs of scales. Leaves opposite, withering but not falling, gradu- 

 ally torn off more or less piecemeal by winter winds. 



a. Stems glaucous and glabrous 3. C. verticillaris 



a. Stems not glaucous, sometimes 

 pubescent 



b. Stems brown, finely pubescent; 



leaflets toothed 1. C. virginiana 



b. Stems red-brown, pubescent at 



the nodes; leaflets entire . 2. C. viorna 



1. jC. virginiana L. Virgin's Bower. A climbing vine, more 

 or less woody; stem finely pubescent, brown, with about 6 distinct 

 ridges, leaves normally 3-foliate, the leaflets ovate, toothed. 

 Thickets, Quebec to Manitoba, south to Georgia, Louisiana, and 

 Kansas (Fig. 94). 



2. C. viorna L. Leather flower . A vine climbing to a height 

 of 3 m, or more; stem finely pubescent, red-brown; leaves mostly 

 pinnate, firm, entire. Rich soil of thickets, Georgia to Texas, 

 north to Pennsylvania and Iowa (Fig. 95). 



3. C^ verticillaris DC. Purple Virgin's Bower. A woody- 

 stemmed climber, glaucous and glabrous; stem 6-sided, brown; 

 leaves trifoliate. Rock slopes, Quebec to Wisconsin, south to 

 West Virginia and Iowa (Fig. 96). 



