Petioles slender, ½′ long.Beureria ([p. 861]). Petioles short and stout. Leaves coriaceous, with thick revolute margins (sometimes opposite).Jacquinia ([p. 804]). Leaves subcoriaceous, slightly revolute. Leaves reticulate-veined beneath. Leaves oval to obovate or oblong-oval, more or less pubescent while young.Vaccinium ([p. 802]). Leaves oblong to oblong-obovate, glabrous.Cyrilla ([p. 666]). Leaves obscurely veined beneath, glabrous. Leaves oblong-lanceolate, narrowed toward the emarginate apex, decurrent nearly to base of petiole.Cliftonia ([p. 667]). Leaves rounded at apex, distinctly petioled.Maytenus ([p. 676]).
** Leaves deciduous.
† Leaves conspicuous. (††, see [p. xxiv].)
a Leaves entire, sometimes 3 or 4-lobed. (aa, see [p. xxiii]). b Stipules present. Juice milky.Maclura ([p. 331]). Juice watery. Stipules connate, enveloping the young leaves, their scars encircling the branchlet. Leaves acute or acuminate, entire; winter-buds pointed, nearly terete.Magnolia ([p. 342]). Leaves truncate, sinuately 4-lobed; winter-buds obtuse, compressed.Liriodendron ([p. 351]). Stipules distinct. Branches spinescent; leaves glandular, caducous (crenately serrate on vigorous shoots).Dalea ([p. 621]). Branches not spinescent; leaves without glands. Winter-buds with a single pair of connate scales.Salix ([p. 138]). Winter-buds with several pairs of imbricate scales. Branchlets without a terminal bud; leaves 3-nerved.Celtis ([p. 318]). Branchlets with a terminal bud, leaves penniveined.Quercus sp. 17—20 ([p. 262]). bb Stipules wanting. c Branchlets bright green and lustrous for the first 2 or 3 years; leaves sometimes 3-lobed, aromatic.Sassafras ([p. 362]). cc Branchlets brown or gray. d Leaves acute or acuminate. Leaves 10′—12′ long, obovate-oblong, acuminate, glabrous, emitting a disagreeable odor.Asimina ([p. 353]). Leaves smaller. Petioles very slender, 1′—2′ long; leaves elliptic, acuminate.Cornus alternifolia ([p. 789]). Petioles short. Branchlets with a terminal bud. Leaf-scars about as long as broad; branchlets without lenticels, light reddish brown.Elliottia ([p. 791]). Leaf-scars crescent-shaped, broader than long, with 3 distinct bundle-traces. Leaves pubescent on both sides, rugulose above; petioles 1′—2′ long, like the young branchlet densely pubescent.Leitneria ([p. 167]). Leaves glabrous and smooth above, glabrous or pubescent below; petioles and branchlets usually glabrous or nearly so at maturity.Nyssa ([p. 779]). Branchlets without a terminal bud. Pubescence consisting of simple hairs or wanting. Leaves 4′—6′ long, pubescent beneath while young; branchlet light brown or gray.Diospyros virginiana ([p. 821]). Leaves 1½′—3′ long, glabrous; branches light yellowish gray.Schœpfia ([p. 336]). Pubescence stellate; leaves obovate or elliptic, 2½′—5′ long, pubescent below.Styrax ([p. 829]). dd Leaves obtuse or acute. Branchlets not spinescent. Leaves glabrous at maturity, their petioles slender.Cotinus ([p. 657]). Leaves pubescent below at maturity; their petioles short and thick.Diospyros texana ([p. 823]). Branchlets spinescent; leaves often fascicled on lateral branchlets.Bumelia ([p. 812]). aa Leaves serrate or pinnately lobed. b Stipules present. (bb, see [p. xxvi].) c Winter-buds naked. Leaves oblique at base, the upper side rounded or subcordate, obovate, coarsely toothed.Hamamelis ([p. 368]). Leaves equal at base, cuneate, finely serrate or crenate.Rhamnus sp. 2, 3 (p. [724], [725]). cc Winter-buds with a single pair of connate scales. Primary veins arching and uniting within the margins; leaves simply serrate or crenate, sometimes entire.Salix ([p. 138]). Primary veins extending to the teeth, leaves doubly serrate, often slightly lobed.Alnus ([p. 220]). ccc Winter-buds with several pairs of imbricate scales. d Terminal buds wanting; branchlets prolonged by an upper axillary bud. Juice milky; leaves usually ovate, often lobed.Morus ([p. 328]). Juice watery; leaves not lobed. Leaves distinctly oblique at base. Leaves with numerous prominent lateral veins. Leaves generally broad-ovate, simply serrate, stellate-pubescent at least while young, rarely glabrous.Tilia ([p. 732]). Leaves never broad-ovate, usually doubly serrate, more or less pubescent with simple hairs, at least while young. Winter-buds ovoid, usually acute, ⅓ to nearly as long as petioles; leaves 1′—7′ long, doubly serrate.Ulmus ([p. 309]). Winter-buds subglobose, minute; leaves 2′—2½′ long, crenate-serrate.Planera ([p. 316]). Leaves 3 or 4-nerved from the base.Celtis ([p. 318]). Leaves slightly or not at all oblique at base. Leaves 3-nerved from the base, glandular-crenate or glandular-serrate.Ceanothus ([p. 726]). Leaves not or obscurely 3-nerved at base, usually doubly serrate. Leaves blue-green; petioles ¼′—½′ long; bark smooth, gray-brown.Carpinus ([p. 201]). Leaves yellow-green. Bark rough, furrowed; petioles ⅛′—¼′ long; leaves not resinous-glandular.Ostrya ([p. 202]). Bark flaky or cherry-tree like; petioles ¼′—1′ long; leaves often resinous-glandular while young.Betula ([p. 205]). dd Terminal buds present. Primary veins arching and uniting within the margin (extending to the margin in the lobed leaves of Malus). Winter-buds resinous; leaves crenate, usually truncate at base; petioles slender.Populus ([p. 119]). Winter-buds not resinous. Leaf-scars with 3 bundle-traces. Leaves involute in bud, often lobed on vigorous shoots; winter-buds obtuse, short, pubescent.Malus ([p. 379]). Leaves conduplicate (or in some species of Prunus convolute), never lobed; winter-buds acute. Winter-buds elongated; branches never spinescent.Amelanchier ([p. 393]). Winter-buds not elongated, ovoid; branches sometimes spinescent.Prunus ([p. 555]). Leaf-scars with 1 bundle-trace; leaves simply serrate.Ilex sp. 5—6 ([p. 673]).
Primary veins extending to the teeth or to the lobes. Leaves lobed.Quercus sp. 1—16, 35—50 (p. [241], [283]). Leaves serrate-toothed. Winter-buds with numerous scales. Leaves lustrous beneath, remotely serrate or denticulate; winter-buds elongated, acuminate.Fagus ([p. 228]). Leaves pale beneath, coarsely dentate or serrate; winter-buds acute. Chestnut Oaks.Quercus sp. 51—54 ([p. 303]). Winter-buds with 2 pairs of scales.Castanea ([p. 230]). Leaves doubly or simply serrate, or lobed, with serrate lobes; branches often furnished with spines. Leaves involute in the bud; branchlets often ending in blunt spines.Malus ([p. 379]). Leaves conduplicate in the bud; branches usually armed with sharp-pointed single or branched axillary spines.Cratægus ([p. 397]). bb Stipules wanting. c Leaves not lobed. Leaves subcoriaceous, oblong, sometimes nearly entire, glabrous.Symplocos ([p. 831]). Leaves thin. Leaves oblong-obovate, acute, pubescent beneath.Gordonia alatamaha ([p. 752]). Leaves oblong or lanceolate, acuminate, glabrous or puberulous while young, turning scarlet in the autumn.Oxydendrum ([p. 796]). Leaves ovate to elliptic, stellate-pubescent or glabrous, turning yellow in the autumn.Halesia ([p. 824]). cc Leaves palmately lobed. Stipules large, foliaceous, united; branchlets without a terminal bud.Platanus ([p. 371]). Stipules small, free, caducous; branchlets with a terminal bud.Liquidambar ([p. 367]).
†† Leaves inconspicuous or wanting; branches spiny or prickly.
Branches or stems succulent, armed with numerous prickles. Branches and stems columnar, ribbed, continuous; leaves 0.Cereus ([p. 757]). Branches jointed, tuberculate; leaves scale-like.Opuntia ([p. 759]). Branches rigid, spinescent. Leaves minute, narrow-obovate. Branchlets bright green.Kœberlinia ([p. 754]). Branchlets red-brown.Dalea ([p. 621]). Leaves scale-like, caducous.Canotia ([p. 677]).
2. Leaves compound.
* Leaves 3-foliolate, without stipules.
Leaves persistent; leaflets obovate, entire, sessile.Hypelate ([p. 716]). Leaves deciduous. Leaflets deltoid to hastate, entire, rounded at apex; branches prickly.Erythrina ([p. 627]). Leaflets ovate to oblong, acuminate, strongly scented and bitter; branches unarmed.Ptelea ([p. 639]).