DIV. II 



ANGIOSPERMAE 



657 



Family.,,4. Aceraceae. Include Maples and Sycamores with their character- 

 istically winged fruits (Fig. 684). 



Family 5. Hippocastanaceae. The Horse-chestnut. Aesculus hippocastanum. 



Order 17. Frang-ulinae 



This order is characterised 

 stamens and the intrastaminal 

 disc. 



Family 1. Rhamnaeeae. 

 The only native genus of this 

 family, which is distributed in 

 the tropics, is Rhamnus. 



by the single whorl of antipetalous 

 B O 



Rh. Frangula (Figs. 685 B, 686, 

 687), the Berry-bearing Alder, is a 

 shrub with alternate, entire leaves 

 provided with small stipules. The 

 flowers are solitary or in groups in 

 the axils of the leaves ; pentamerous, 

 with two carpels. The floral receptacle forms 



FIG. 635. Floral diagrams of A, Rhamnus cathartica 

 (represented as hermaphrodite), and B, Rh. 

 Frangula. (After EICHLER.) 



a cup-shaped disc. Two (less 

 commonly three) carpels ; stigma 

 undivided. Fruit, a drupe with 

 two or three seeds. Rh. cathar- 

 ticus has usually spiny branches 

 bearing opposite leaves with 

 serrate margins. Flowers tetra- 

 rnerous throughout (Fig. 685 A), 

 dioecious by suppression - of 

 stamens or carpels ; female flower 

 with four free styles and a four- 

 seeded drupe. Seeds with a 

 dorsal raphe. Colletia spinosa 



FIG. 686. Rhamnus Frangula (nat. size). Flowering 

 branch and portion of a branch bearing fruits. 



FIG. 687. Rhamn us Frangula. Flower 

 cut through longitudinally, a, Re- 

 ceptacle ; b, calyx ; c, petal ; d, a 

 stamen; e, pistil (magnified). (After 

 BERO and SCHMIDT.) 



and C. cru-ciata are leafless South American shrubs ; the thorns of the former 

 are cylindrical, those of the latter flattened laterally. 



2U 



