30 ACERACEAE. 



Vitis. Leaves simple ; petals united into a cap, falling away without separating; fruit 



pulpy, edible. 

 Cissus. Leaves simple in our species; petals separate, spreading; fruit scarcely pulpy, 



inedible. 

 Ampelopsis. Leaves digitate; corolla expanding. 



VITIS L. Shrubs, climbing by aid of coiling' tendrils, with dentate or pal- 

 mately lobed leaves, small caducous stipules, and fragrant thyrsoid flowers. 



V. riparia Mx. Leaves shining, glabrous, sometimes pubescent on the 

 veins beneath, sharply 5-7-lobed, sinuses acute, lobes coarsely toothed, acute. 

 Low woods; May-June; fruit ripening July-September; common. (V. vul- 

 pina L.) 



V. aestivalis Mx. Branches terete; leaves large, more or less deeply 3-5- 

 lobed, dentate, whitish or rusty pubescent especially when young; berries 

 black, with bloom. Reported from Clinton county by Arthur. 



V. cinerea Engelm. Branches angled; leaves dentate, somewhat 3-lobed; 

 pubescence whitish or grayish, persistent; berries black, without bloom. 

 Low woods; May-June, fruit ripe in September; Muscatine, Louisa, Page, 

 and Fremont counties. 



CISSUS L. Represented in our flora by the single species, 



C. ampelopsis Pers. Climbing, nearly glabrous; leaves ovate, coarsely 

 toothed, sometimes slightly 3-lobed, acuminate, base cordate or truncate; 

 berries 1-9-seeded. Low woods; May-June; Fremont county. (Ampelopsis 

 cor data Mx.) 



AMPELOPSIS Mx. Leaves digitate. Flower clusters cymose. Calyx 

 slightly 5-toothed. Petals 5, thick, spreading. Stamens 5. Tendrils attach- 

 ing by sucker-like disks. 



A. quinquefolia Mx. Vinginia Creeper. Climbing by rootlets as well as 

 by tendrils; leaflets stalked, oval to oblong-lanceolate, narrowed both ways, 

 usually 5, serrate above the middle, dark green above, pale beneath, turning 

 crimson in autumn. Thickets and low woods; July; fruit ripe in October; 

 common. (Partlienovlssus quinquefolia (L.) Planch.) 



ACERACEAE St. Hil. Maple Family. 



Trees or shrubs, with opposite palmately lobed or pinnate leaves, and 

 small regular unsymmetrial polygamous or dioecious flowers. Sepals and 

 petals 5, the latter often wanting, imbricated in the bud. Stamens 5-10; 

 filaments filiform. Ovary 2-lobed, 2-celled; styles 2, inserted between 

 the lobes. Fruit of 2 winged samaras, joined below, 1-seeded. Repre- 

 sented in our flora by the genus Acer L, the maples. 



* Leaves simple, palmately lobed; flowers polygamous. 



A. saccharinum L. Soft or White M. Usually 40-100 feet high; leaves 

 palmately 5-lobed, sinuses obtuse or acute, unequally toothed, silvery white 

 beneath and more or less downy when young, base truncate; flowers appear- 

 ing before the leaves, in umbel-like clusters, nearly sessile, greenish, apeta- 

 lous; fruit with large divergent wings. Rich soil; March-April; common. 

 (A. dasycarpum Ehrh.) A common grove tree. The sap yields small quanti- 

 ties of sugar. 



A. saccharum Marsh. Rock or Sugar M. A large tree; leaves dark green 

 above, pale beneath, 3-7-lobed, lobes sinuate, sinuses rounded and shallow, 

 base subcordate; flowers appearing with the leaves, in terminal or lateral 

 sessile corymbose clusters, apetalous, on drooping hairy pedicels; samaras 

 glabrous, slightly diverging, the wings shorter than the preceding. River 



