XVI. Magnoliaceæ ([p. 342]). Flowers perfect; sepals and petals in 3 or 4 rows of 3 each; fruit cone-like, composed of numerous cohering carpels; leaves simple, alternate, their stipules inclosing the leaf-buds, deciduous or rarely persistent. XVII. Anonaceæ ([p. 353]). Flowers perfect; sepals 3; petals 6 in 2 series; fruit a pulpy berry developed from 1 or from the union of several carpels; leaves simple, alternate, without stipules, deciduous or persistent. XVIII. Lauraceæ ([p. 356]). Flowers perfect or unisexual; corolla 0; fruit a 1-seeded drupe or berry; leaves simple, alternate, punctate, without stipules, persistent (deciduous in Sassafras). XIX. Capparidaceæ ([p. 365]). Flowers perfect; sepals and petals 4; fruit baccate, elongated, dehiscent; leaves alternate, simple, without stipules, persistent. XX. Hamamelidaceæ ([p. 366]). Flowers perfect or unisexual; sepals and petals 5 (corolla 0 in Liquidambar); ovary partly inferior; fruit a 2-celled woody capsule opening at the summit; leaves simple, alternate, with stipules, deciduous. XXI. Platanaceæ ([p. 371]). Flowers monœcious, in dense unisexual capitate heads; fruit an akene; leaves simple, alternate, with stipules, deciduous. XXII. Rosaceæ ([p. 376]). Flowers perfect; sepals and petals 5 (petals 0 in Cercocarpus); ovary inferior in Malus, Sorbus, Heteromeles, Cratægus, and Amelanchier; fruit a drupe (Prunus and Chrysobalanus), a capsule (Vauquelinia and Lyonothamnus), an akene (Cowania and Cercocarpus), or a pome (Malus, Sorbus, Heteromeles, Cratægus, and Amelanchier); leaves simple or pinnately compound, alternate (opposite in Lyonothamnus), with stipules, deciduous or persistent. XXIII. Leguminosæ ([p. 585]). Flowers perfect, regular or irregular; fruit a legume; leaves compound, or simple (Dalea), alternate, with stipules, deciduous or persistent. XXIV. Zygophyllaceæ ([p. 630]). Flowers perfect; calyx 5-lobed; petals 5; fruit capsular, becoming fleshy; leaves opposite, pinnate, with stipules, persistent. XXV. Malpigiaceæ ([p. 631]). Flowers usually perfect rarely dimorphous; calyx 5-lobed; petals 5, unguiculate; fruit a drupe or samara; leaves opposite, simple, entire, persistent; often with stipules. XXVI. Rutaceæ ([p. 633]). Flowers unisexual or perfect; fruit a capsule (Xanthoxylum), a samara (Ptelea), of indehiscent winged 1-seeded carpels (Helietta), or a drupe (Amyris); leaves alternate or opposite, compound, glandular-punctate, without stipules, persistent or rarely deciduous (0 in Canotia). XXVII. Simaroubaceæ ([p. 641]). Flowers diœcious, calyx 5-lobed; petals 5; fruit drupaceous (Simarouba), baccate (Picramnia), a samara (Alvaradoa); leaves alternate, equally pinnate, without stipules, persistent. XXVIII. Burseraceæ ([p. 645]). Flowers perfect; calyx 4 or 5-parted; petals 5; fruit a drupe; leaves alternate, compound, without stipules, deciduous. XXIX. Meliaceæ ([p. 648]). Flowers perfect; calyx 5-lobed; petals 5; fruit a 5-celled dehiscent capsule; leaves alternate, equally pinnate, without stipules, persistent. XXX. Euphorbiaceæ ([p. 649]). Flowers perfect; calyx 4—6-parted (Drypetes), 3-lobed (Hippomane), or 0 (Gymnanthes); petals 0; fruit a drupe (Drypetes and Hippomane), or a 3-lobed capsule (Gymnanthes). XXXI. Anacardiaceæ ([p. 655]). Flowers usually unisexual, diœcious or polygamo-diœcious (Pistacia without a calyx, and without a corolla in the North American species); fruit a dry drupe; leaves simple or compound, alternate, without stipules, deciduous (persistent in Pistacia and in one species of Rhus). XXXII. Cyrillaceæ ([p. 665]). Flowers perfect; calyx 5—8-lobed; petals 5—8; fruit an indehiscent capsule; leaves alternate, without stipules, persistent (more or less deciduous in Cyrilla). XXXIII. Aquifoliaceæ ([p. 668]). Flowers polygamo-diœcious; calyx 4 or 5-lobed; petals 5; fruit a drupe, with 4—8 1-seeded nutlets; leaves alternate, simple, with stipules, persistent or deciduous. XXXIV. Celastraceæ ([p. 674]). Flowers perfect, polygamous or diœcious; calyx 4 or 5-lobed; petals 4 or 5; fruit a drupe, or a capsule (Evonymus); leaves simple, opposite or alternate, with or without stipules, persistent (deciduous in Evonymus). XXXV. Aceraceæ ([p. 681]). Flowers diœcious or monœciously polygamous; calyx usually 5-parted; petals usually 5, or 0; fruit of 2 long-winged samara joined at the base; leaves opposite, simple or rarely pinnate, without or rarely with stipules, deciduous. XXXVI. Hippocastanaceæ ([p. 702]). Flowers perfect, irregular; calyx 5-lobed; petals 4 or 5, unequal; fruit a 3-celled 3-valved capsule; leaves opposite, digitately compound, long-petiolate, without stipules, deciduous. XXXVII. Sapindaceæ ([p. 711]). Flowers polygamous; calyx 4 or 5-lobed; corolla of 4 or 5 petals; fruit a berry (Sapindus and Exothea), a drupe (Hypelate), or a 3-valved capsule (Ungnadia); leaves alternate, compound, without stipules, persistent, or deciduous (Ungnadia). XXXVIII. Rhamnaceæ ([p. 718]). Flowers usually perfect; calyx 4 or 5-lobed; petals 4 or 5 (0 in Reynosia, Condalia, and Krugiodendron); fruit drupaceous; leaves simple, alternate (mostly opposite in Reynosia and Krugiodendron), with stipules, persistent (deciduous in some species of Rhamnus). XXXIX. Tiliaceæ ([p. 732]). Flowers perfect; sepals and petals 5; fruit a nut-like berry; leaves simple, alternate, mostly oblique at base, with stipules, deciduous. XL. Sterculiaceæ ([p. 749]). Flowers perfect; calyx 5-lobed; petals 0; fruit a 4 or 5-valved dehiscent capsule; leaves simple, alternate, with stipules, persistent. XLI. Theaceæ ([p. 750]). Flowers perfect; sepals and petals 5; fruit a 5-celled woody dehiscent capsule, loculicidally dehiscent; leaves simple, alternate, without stipules, persistent or deciduous. XLII. Canellaceæ ([p. 753]). Flowers perfect; sepals 3; petals 5; filaments united into a tube; fruit a berry; leaves simple, alternate, without stipules, persistent. XLIII. Kœberliniaceæ ([p. 754]). Flowers perfect; sepals and petals 4, minute; leaves bract-like, alternate, without stipules, caducous. XLIV. Caricaceæ ([p. 755]). Flowers unisexual or perfect; calyx 5-lobed; petals 5; fruit baccate; leaves palmately lobed or digitate, alternate, without stipules, persistent.

B. Ovary inferior (partly inferior in Rhizophora).

XLV. Cactaceæ ([p. 757]). Flowers perfect; petals and sepals numerous; fruit a berry; leaves usually wanting. XLVI. Rhizophoraceæ ([p. 763]). Flowers perfect; calyx 4-parted; petals 4; ovary partly inferior; fruit a 1-celled 1-seeded berry perforated at apex by the germinating embryo; leaves simple, opposite, entire, with stipules, persistent. XLVII. Combretaceæ ([p. 764]). Flowers perfect or polygamous; calyx 5-lobed; petals 5 (0 in Conocarpus); fruit drupaceous; leaves simple, alternate or opposite, without stipules, persistent. XLVIII. Myrtaceæ ([p. 768]). Flowers perfect; calyx usually 4-lobed, or reduced to a single body forming a deciduous lid to the flower (Chytraculia); petals usually 4 (0 in Chytraculia); fruit a berry; leaves simple, opposite, pellucid-punctate, without stipules, persistent. XLIX. Melastomaceæ ([p. 776]). Flowers perfect; calyx and corolla 4 or 5-lobed; stamens as many or twice as many as the lobes of the corolla; fruit capsular or baccate, inclosed in the tube of the calyx; leaves opposite, rarely verticillate, 3—9-nerved, without stipules. L. Araliaceæ ([p. 777]). Flowers perfect or polygamous; sepals and petals usually 5; fruit a drupe; leaves twice pinnate, alternate, with stipules, deciduous. LI. Nyssaceæ ([p. 779]). Flowers diœcious, polygamous, diœcious or perfect; calyx 5-toothed or lobed; petals 5 or more, imbricate in the bud, or 0; stamens as many or twice as many as the petals; fruit drupaceous (Nyssa), usually 1-celled and 1-seeded; leaves alternate, deciduous, without stipules. LII. Cornaceæ ([p. 784]). Flowers perfect or polygamo-diœcious; calyx 4 or 5-toothed; petals 4 or 5; fruit a fleshy drupe; leaves simple, opposite (alternate in one species of Cornus), without stipules, deciduous.

Section 2. Gamopetalæ. Corolla of united petals (divided in Elliottia in Ericaceæ, 0 in some species of Fraxinus in Oleaceæ).

A. Ovary superior (inferior in Vaccinium in Ericaceæ, partly inferior in Symplocaceæ and Styracaceæ).

LIII. Ericaceæ ([p. 790]). Flowers perfect; calyx and corolla 5-lobed (in Elliottia corolla of 4 petals); (ovary inferior in Vaccinium); fruit capsular, drupaceous or baccate; leaves simple, alternate, without stipules, persistent (deciduous in Elliottia and Oxydendrum). LIV. Theophrastaceæ ([p. 804]). Flowers perfect, with staminodia; sepals and petals 5; stamens 5; fruit a berry; leaves simple, opposite or alternate, entire, without stipules. LV. Myrsinaceæ ([p. 805]). Flowers perfect; calyx and corolla 5-lobed; stamens 5; fruit a drupe; leaves simple, alternate, entire, without stipules, persistent. LVI. Sapotaceæ ([p. 808]). Flowers perfect; calyx 5-lobed; corolla 5-lobed (6-lobed in Mimusops), often with as many or twice as many internal appendages borne on its throat; fruit a berry; leaves simple, alternate, without stipules, persistent (deciduous in some species of Bumelia). LVII. Ebenaceæ ([p. 820]). Flowers perfect, diœcious, or polygamous; calyx and corolla 4-lobed; fruit a 1 or several-seeded berry; leaves simple, alternate, entire, without stipules, deciduous. LVIII. Styraceæ ([p. 824]). Flowers perfect; calyx 4 or 5-toothed; corolla 4 or 5-lobed or divided nearly to the base, or rarely 6 or 7-lobed; ovary superior or partly superior; fruit a drupe; leaves simple, alternate, without stipules, deciduous; pubescence mostly scurfy or stellate. LIX. Symplocaceæ ([p. 830]). Flowers perfect; calyx and corolla 5-lobed; ovary inferior or partly inferior; fruit a drupe; leaves simple, alternate, without stipules, deciduous; pubescence simple. LX. Oleaceæ ([p. 832]). Flowers perfect or polygamo-diœcious; calyx 4-lobed (0 in some species of Fraxinus); corolla 2—6-parted (0 in some species of Fraxinus); fruit a winged samara (Fraxinus) or a fleshy drupe (Forestiera, Chionanthus and Osmanthus); leaves pinnate (Fraxinus) or simple, opposite, without stipules, deciduous (persistent in Osmanthus). LXI. Borraginaceæ ([p. 858]). Flowers perfect or polygamous; calyx and corolla 5-lobed; fruit a drupe; leaves simple, alternate, scabrous-pubescent, without stipules, persistent or tardily deciduous. LXII. Verbenaceæ ([p. 864]). Flowers perfect; calyx 5-lobed; corolla 4 or 5-lobed; fruit a drupe or a 1-seeded capsule; leaves simple, opposite, without stipules, persistent. LXIII. Solanaceæ ([p. 867]). Flowers perfect; calyx campanulate, usually 5-lobed; corolla usually 5-lobed; fruit baccate, surrounded at base by the enlarged calyx; leaves alternate, rarely opposite, without stipules. LXIV. Bignoniaceæ ([p. 868]). Flowers perfect; calyx bilabiate; corolla bilabiate, 5-lobed; fruit a woody capsule (Catalpa and Chilopsis) or a berry (Enallagma); leaves simple, opposite (sometimes alternate in Chilopsis), without stipules, deciduous (persistent in Enallagma).

B. Ovary inferior (partly superior in Sambucus in Caprifoliaceæ).

LXV. Rubiaceæ ([p. 875]). Flowers perfect; calyx and corolla 4 or 5-lobed; fruit a capsule (Exostema and Pinckneya), a drupe (Guettarda), or nut-like (Cephalanthus); leaves simple opposite, or in verticils of 3 (Cephalanthus), with stipules, persistent (deciduous in Pinckneya and Cephalanthus). LXVI. Caprifoliaceæ ([p. 882]). Flowers perfect; calyx and corolla 5-lobed; fruit a drupe; leaves unequally pinnate (Sambucus) or simple (Viburnum), opposite, without stipules, deciduous in North American species.

ANALYTICAL KEY
TO THE GENERA OF PLANTS INCLUDED IN THIS BOOK, BASED CHIEFLY ON THE CHARACTER OF THE LEAVES

I. Leaves parallel-veined, alternate, persistent, clustered at the end of the stem or branches. Monocotyledons. Stem simple; leaves stalked. Leaves fan-shaped. Leaf stalks unarmed. Rachis short; leaves usually silvery white below. Leaves 2°—4° in diameter (green below in No. 2), their segments undivided at apex.Thrinax ([p. 96]). Leaves 18′—24′ in diameter, their segments divided at apex.Coccothrinax ([p. 100]). Rachis elongated; leaves green below, their segments divided at apex.Sabal ([p. 101]). Leaf stalks armed with marginal teeth or spines. Leaf stalks furnished irregularly with broad thin large and small, straight or hooked spines confluent into a thin bright orange-colored cartilaginous margin; leaves longer than wide, divided nearly to the middle into segments parted at apex and separating on the margins into thin fibres.Washingtonia ([p. 104]). Leaf stalks furnished with stout or slender flattened teeth; leaves suborbicular, divided to the middle or nearly to the base into segments parted at apex; segments of the blade not separating on the margin into thin fibres.Acœlorraphe ([p. 105]). Leaves pinnate. Leaves 10°—12° in length, their pinnæ 2½°—3° long and often 1½° wide, deep green.Roystonea ([p. 107]). Leaves 5°—6° long, their pinnæ 18′ long and 1′ wide, dark yellow-green above, pale and glaucous below.Pseudophœnix ([p. 109]). Stem simple or branched; leaves sessile, lanceolate, long- and usually sharp-pointed at apex.Yucca ([p. 110]).