Part 2

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).

II. Leaves 1-nerved, needle-shaped, linear or scale-like, persistent (deciduous in Larix and Taxodium). Gymnospermæ.

1. Leaves Persistent.

_a_ Leaves fascicled, needle-shaped, in 1—5-leafed clusters enclosed at base in a membranaceous sheath. Pinus (p. 2). _aa_ Leaves scattered, usually linear. _b_ Leaves linear, often obtuse or emarginate. Base of the leaves persistent on the branches. Leaves sessile, 4-sided, or flattened and stomatiferous above. Picea (p. 34). Leaves stalked, flattened and stomatiferous below, or angular, often appearing 2-ranked. Tsuga (p. 42). Base of the leaves not persistent on the branches; leaves often appearing 2-ranked. Leaves stalked, flattened, stomatiferous below; winter-buds pointed, not resinous. Pseudotsuga (p. 47). Leaves sessile, flattened and often grooved on the upper side, or quadrangular, rarely stomatiferous above, on upper fertile branches often crowded; winter-buds obtuse, resinous (_except in No. 9_). Abies (p. 50). _bb_ Leaves linear-lanceolate, rigid, acuminate, spirally disposed, appearing 2-ranked by a twist in the petiole. Leaves abruptly contracted at base, long-pointed, with pale bands of stomata on the lower surface on each side of the midveins; fruit drupe-like. Torreya (p. 91). Leaves gradually narrowed at base, short-pointed, paler, and without distinct bands of stomata on the lower surface; fruit berry-like. Taxus (p. 93). _bbb_ Leaves ovate-lanceolate and scale-like, spreading in 2 ranks or linear on the same tree, acute, compressed, keeled on the back and closely appressed or spreading at apex. Sequoia (p. 61). _aaa_ Leaves opposite or whorled, usually scale-like.

Internodes distinctly longer than broad; branchlets flattened, of nearly equal color on both sides; leaves eglandular. Libocedrus (p. 65). Internodes about as long as broad, often pale below, usually glandular. Branchlets flattened. Branchlets in one plane, much flattened, 1/12′—⅙′ broad. Thuya (p. 67). Branchlets slightly flattened, 1/24′—1/16′ broad. Chamæcyparis (p. 75). Branchlets terete or 4-angled. Branchlets more or less in one plane; fruit a cone. Cupressus (p. 69). Branchlets not in one plane; fruit a berry (_leaves needle-shaped, in whorls of 3 in No. 1_). Juniperus (p. 78).

2. Leaves Deciduous.

Leaves in many-leafed clusters on short lateral spurs. Larix (p. 31). Leaves spreading in 2 ranks. Taxodium (p. 63).

III. Leaves netted-veined, rarely scale-like or wanting. Dicotyledons.

A. LEAVES OPPOSITE. (B, see p. xix).

1. Leaves Simple. (2, see p. xviii).

Leaves persistent.

_a_ Leaves with stipules. _b_ Leaves entire or occasionally slightly crenate or serrate. _c_ Leaves emarginate at apex, very short-stalked, 1½′—2′ long. Leaves obovate, gradually narrowed into the petiole. Gyminda (p. 678). Leaves oval to oblong, rounded or broad-cuneate (_rarely alternate_). Branchlets densely velutinous. Krugiodendron (p. 721). Branchlets slightly puberulous at first, soon glabrous. Reynosia (p. 720). _cc_ Leaves not emarginate at apex. Leaves obtuse, rarely acutish or abruptly short-pointed. Leaves elliptic, 3½′—5′ long. Rhizophora (p. 763). Leaves obovate, usually rounded at apex, ¾′—2′ long. Byrsonima (p. 632). Leaves acute to acuminate. Leaves oblong-ovate to lanceolate; branchlets glabrous. Exostema (p. 877). Leaves broad-elliptic to oblong-elliptic; branchlets villose. Guettarda (p. 879). _bb_ Leaves serrate (_often pinnate_). Lyonothamnus (p. 378). _aa_ Leaves without stipules. Petioles biglandular; leaves obtuse or emarginate, 1½′—2½′ long. Laguncularia (p. 767). Petioles without glands. Leaves furnished below with small dark glands, slightly aromatic; petioles short. Leaves oblong to oblong-ovate and acuminate or elliptic and bluntly short-pointed. Calyptranthes (p. 769). Leaves ovate, obovate or elliptic. Eugenia (p. 770). Leaves without glands. Leaves green and glabrous below. Leaves obtuse or emarginate at apex (_rarely alternate_), 1′—1½′ long. Torrubia (p. 341). Leaves acute, acuminate, or sometimes rounded or emarginate, 3′—5′ long. Leaves distinctly veined. Citharexylon (p. 864). Leaves obscurely veined. Osmanthus (p. 856). Leaves hoary tomentulose or scurfy below. Leaves strongly 3-nerved, acuminate, densely scurfy below. Tetrazygia (p. 776). Leaves penniveined, rounded or acute at apex, hoary tomentulose below. Avicennia (p. 865).

** Leaves deciduous. _a_ Leaves without lobes. _b_ Leaves serrate. Winter-buds with several opposite outer scales. Leaves puberulous below, closely and finely serrate; axillary buds solitary. Evonymus (p. 675). Leaves glabrous below, remotely crenate-serrulate; axillary buds several, superposed. Forestiera (p. 853). Winter-buds enclosed in 2 large opposite scales. Viburnum (p. 886). _bb_ Leaves entire. _c_ Leaves without stipules. Leaves suborbicular or elliptic to oblong. Leaves rounded or acutish at apex, 1′—2′ long, occasionally 3-foliolate, glabrous; branchlets quadrangular. Fraxinus anomala (p. 837). Leaves acuminate or acute at apex, 3′—4′ long. Leaf-scars connected by a transverse line, with 3 bundle-traces; branchlets slender, appressed-pubescent. Cornus (p. 785). Leaf-scars not connected, with 1 bundle-trace; branchlets stout, villose, puberulous or glabrous. Chionanthus (p. 855). Leaves broad-ovate, cordate, acuminate, 5′—12′ long, on long petioles. Catalpa (p. 870). Leaves linear to linear-lanceolate, short-stalked or sessile (_sometimes alternate_). Chilopsis (p. 869). _cc_ Leaves with persistent stipules, entire. Leaves oval or ovate; winter-buds resinous, the terminal up to ½′ in length. Pinckneya (p. 876). Leaves ovate to lanceolate; winter-buds minute. Cephalanthus (p. 878). _aa_ Leaves palmately lobed. Acer (p. 681).

2. Leaves Compound.

_a_ Leaves persistent, with stipules. Leaves equally pinnate; leaflets entire. Guaiacum (p. 630). Leaves unequally pinnately parted into 3—8 linear-lanceolate segments (_sometimes entire_). Lyonothamnus (p. 378). Leaves trifoliate. Leaflets stalked. Amyris (p. 640). Leaflets sessile. Helietta (p. 637). _aa_ Leaves deciduous. Leaves unequally pinnate or trifoliate. Leaflets crenate-serrate or entire, the veins arching within the margins; stipules wanting; winter-buds with several opposite scales. Fraxinus (p. 833). Leaflets sharply or incisely serrate, the primary veins extending to the teeth. Leaflets 3—7, incisely serrate; stipules present; winter-buds with 1 pair of obtuse outer scales. Acer Negundo (p. 699). Leaflets 5—9, sharply serrate; stipules present; winter-buds with many opposite acute scales; pith thick. Sambucus (p. 882). Leaves digitate, with 5—7, sharply serrate leaflets; terminal buds large. Æsculus (p. 702).

B. LEAVES ALTERNATE.

1. Leaves Simple. (2, see p. xxiv).

* Leaves persistent. (** see p. xxii).