98 RHAMNACEAE 



2. Leaves opposite or 4-ranked. 3. 



Leaves alternate. R. fallax. 



3. Branches often pungently tipped. R. cathartica. 

 Unarmed. R. lanceolata. 



3. Leaves glabrous, small (50 mm.), 4-ranked. R. Frangula. 

 Leaves longer, 5-ranked. 4. 



4. Peduncle shorter than petiole. R. caroliniana. 

 Peduncle longer. (Cascara sagrada). R. Purshiana. 



HOVENIA. Honey Tree. 



Deciduous unarmed trees with fine-grained wood; slender 

 zig-zag twigs; relatively large round homogeneous pith; alter- 

 nate somewhat raised rounded-heart-shaped leaf -scars with 3 

 bundle-traces; no stipule-scars; alternate superposed ovoid 

 buds with few exposed scales; simple palmately veined finely 

 toothed ovate stalked leaves; small perfect greenish flowers; 

 and small round 3-seeded dry fruits slender-stalked on fleshy 

 forking red axillary branches. 

 Twigs and buds hairy or glabrescent. H. dulcis. 



PALIURUS. Jerusalem Thorn. 



Deciduous shrubs or small trees with hard brownish wood; 

 very slender zig-zag terete twigs; small roundish pith; alter- 

 nate 2-ranked half-round somewhat raised minute leaf-scars 

 with 3 usually confluent bundle-traces; small stipules some of 

 them transformed into spines, one of each pair often straight 

 and the other curved; small sessile ovoid buds with about 3 

 exposed scales; small elliptical nearly entire petioled leaves; 

 small yellowish perfect polypetalous flowers in small axillary 

 clusters; and rather large indehiscent hat-shaped dry winged 

 fruit. 



Leaves 3-nerved, serrulate or oblique. P. Spina-Christi. 



ZIZPYPHUS. Jujube. 



Deciduous (or in warm countries evergreen) shrubs or 

 small trees with firm pale wood with minute diffused ducts 

 and very fine and close medullary rays; rather slender terete 

 twigs; more or less angular continuous or spongy pith; alter- 



