PERSONATE. 



519 



but with variously formed laminge (always penuingrved). A 

 peculiar leaf-arrangement is found in many species, viz. t'ie leaves 

 are borne in pairs, a large and a smaller one together ; these pairs 

 stand in 2 rows, and the flowers are then situated between the 

 individual leaves in each pair, apparently not in a leaf axil. The 

 inflorescences are frequently unipared scorpioid cym.33 without 

 floral-leaves. 



PIG. 555. Atropa belladonna: A is reduced. 



Zygomorphic flowers occur, aiid thus form a transition to the closely allied 

 Hcrophulariacese ; the zygomorphy sometimes shows itself only in the relative 

 length of the stamens, sometimes also in the corolla (Hyoscyamus).Nicandra 

 is 5-merous throughout all the whorls. The peculiar relative leaf -arrangement 

 in this order occurs from sympodial branching and displacement. The most 

 simple is, e.g. Datura (Fig. 556 A) ; each shoot-generation in the floral parts of 

 the plant has only 2 foliage-leaves (/ l and / 2 ), and then terminates in a flower ; 

 the axillary buds of both the foliage-leaves are developed and form a dichasium, 

 but since the leaves are displaced on their axillary-shoots as far, or almost as 

 far, as the first leaf of these axillary-shoots, the flowers are borne singly on the 

 dichasial branches, and all the branches appear to be without subtending leaves 

 (Shoot I is white, II shaded, III white, etc., diagram A). Scopolia and others 

 (Fig. 556 B) differ in that the lowest and smallest (f l ) of the two leaves on 

 each shoot is barren, and is therefore not displaced ; but the upper one (the 

 second bracteole, /*) is displaced as in the first instance, and consequently it 

 assumes a position near the first leaf (the shaded leaf/' 2 of shoot I being placed 

 near the white leaf f 1 of shoot II, etc.,) of the next youngest shoot-generation, 



