518 DICOTYLEDONES. 



hypogynoiis, ^ , perfect with gamopetalous corolla, but most fre- 

 quently irregular (medianly zygomorphic, except Solanacece), the 

 corolla being bilabiate (divided into a posterior part of two lobes 

 and an anterior part of three lobes), and the stamens 4, didynamous 

 (the posterior being suppressed). The ovary has 2 loculi (only 1 

 in Utriculariacece, Gesneriacece, Orobanche) the placenta in the 

 first-named orders (17) is most frequently very thick, and bears a 

 great many ovules (Figs. 554, 555, 557, 562) ; the number of ovules 

 in the last orders (8-9) is considerably reduced (Fig. 570). 



Special mention may be made of the apparently 4-merous 

 flower which is found, e.g. in Veronica and Plantago (Figs. 567, 

 562(7, 570, 571), and which arises from the typical 5-merous 

 flower by the suppression of the posterior sepal and the posterior 

 stamen, and by the union of the two posterior petals into one. 

 Terminal flowers very seldom occur on the main axis, and would 

 not harmonise well with the very irregular form of the flower. 

 When they do occur, they are, as a rule, " peloric," i.e. regular (in 

 Linaria vulgaris two kinds of peloric flowers occur, one with 5 

 spurs, and one without spurs). The halves of the anthers are often 

 divided as far as the base, and laterally so widely separated from 

 each other as to assume an almost straight line (Figs. 563, 564). 

 There is generally a nectary (" disc ") round the base of the ovary, 

 often 5-lobed (or divided into free glands). A common vegetative 

 characteristic is the absence of stipules. 



The 9 orders of the Personatae are : 1, Solanacese ; 2, Nolanaceae ; 3, Scrophu- 

 lariaceae ; 4, Utriculariaceas ; 5, Gesneriaceae ; 6, Bignoniaceae ; 7, Pedaliaceas ; 

 S, Acanthaceas ; 9, Plantaginaceae. 



Order 1. Solanacese. The flower (Figs. 554, 555, 559) is 

 hypogynous, regular (zygomorphic in Hyoscyamiis}, $, and gamo- 

 petalous, with S5, P5 (most frequently 

 imbricate or valvate), A5, G2, the 2 car- 

 pels being placed obliquely (Fig. 554) ; 

 the bilocular ovary has a very thick axile 

 placenta (Figs. 554, 555 H, 557), which 

 extends almost as far as the wall of the 

 ovary. The fruit is a capsule or berry; 

 the seeds are more or less reniform, and 

 the embryo is curved (rarely straight), in 



Fi0.654_Dia~gramofP*tuma. ' a ^^ endosperm (Figs. 555 F, G-, 



561). Both arborescent and herbaceous 



forms are found in the order; leaves scattered without stipules, 



