Xxiv 
190. 
191. 
192. 
193. 
194. 
195. 
196. 
197. 
198. 
199. 
200. 
201. 
202. 
203. 
204. 
KrEYS—LEAVES ALTERNATE 
Branches very green, terete. p. 142. Cercidium. 
Branches gray-green, flat-ribbed. p. 197. Glossopetalon. 
Branches very gray or white: Southwestern. 191. 
Branches neither conspicuously green nor white. 192. 
Twigs terete. p. 216. Microrhamnus. 
Twigs 5-angled. p. 215. Condalia. 
With clustered stipules in the axils. p. 135. Prosopis. 
Without bristly dwarf-branches. 193. 
Spines very pungent, beside the buds. 194. 
Spines less specialized twigs or branch-tips. 195. 
Bud-scales fleshy: twigs terete. p. 111. Crataegus. 
Bud-seales dry: twigs angular. p. 103. Chaenomeles. 
Bundle-trace 1: Western. p. 219. Ceanothus. 
Bundle-traces 3. 196. 
Leaf-scars linear or U-shaped. p. 104. Pyrus. 
Leaf-sears broader: with stipule-scars. p. 127. Prunus. 
Leaf bases persistent and torn at top. p. 115. Rubus. 
With clean-cut though sometimes shriveling leaf-scars. 198. 
Leaf-scars on articular membranes. p. 157. Robinia. 
Leaf-sears relatively broad. p. 161. Zanthoxylum. 
Leaf-secars small, elliptical or shriveled. p. 133. Acacia. 
Leaf-scars linear or U-shaped. 199. 
Leaf-scars nearly encircling the thick stem. p. 260. Aralia. 
Leaf-scars shorter: twigs not excessively stout. 200. 
Buds elongated and stalked: pith spongy. p. 82. Ribes. 
Buds round-ovoid: pith continuous. 201. 
Leaf-scar U-shaped: bundle-traces 5. p. 259. Acanthopanax. 
Leaf-scar nearly straight: bundle-traces 3. p.123. Rosa. 
Bundle-traces 2: dwarf-twigs abundant. p. 3. Ginkgo. 
Without this combination of characters. 203. 
Creeping or matted or heath-like evergreens. 204. 
Not evergreen, or else not matted or heath-like. 219. 
Leaves revolute nearly or quite to the midrib. 205. 
Leaves not revolute to the midrib. 208. 
