554 MISC. PUBLICATION 423, U. S. DEPT. OF AGRICULTURE 

 2. DODONAEA. Hopbush 



Shrub, with viscid foliage; leaves simple, short-petioled, the blades 

 narrow, entire, linear to oblanceolate ; flowers yellowish, in small lateral 

 corymbs, apetalous; fruits very conspicuous, dry, with 2 to 4 broad 

 wings. 



Sometimes called switchsorrel. The glutinous leaves and the bark 

 have been used to treat various diseases. The attractive winged fruits 

 have been used as a substitute for hops. In Arizona a shrub up to 

 3.5 m. (12 feet) high. The plant appears to be unpalatable to livestock 

 and tends to increase on overstocked ranges. It is doubtless harmful, 

 as it contains saponin and is used in some countries as a fish poison. 



1. Dodonaea viscosa Jacq., Enum. PL Carib. 19. 1760. 



Southern Yavapai County to Cochise and Pima Counties, 2,000 to 

 4,000 feet, fairly common on dry rocky slopes and in canyons, often 

 on limestone, frequently with Simmondsia and Fouquieria, February 

 to October. Widely distributed in the warmer parts of the world. 



Arizona possesses only the narrow-leaved form, var. angustifolia 

 (L. f.) Benth. (D. arizonica A. Nels.). 



71. RHAMNACEAE. Buckthorn family 



Shrubs or small trees; leaves simple; flowers small, perfect or uni- 

 sexual, regular or nearly so, 4- or 5-merous, with or without petals, 

 with a disk in the calyx throat on which the stamens often are borne; 

 ovary 2- or 3-celled, superior or partly inferior. 



Most of these plants are browsed by domestic animals and deer. 



Key to the genera 



1. Fruits drupelike, with a single stone, this 1- or 2-celled; leaves alternate or 



fascicled; branches rigid, often spiny; ovary superior 1. Condalia. 



1. Fruits capsular or drupelike, with 2 to 4 separate or nearly separate stones (2). 

 2. Ovary superior (free from the calyx) ; fruit drupelike, more or less fleshy, the 

 cells indehiscent (3). . 

 3. Flowers sessile, in small panicles terminating the branchlets; petals pres- 

 ent; style 3-lobed 2. Sageretia. 



3. Flowers pedicellate, axillary, solitary or in small clusters; petals sometimes 



absent; style 2-lobed _ 3. Rhamnus. 



2. Ovary partly inferior (adnate below to the calyx) ; fruit capsulelike, dry at 

 maturity, the cells dehiscent (4). 



4. Calyx lobes petaloid; petals white, bluish, or lavender pink, long-clawed, 



hooded, often spreading away from the stamens 4. Ceanothus. 



4. Calyx lobes not petaloid; petals greenish or yellowish, short-clawed, 

 standing close to the stamens 5. Colubrina. 



1. CONDALIA 



Shrubs or small trees with rigid, usually spiny branches; leaves 

 alternate or fascicled, pinnately veined, often conspicuously so; flowers 

 axillary, in small fascicles or solitary; petals present or absent; ovary 

 superior; fruit a drupe with one stone. 



Key to the species 



1. Leaves elliptic to ovate, commonly at least 5 mm. wide, entire or dentate, the 

 veins (except the midvein) slender and rather inconspicuous; petals present; 

 fruit globose or nearly so, not beaked, at maturity dark blue with a bloom, 

 6 to 8 mm. in diameter; spines numerous, stout, divaricate or slightly 

 decurved 1. C. lycioides. 



