180 American Midland Naturalist Monograph No. 2 



3. Leaves elliptical, serrulate, pubescent beneath; twigs puberulent; flowers 

 4-merous; petals present; drupe with 2 nutlets; alluvial soil, bluffs, 

 river banks, the common species in 111. May R. lanceolate Pursh 



3. Leaves oval or obovate, strongly veined, glabrous, crenate-serrate; twigs 

 glabrous; flowers 5-merous; petals none; drupe with 3 nutlets; 

 wooded swamps, n. 111., in Lake and Peoria counties. Alder Buck- 

 thorn R. alnifolia L'Her. 



L Winter buds naked; leaves alternate; flowers 5-merous; shrubs or small trees 

 3-10 m. tall. 



4. Leaves serrate or serrulate; flowers in peduncled cymes, the pedicels pu- 

 bescent; ralyx-Iobes lanceolate, acuminate; drupe 8-10 mm. in diameter, 

 with 3 nutlets; wooded slopes, s. 111., rare; known from Jackson and 



Gallatin counties. May-June. Carolina Buckthorn 



R. caroliniana Walt. 



4. Leaves entire or undulate; flowers fascicled; pedicels glabrous; calyx-lobes 

 ovate, acute; drupe 6-8 mm. in diameter, with 2 nutlets; woods and 

 roadsides, nat. from Eurasia. Known in 111. from Lake, Cook, Sanga- 

 mon, and Champaign counties. May-June. Alder Buckthorn 



R. fratigula L. 



2. Ceanothus L. 



1 . Leaves ovate, acute; seeds smooth; thickets and open woods, coinmon. June- 

 July. New Jersey Tea C. americanus L. 



1. Leaves elliptic-lanceolate; seeds pitted; sandy soil in the n. third of III., not 

 common. May-June C ovatus Desf. 



103. Vitaceae Lindl. — Grape Family 



1 . Leaves simple, or pinnately compound. 



2. Inflorescence longer than broad; petals united in a cap, falling away without sep- 

 arating; pith interrupted at the nodes; fruit edible; leaves simple, palmately 



lobed or dentate 1. Vilis 



2. Inflorescence broader than long; petals separate, spreading; pith not interrupted at 



the nodes; fruit not edible 2. Ampelopsis 



1. Leaves palmately compound with usually 5-leaflets 3. Parihenocissiis 



1. Vitis L. — Grape 



1. Mature leaves grayish arachnoid-pubescent beneath. 



2. Twigs terete or nearly so, glabrate; fruit glaucous, about 1 cm. in diam- 

 eter; woods, thickets, and river banks in the n. two-thirds of the state. 

 June- July. [V. bicolor LeConte] Summer Grape ...V. aestivalis Michx. 



2. Twigs distinctly angular, permanently pubescent; fruit black, 6-8 mm. in 



diameter; woods and stream banks. June-July. Winter Grape 



V . cmerea Engelm. 



1. Mature leaves green beneath, short-pubescent along the veins, or nearly 

 glabrous. 



3. Leaves coarsely dentate or slighdy 3-lobed; fruit glaucous; in woods and 



along fences, common. May-June. [V . cordifolia Lam.] Frost Grape .... 

 V. vulpina L. 



