SECT. II PHANEROGAMIA 609 



Family 1. Rhamnaceae. — The only native genus of this family, 

 which is distributed in the tropics, is Bhamnus. 



Rh. Frmujula (Fig.s. 617 B, 619), the Beny-bearing Alder, is a shrub with 

 alternate, entire leaves provided with small stipules. The Howers are solitary or 

 in groups in the axils of the leaves ; pentameious, with two carpels. The floral 

 receptacle forms a cup-shaped disc. Two (less commonly three) carpels ; stigma 

 undivided. Fruit, a drupe with two or three seeds. The wood was formerly used 

 as a source of charcoal for the manufacture of gunpowder. Eh. catharticus has 

 usually spiny branches bearing opposite leaves with serrate margins. Flowers 

 tetramerous throughout (Fig. 617 A), dioecious by suppression of stamens or 

 carpels ; female flower with four free styles and a four-seeded drupe. Seeds Mith 

 a dorsal furrow. CoUctia sjnnosa and C. cruciata are leafless South American 

 shrubs ; the thorns of the former are cylindrical, those of the latter flattened 

 laterally. 



Official, — Rhainmis purshianus yields cascaea sagrada or rhamni 



PURSHIANI CORTEX. 



Family 2. Vitaeeae. — Shrubby plants climbing by means of 

 tendrils ; leaves palmately lobed or divided. Flowers hypogynous. 

 Ovary composed of 2-4 carpels and with a corresponding number of 

 loculi. Two ovules in each loculus. Disc often consisting of separate 

 glands (Figs. 620, 621). An almost exclusively tropical and sub- 

 tropical family. 



Important Genera. — Vitis, climbing shrubs of the northern hemisphere. 

 Vitis vinifera, the Grape Vine, is a cultivated plant with numerous races and 

 varieties. The tendrils correspond to shoots and stand opposite to the leaves ; 

 they are at first terminal, but become displaced to one side by the development of 

 the axillary shoot. The whole shoot is thus a sympodium. The original relation 

 between the tendrils and the axillary shoots, which are both recognisable at the 

 growing point, cannot be completely followed in the ontogeny. The inflorescence 

 is a panicle taking the place of a tendril ; intermediate forms between inflorescences 

 and tendrils are of frequent occurrence. Calyx only represented by a small rim ; 

 Corolla thrown ofl' when the flower opens. Currants are the seedless fruits of Vitis 

 vinifera, var. apyrena. Species of Quinaria distributed in North America and 

 Asia go by the name of Wild Vines ; some of them have tendrils with adhesive 

 disc (Fig. 29 and p. 318). Cissus is a large, exclusively tropical genus. 



Official. — Uvae, Raisins from Vitis vinifera. 



Order 18. Saxifraglnae 



Herbs or woody plants of very diverse habit, with actino- 

 morphic, pentamerous flowers. Androecium usually obdiplostemonous. 

 Carpels 2-5, free or coherent. Flowers hyjDogynous, perigynous, or 

 epigjmous. 



The family of the Podostemonaceae (=") may be included in this order. The 

 vegetative and reproductive organs of these plants are peculiarly modified in 

 relation to their mode of life, ana the situations they occujiy in the most rapid 

 currents and waterfalls of rivers and streams in the tropics. 



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