194 VITACEAE 



Distribution. — The Riverbank Grape, as its name infers, 

 prefers low, alluvial soil along streams. It ranges from New 

 Brunswick to Manitoba and south to Virginia and Texas. In 

 Illinois, it is a very common and abundant grape, distributed 

 through the length and breadth of the state. In prairie regions, 

 however, small streams without floodplains do not support it. 



AMPELOPSIS Michaux 

 Ampelopsis 



The Ampelopsis genus consists of climbing vines with a few 

 tendrils, alternate, simple or pinnately compound leaves and, 

 for the most part, perfect flowers arranged in cymes. There 

 are 5 sepals, and the 5 petals are distinct and expand into a 

 flower. The ovary is 2-celled and capped by a slender style. 

 The fruit is a berry which, at maturity, is nearly dry and 

 contains 2 to 4 seeds. 



There are about 15 species, all natives of temperate and 

 warm regions. Two are known to occur in North America; 

 one is native in Illinois. The distinction between Ampelopsis 

 and Parthenocissus is quite technical. For Illinois species, ten- 

 drils furnish the most reliable character, those of Parthenocis- 

 sus having adhesion disks, those of Ampelopsis having none. 



AMPELOPSIS CORDATA Michaux 

 Heartleaf Ampelopsis 



The Heartleaf Ampelopsis, fig. 49, is a large climbing vine 

 with tight, sometimes deeply furrowed bark and unbranched 

 tendrils which often end in a disk. The leaves are ovate to 

 broadly ovate, sometimes fully as wide as long, and commonly 

 2 to 5 inches long. They are acuminate at the apex and cordate, 

 less often truncate, at the base, and the margin is coarsely and 

 irregularly toothed and often provided with 2 short lateral 

 lobes. The surface is smooth, both above and beneath, except 

 for a few hairs on the veins at the base of the leaf, and the 

 under surface commonly is lighter green than the upper. The 

 petioles are about one-half as long as the blade, and the basal 

 half is smooth, while the upper half is more or less pubescent. 



The small flowers occur in panicles of 25 to 70 opposite the 

 leaves, or sometimes in smaller panicles on the branches of 



