580 TREES OF NORTH AMERICA 



a short stout stalk. Fruit broadly obovate, ' long, % wide, bright orange color, 

 opening at maturity by the splitting of the thick rather fleshy valves; seeds black, 

 with a thick fleshy scarlet aril-like outer coat. 



A gnarled round-headed tree, sometimes 25-30 high, with a short stout trunk 

 occasionally 2^-3 iu diameter, slender pendulous branches, and branchlets con- 

 spicuously enlarged at the nodes, slightly angled, pubescent at first, becoming in 



their second year glabrous, nearly white, and roughened by numerous small ex- 

 crescences. Bark of the trunk rarely more than ^' thick, separating on the surface 

 into thin white scales. Wood dark green or yellow-brown, with thin clear yellow 

 sapwood. 



Distribution. Keys of southern Florida from Key West eastward; on the 

 Bahama Islands and on several of the Antilles. 



XXIV. 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 panicu- 

 late or corymbose cymes; calyx 3-5-lobed, the lobes more or less united at 

 the base, imbricated in the bud ; petals 3-5, imbricated 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 a cap- 

 sule, samara, or drupe. 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 vulgaris, Risso, the Bitter-sweet Orange, a native of 

 Asia, has long been naturalized in the peninsula of Florida, where other spe- 

 cies of this genus have escaped from cultivation and are now growing spon- 

 taneously. 



