June, 1905.] Key to the Genera of Ohio Woody Plants. 371 



101. Leaves 3-foliate, fragrant; axillary buds not superposed; bark 

 resinous or milky. Rhus. 



101. Leaves pinnate, not punctate. 102. 



102. Leaflets serrate; pith very large; bark resinous or milky. Rhus. 



102. Leaflets entire; pith small, bark not resinous or milky; trees. 



Cladrastis. 

 lOo. Leaflets entire or if occasionally few-toothed then the rachis 

 prominently winged. 104. 



103. Leaflets serrate or dentate, the rachis not winged. 105. 



104. Stipules large, meml)ranous and sheathing; leaflets 3-5, long silky. 



Dasiphora. 

 104. StijDules small, not sheathing; leaflets prominently mucronatc, bark 

 with strong odor. Amorpha. 



104. Stipules none, bark with a resinous or milkv sap, often poisonous. 



Rhus. 



105. With bristles or prickles; shrubs. 106. 



105. Without bristles or prickles; leaves pinnate. 107. 



105. Without bristles or brickies; leaves trifoliate, poisonous. Rhus. 



106. Leaves usually pinnate, the leaflets usually of about the same type, 



if 3-foliate then the petiole separates close to the bark leaving a 

 definite leaf scar; fruit an achene, a number inclosed in the fleshy 

 perigynous disc. Rosa. 



106. Leaves simple and lobed, or 3-7-foliate; if pinnate then the tenninal 



leaflet usually larger or broader than the others, petiole base 

 persistent ; fruit an aggregate of drupelets. Rubus. 



107. Pith cylindrical or nearly so; leaves with stipules; vascular bundles 



in base of petiole 3-5. 108. 



107. Pith 5-angled ; stipules none, base of petiole with numerous vascular 



bundles, scattered or in 3 areas. Hicoria. 



108. Trees; leaflets obtuse or acute at the apex. Sorbus. 



108. Shrubs; leaflets long acuminate. Sorbaria. 



109. Pith small; base of petiole covering the axillary buds; usually with 



prominent thorns. Gleditsia. 



109. Pith very large, base of petiole not covering the axillary buds; 



without thorns. Gymnocladus. 



— no- 

 il 0. Leaves simple. 116. 



110. Leaves compound with tendrils. Bignonia. 



110. Leaves compound, \vith 3 or more leaflets, petioles and petiolules 

 coiling; climbing vines. Clematis. 



110. Leaves compound without tendrils. 111. 



111. Leaves digitate with 5 or more leaflets. Aesculus. 



111. Leaves trifoliate or pinnate. 112. 



112. With numerous pit-like glands on top of the petiole near its base; 



vines climbing by rootlets. Tecoma. 



112. No glands on the top of the petiole; shrtibs or trees. 113. 



113. Base of petiole covering the axillary buds; leaflets dentate, lobed, 



or nearly entire. Acer. 



113. Base of petiole not covering the axillary buds. 114. 



114. Leaves trifoliate, serrate; bark with strong odor. Staphylea. 



114. Leaflets 5-11. 115. 



115. Leaves often with gland-tipped stipels ; pith large ; shrubs. Sambucus. 



115. Leaves without stipels; pith small; trees. Fraxinus. 



—116— 



116. Leaves pinnately veined. 123. 



116. Leaves palmately veined or at least with 2 prominent side ribs from 



the base. 117. 



117. Leaves entire or if somewhat 3-lobed with entire margin. 118. 



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