xxiv Keys Leaves Alternate 



190. 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. 



191. Twigs terete. p. 216. Microrhamnus. 

 Twigs 5-angled. p. 215. Condalia. 



192. With clustered stipules in the axils. p. 135. Prosopis. 

 Without bristly dwarf-branches. 193. 



193. Spines very pungent, beside the buds. 194. 



Spines less specialized twigs or branch-tips. 195. 



194. Bud-scales fleshy: twigs terete. p. 111. Crataegus. 

 Bud-scales dry: twigs angular. p. 103. Chaenomeles. 



195. Bundle-trace 1: Western. p. 219. Ceanothus. 

 Bundle-traces 3. 196. 



196. Leaf-scars linear or U-shaped. p. 104. Pyrus. 

 Leaf-scars broader: with stipule-scars. p. 127. Prunus. 



197. Leaf bases persistent and torn at top. p. 115. Rubus. 

 With clean-cut though sometimes shriveling leaf-scars. 198. 



198. Leaf-scars on articular membranes. p. 157. Robinia. 

 Leaf-scars relatively broad. p. 161. Zanthoxylum. 

 Leaf-scars small, elliptical or shriveled. p. 133. Acacia. 

 Leaf-scars linear or U-shaped. 199. 



199. Leaf-scars nearly encircling the thick stem. p. 260. Aralia. 

 Leaf-scars shorter: twigs not excessively stout. 200. 



200. Buds elongated and stalked: pith spongy. p. 82. Ribes. 

 Buds round-ovoid: pith continuous. 201. 



201. Leaf-scar U-shaped: bundle-traces 5. p. 259. Acanthopanax. 

 Leaf-scar nearly straight: bundle-traces 3. p. 123. Rosa. 



202. Bundle-traces 2: dwarf-twigs abundant. p. 3. Ginkgo. 

 Without this combination of characters. 203. 



203. Creeping or matted or heath-like evergreens. 204. 

 Not evergreen, or else not matted or heath-like. 219. 



204. Leaves revolute nearly or quite to the midrib. 205. 

 Leaves not revolute to the midrib. 208. 



