I 



DICOTYLEDONES : POLYPETALiE : CALYCIFLOU^E. 627 



Order 1. PASsrFi'.ORACEiE. Flowers pentamerous, perigjnous, 

 sometimes dioecious ; between corolla and androecium there is a 

 so-called corona consisting of a number of filamentous appendages, 

 probably representing a disc (see p. 527) : the gyneeceum fre- 

 quently, and sometimes also the androecium, is elevated upon an 

 elongation of the axis (gynophore, or gonophore, p. 495) : stamens 

 five, often monadelphous, opposite to the sepals: ovary unilocular 

 with three parietal placentas : leaves palmate. Climbing plants, 

 with tendrils, each tendril being a lateral axillary branch, and 

 frequently the main axis of an inflorescence. 



Several species of Passiflora, the Passion-Flower, from tropical America, are 

 cultivated. 



Order 2. Papayace.e. Flowers diclinous, hypogynous : stamens 

 in two whorls : ovary usually unilocular with five parietal 

 placentae. 



Carica Pnpaija, the Papaw, is cultivated in the tropics on account of its 

 edible fruit : its latex is rich in proteolytic ferment (papain). 



Order 3. Begoniacej;. Affinity doubtful. Flowers diclinous; 

 perianth rarely heterochlamydeous : the ^ flowers have two 

 dimerous petaloid perianth- whorls, and indefinite stamens crowded 

 together : the ? flowers are epigynous ; the perianth consists of 

 five petaloid leaves; the ovary is usually trilocular, with numerous 

 anatropous ovules borne on axile placentee : fruit a capsule : leaves 

 often very large, usually oblique : inflorescence cymose, the (^ 

 flowers being terminal on the first branches, the ? terminal on 

 the last. 



Many species of Begonia, derived from the tropics, are cultivated as orua- 

 mental plants. 



Order 4. Cucurbitace^. Flowers diclinous or polygamous, often 

 irregular : corolla of five petals, often gamopetalous : stamens 

 epipetalous, five, but they frequently cohere, either in pairs, so 

 that there appear to be but three (Fig. 428, diagram), or all 

 completely into a single continuous ring (Cyclanthera) ; the 

 anthers are commonly long and sinuous : ovary inferior, unilocular, 

 becoming spuriously multilocular, with one or (more often) many 

 ovules; it is, however, often described as multilocular (usually 3) 

 with projecting axile placentae : fruit baccate, a pepo or a succu- 

 lent berry, often of great size, with a relatively thick and solid 



