i. Stipule-scars present.

j. Bud-scale only 1 visible; twigs brittle. SALIX; p. 34.

jj. Bud-scales 2 or more; twigs not brittle.

k. Bark smooth, close, warty or peeling into papery layers, but not flaky nor rough-ridged.

l. Tip of bud appressed; fruit berry-like. CELTIS, p. 131.

ll. Tip of bud not appressed; fruit not berry-like.

m. Trunk fluted; catkins not present in winter; lenticels not elongated horizontally; low tree or bushy shrub. CARPINUS, p.

83.

mm. Trunk not fluted; catkins usually present in winter; lenticels elongated horizontally; large trees. BETULA, p. 85.

kk. Bark flaky or rough-ridged, not warty nor peeling off in papery layers.

l. Bundle-scars depressed, conspicuous; bark thick, more or less deeply furrowed. ULMUS, p. 123.

ll. Bundle-scars not depressed, inconspicuous; bark thin, broken into narrow, flattish strips, loose at the ends.

OSTRYA, p. 81.

ii. Stipule-scars absent.

j. Buds silky-p.u.b.escent, depressed; twigs stout, clumsy, blunt, with conspicuous leaf-scars. GYMNOCLADUS, p. 163.

jj. Buds glabrous, not depressed; twigs slender, with inconspicuous leaf-scars.

k. Buds 1/8 inch long, obtuse, somewhat flattened and appressed; pith with reddish longitudinal streaks. CERCIS, p.

167.

kk. Buds 1/8-1/4 inch long, acute, not flattened nor appressed; pith without reddish streaks. PRUNUS, p. 153.

ff. Bundle-scars 4-many.

g. Bundle-scars in a single U-shaped line.

h. Terminal bud present; fruit berry-like; a shrub or small tree. PYRUS, p. 143.

hh. Terminal bud absent; fruit not berry-like; large trees.

i. Stipule-scars present; twigs slender.

j. Stipule-scars encircling the twig; leaf-scars nearly surrounding the bud; bark peeling off in thin plates, exposing the lighter colored inner bark. PLATa.n.u.s, p. 141.

jj. Stipule-scars not encircling the twig; leaf-scars not nearly surrounding the bud; bark thick, rough-ridged, not exposing the inner bark. ULMUS, p. 123.

ii. Stipule-scars absent; twigs very stout.

j. Bundle-scars usually not more than 5. GYMNOCLADUS, p. 163.

jj. Bundle-scars usually 6-12. AILANTHUS, p. 171.

gg. Bundle-scars variously grouped or scattered, but not in a single line.

h. Terminal bud present.

i. Stipule-scars present.

j. Stipule-scars encircling the twig; visible bud-scales 2, united. LIRIODENDRON, p. 137.

jj. Stipule-scars not encircling the twig; visible bud-scales more than 2, not united.

k. Buds 4 times as long as broad, not cl.u.s.tered at the tips of vigorous shoots; fruit a p.r.i.c.kly bur. f.a.gUS, p. 93.

kk. Buds not 4 times as long as broad, usually cl.u.s.tered at the tips of vigorous shoots; fruit an acorn. QUERCUS, p. 98.

ii. Stipule-scars absent. CARYA, p. 67.

h. Terminal bud absent (occasionally present in _Castanea_).

i. Bud at end of twig very obliquely unsymmetrical, mucilaginous when chewed. TILIA, p. 201.

ii. Bud at end of twig symmetrical, not mucilaginous when chewed.

j. Bud-scales 2-3 visible; pith star-shaped in cross-section; sap not milky; fruit a p.r.i.c.kly bur, present; large tree.

CASTANEA, p. 95.

jj. Bud-scales 4-8 visible; pith not star-shaped in cross-section; sap milky; fruit berry-like, not present; small tree. MORUS, p. 135.

MANUAL OF TREES

DESCRIPTION OF SPECIES

WITH

SUMMER AND WINTER KEYS

TO THE SPECIES

[Ill.u.s.tration: +Ginkgo. Maidenhair Tree+

1. Winter twig, 1/2.