cc. Thorns or spines much exceeding 14 inch in length on 
the branches. 
d. Thorns usually branched, situated above the nodes; 
lateral buds superposed, the lower covered by bark; 
fruit a flat pod...............05 GLEDITSIA, p. 165. 
dd. Thorns unbranched on twigs, situated at the nodes; 
lateral buds not superposed, not covered by bark; 
fruit a small pome............ CRATAEGUS, p. 151. 
bb. Twigs, branches or trunks unarmed. 
c. Leaf-scars mainly crowded on short, stout, lateral shoots. 
d. Bundle-scar 1; fruit a cone, usually present.......... 
CLovsraenridus mii eelndew ove oe vehawas LARIX, p. 17. 
dd. Bundle-scars 2; fruit a globose drupe falling in 
AULUMIN vaca acd wininsiata nook ea ea acess GINKGO, p. 3. 
cc. Leaf-scars distributed along the lateral branches. 
d. Leaf-scars (or some of them) 3 at a node, i. e, 
Whorled a enaneseedvue osndes seQuee CATALPA, p. 223. 
dd. Leaf-scars 1-2 at a node, i. e., not whorled. 
e. Leaf-scars 2 at a node, i. e., opposite. 
f. Terminal buds %4-1%4 inches long, resin-coated; 
twigs very stout............. AESCULUS, p. 195. 
ff. Terminal buds rarely exceeding %4 inch in length, 
not resin-coated; twigs not conspicuously stout. 
g. Leaf buds with 1 pair of scales visible. 
h, Buds scurfy-pubescent.. VIBURNUM, p. 229. 
hh. Buds glabrous...... Siaateans CORNUS, p. 203. 
gg. Leaf buds with 2 or more pairs of scales visible. 
th. Bundle-scars usually 3, distinct, separated.. 
ars han State cedtansraniantlatae dots stonttameks ACER, p. 174. 
hh, Bundle-scars many, minute, more or less con- 
fluent in a U-shaped line................... 
ssa aes auaesmeund ale ex dee FRAXINUS, p. art. 
ee. Leaf-scars I at a node, i. e., alternate. 
f. Bundle-scars 1-3. 
g. Bundle-scar only 1, or appearing as I. 
h. Twigs bright green, spicy-aromatic; bundle- 
scar appearing as a horizontal line; terminal 
bud present; pith homogeneous............. 
are hasa(inia tetas tates ae SASSAFRAS, p. 139. 
— XXVIII — 
