BUTACEAE (RUE FAMILY) 537 



RUTACEAE (RuE FAMILY) 



Plants with simple or compound leaves, dotted with pellucid glands and 

 ili'inndiny with a pungent or bitter-aromatic acrid volatile oil, producing hypogy- 

 nons almost always regular 3-5-merous flowers, the stamens as many or twice 

 rt> mitny as the sepals (rarely more numerous) ; the 2-5 pistils separate or com- 

 bined into a compound ovary of as many cells, raised on a prolongation of the 

 receptacle (gynophore) or glandular disk. Embryo large, usually in fleshy 

 albumen. Styles commonly united or cohering. Fruit usually capsular. Leaves 

 in ours alternate. Stipules none. A large family, chiefly of the Old World 

 and the southern hemisphere. 



1. Zanthoxylum. Flowers dioecious; ovaries 3-5, separate, forming fleshy pods. 



2. Ptelea. Flowers polygamous ; ovary 2-celled, forming a samara, like that of Elm. 

 8. Ruta. Flowers perfect ; ovary 4-5-lobed, forming a several-seeded capsule. 



1. ZANTH6XYLUM L. PRICKLY ASH 



Flowers dioecious. Sepals 4 or 5, obsolete in one species. Petals 4 or 5, 

 imbricated in the bud. Stamens 4 or 5 in the sterile flowers, alternate with the 

 petals. Pistils 2-5, separate, but their styles conniving or slightly united. Pods 

 thick and fleshy, 2-valved, 1-2-seeded. Seed-coat crustaceous, black, smooth 

 and shining. Embryo straight, with broad cotyledons. Shrubs or trees, with 

 mostly pinnate leaves, the stems and often the leafstalks prickly. Flowers small, 

 greenish or whitish. (From av06s, yellow, and &\ov, wood.) 



1. Z. americanum Mill. (NORTHERN P., TOOTHACHE-TREE.) Leaves and 

 flowers in sessile axillary umbellate clusters ; leaflets 2-4 pairs and an odd one, 

 ovate-oblong, downy when young ; calyx none ; petals 4-6 ; pistils 3-5, with 

 slender styles; pods short-stalked. (Xanthoxylum of auth.). Rocky woods 

 and river-banks, w. Que. to Minn., s. to Va., Ky., Mo., and e. Kan. Apr, May. 

 An aromatic shrub, with yellowish-green flowers appearing before the leaves. 



2. Z. Clava-H6rculis L. (SOUTHERN P.) Glabrous ; leaflets 3-8 pairs and 

 an odd one, ovate or ovate-lanceolate, oblique, shining above; flowers in an 

 ample terminal cyme ; sepals and petals 5 ; pistils 2-3, with short styles ; pods 

 sessile. (Z. carolinianum Lam.) Sandy coast of Va., and southw. June. 

 A small tree with very sharp prickles. 



2. PTELEA L. SHRUBBY TREFOIL. HOP TREE 



Flowers polygamous. Sepals 3-6. Petals 3-5, imbricated in the bud. Sta- 

 mens as many. Ovary 2-celled ; style short ; stigmas 2. Fruit a 2-celled and 

 2-seeded samara, winged all round, nearly orbicular. Shrubs, with 3-foliolate 

 leaves, and greenish-white small flowers in compound terminal cymes. (The 

 Greek name of the Elm, here applied to a genus with similar fruit. ) 



1. P. trifoliata L. Leaflets ovate, pointed, downy when young. Rocky 

 places, L. I. to Ont., Minn., and southw. ; cultivated and often established else- 

 where. June. A tall shrub. Fruit bitter, used as a substitute for hops. Odor 

 of the flowers disagreeable. 



Var. m611is T. & G. Branchlets, petioles, and both surfaces of the somewhat 

 thickish leaflets densely and permanently velvety. Shore of L. Mich., Sauga- 

 tuck, Mich. ( Wheeler) ; also Tex., etc. 



3. RtTTA [Tourn.] L. RUB 



Flowers perfect, 4-5-merous. Calyx persistent. Petals yellow, the sides 

 and apex strongly inrolled, the margin denticulate or ciliate-dentate. Stamens 

 8-10, inserted about the base of the torus, the alternate ones smaller. Capsule 

 4-5-lobed, dehiscent at the summit, many-seeded. Heavy-scented herbs or 



