D1COTYLEDONES : POLYPETALJI : THALAMIFLOfLE. 



607 



and which throws up petiolate foliage-leaves, and bracteolate peduncles each 

 bearing a single flower : V. odorata has runners, but hirta and collina have 

 none: in others, as V. canina, the Dog-Violet, the main stem is above ground 

 and bears the foliage-leaves : in V. mirabilis these two forms are so combined 

 that, in the spring, flowers are developed from the rhizome which have large blue 

 petals but are always sterile ; it is not till later that inconspicuous (cleistoga- 

 mous, p. 453) flowers with minute petals appear on the leafy stem, and these 

 only are fertile : in V. tricolor and its allies the stipules are leafy and 

 pinnatifid. 



Cohort V. Sarraceniales. Flowers regular, generally actino- 

 morphic, sometimes monochlamydeous : stamens often numerous, 

 ovary syncarpous, uni- or multi-locular ; placentation various; 

 seeds many, with endosperm ; 

 leaves adapted in various ways 

 for the capture of insects. 



Order 1. SARRACENIACEJ;. 

 Flowers $ , usually dichlamy- 

 deous, hemicyclic : stamens 15 

 or more : ovary either unilocular 

 and more or less chambered, or 

 3- or 5-looular ; placentation pa- 

 rietal or axile : leaves pitchered 

 (Fig. 410). 



This order includes the three her- 

 baceous genera Sarracenia, Darling- 

 tonia, and Heliamphora. The two 

 former have pentamerous dichlamy- 

 deous flowers, each borne singly on a 

 peduncle ; the sepals and petals are 

 in f arrangement, and the stamens 

 are indefinite in Sarracenia and 15 in 

 Darlingtonia ; carpels 5, antisepalous 

 in Sarracenia, antipetalous in Dar- 

 lingtonia : they grow on moors and 

 marshes in North America. Heliam- 

 phora ^ ars its flowers in racemes ; 

 the flower has a simple petaloid peri- 

 anth, indefinite stamens, and a trilocular ovary; it is a native of British 

 Guiana. 



Order 2. NEPENTHACEJ:. Flowers dioecious, monochlamydeous, 

 tetramerous : stamens generally 4-16, coherent into a central 

 column : ovary quadrilocular, with axile or somewhat superficial 

 placentation: leaves pitchered (Fig. 37, p. 58). 



FIG. 410. Leaves and flowers of 

 cenia purpurea (|) : the leaf to the left has 

 been cut across. 



V. S. B. 



R R 



