RUTACEyE 633 



out the year on slender puberulous pedicels \' to nearly \' long from the axils of acuminate 

 caducous bracts a third longer than their acuminate bractlets, in terminal 5-12-flowered 

 erect racemes f'-l^' in length; calyx cup-shaped, persistent under the fruit, with short 

 nearly triangular lobes much shorter than the white petals turning yellow, pink or rose 

 color; styles elongated and persistent on the fruit. Fruit subglobose, greenish, about j' 

 in diameter, the flesh thin and dry; stone woody, rugose, thick-walled, lustrous on the 

 inner surface; seed ovoid, acute, filling the cavity of the stone, pale yellow. 



A small tree, rarely 20 high with a trunk 10' in diameter, covered with pale bark, 

 spreading branches forming a flat-topped head and slender terete pale gray branchlets; 

 more often a many-stemmed shrub. 



Distribution. Florida, in sandy soil on the Everglade Keys, Dade County, and on 

 several of the southern keys; on the Bahamas and many of the Antilles; in Florida ar- 

 borescent on Long Key in the Everglades, and on Big Pine Key. 



XXVI. RUTACE^;. 



Trees or shrubs, abounding in a pungent or bitter aromatic volatile oil, with simple or 

 compound usually glandular-punctate leaves, without stipules or rarely with stipular 

 spines. Flowers regular, perfect or unisexual, in paniculate or corymbose cymes; calyx 

 3-5-lobed, the lobes more or less united at base, imbricated in the bud; petals 3-5, imbri- 

 cated in the bud; stamens as many or twice as many as the petals; filaments distinct or 

 united below; anthers introrse, 2-celled, the cells opening longitudinally; pistils 1-4, sep- 

 arate or united into a compound ovary sessile or stipitate on a glandular disk; styles mostly 

 united; ovules usually 2 in each cell of the ovary, pendulous, anatropous or amphitropous; 

 raphe ventral; micropyle superior. Fruit of 2-valved carpels, a samara, drupe or capsule. 

 Seeds solitary or several; seed-coat bony or crustaceous, furrowed or punctate; embryo 

 axile in fleshy albumen; radicle short, superior. 



Of this large family, widely distributed over the warm and temperate parts of the earth's 

 surface, four genera only have arborescent representatives in the United States. Citrus 

 Aurantium L., the Bitter-sweet Orange, a native of Asia, has long been naturalized in the 

 peninsula of Florida, where other species of this genus have escaped from cultivation and 

 are now growing spontaneously. 



CONSPECTUS OF THE ARBORESCENT GENERA OF THE UNITED STATES. 



Fruit of 1-5, 2-valved 1-seeded carpels; flowers dioecious or polygamous. 1 . Xanthoxylum. 

 Fruit of 3 or 4-winged indehiscent 1-seeded carpels; flowers perfect. 2. Helietta. 



Fruit a winged samara; flowers polygamous. 3. Ptelea. 



Fruit a 1-seeded drupe; flowers perfect or polygamous. 4. Amyris. 



1. XANTHOXYLUM L. 

 ^ 



Trees or shrubs, with acrid aromatic bark, pellucid aromatic-punctate fruit and foliage, 

 scaly buds, and usually stipular spines. Leaves alternate, unequally or rarely equally 

 pinnate; leaflets generally opposite, often oblique at the base, entire or crenulate. Flowers 

 small, dioecious or polygamous, in axillary or terminal broad or contracted pedunculate 

 cymes; calyx and petals hypogynous; disk small or obscure; stamens as many as the petals 

 and alternate with them, hypogynous, effete, rudimentary or wanting in the female flower; 

 filaments filiform or subulate; pistils 1-5, oblique, raised on the summit of a fleshy gyno- 

 phore, connivent, sometimes slightly united below, rudimentary, simple or 2-5-parted in 

 the sterile flower; ovaries 1-celled; styles short and slender, more or less united toward the 

 summit; stigmas capitate; ovules collateral, pendulous from the inner angle of the cell. 

 Fruit of 1-5 coriaceous or fleshy 1-seeded carpels, broad-obovoid, sessile or stipitate, 

 ventrally dehiscent. Seed solitary oblong or globose, suspended on a slender funicle, often 



