June, 1905.] Key to the Genera of Ohio Woody Plants. 369 



68. Leaves with gland-tipped serrations; terminal bud absent on ripe 

 twigs or if present then the lateral veins prominent and nearly 

 parallel and curving upward at the margin of the leaf; fruit a 

 berry-like drupe. Rhamnus. 



68. Leavesnot with gland-tipped serrations, or if so then not as above; 



terminal bud present ; fruit a pome. 69. 



69. Leaves sharply and regularly serrate, glabrous when mature, 



petioles long; pome with grit cells. Pyrus. 



69. Leaves irregularly dentate or serrate, or more or less lobed; pome 



without grit cells. Malus. 



70. Internodes very unequal; shrubs; fruit a capsule. Azalea. 



70. Internodes not very uneqvial. 71. 



71. Leaves sour, with prominent scattered hairs on the midrib beneath; 



trees; fruit a capsule. Oxydendrum. 

 7L Leaves not sour, nor as described above; shrubs. 72. 



72. Petiole slender, often one-half as long as the blade or longer; prom- 



inently mucronate or bristle-tipped; fruit a drupe. Ilicioides. 



72. Leaves short-petioled or sessile. 73. 



73. Older twigs finely white speckled or granvialted and blistered. 



Vaccinium. 



73. Twigs not white speckled or granulated, often with decurrent ridges. 



Spiraea. 

 —74— 



74. Plants with tendrils. 75. 



74. Without tendrils. 77. 



75. Monocotyls, with scattered vascular bundles and a pair of tendrils 



on the petiole. Smilax. 



75. Dicotyls with pith, a ring of wood, and true bark; tendrils opposite 



some of the leaves. 76. 



76. Older branches with woody partitions at the leaf nodes; bark 



brown, shreddy. Vitis. 



76. Branches without woody partitions; bark smooth, grayish-brown, 



not shreddy. Ampelopsis. 



77. Base of petiole covering the axillary bud; twigs with stipular rings. 



Platanus. 

 77. Axillary bud partly hidden; stems twining; no stipular rings. 



Menispermum. 



77. Axillary buds usually evident; stems not twining and twigs without 



stipular rings. 78. 



78. Leaves 2-ranked. 79. 



78. Leaves not 2-ranked. 84. 



79. Leaves entire, round-heart-shaped. Cercis. 



79. Leaves serrate, dentate, or lobed. 80. 



80. Pith usually in transverse plates; leaves ovate-lanceolate, inequi- 



lateral, taper-pointed. Celtis. 



80. Pith solid, not diaphragmed. 81. 



81. With milky sap. 82. 



81. Without rnilky sap. S3. 



82. Twigs gray or brown, glabrous or nearly so; leaves pubescent or 



glabrous beneath. Morus. 



82. Twigs grayish-green, downj^; leaves tomentose beneath. 



Broussonetia. 



83. Leaves not inequilateral ; vascular bundles in base of petiole 3. 



Betula. 



83. Leaves inequilateral at the base; vascular bundles in base of petiole 



several, scattered. Tilia. 



84. Leaves more or less star-shaped, with 3-7 long pointed serrate 



lobes, strongly aromatic when crushed; pith 5-angled. 



Liquidambar. 



