9 2 



THE WATERLILIES. 



three cells from the micropyle. At the hilum the thick-walled cells of the 

 inner seed coat are rounder and more closely packed than elsewhere. 



Based on the examination of the seeds of about twenty species of 

 Nymphaea, Weberbauer distinguished four types of testa, as follows: 



(1) Surface bare, smooth, and shining: IV. alba, Candida, tuberosa, odorata. 



(2) Bare, with longitudinal ridges ; adjacent edges of rows of cells are 



alternately raised up or level ; the ridges may be interrupted at 

 middle of seed (IV. rubra (Fig. 42, a], pubescens]. 



(4) 



FIG. 42. Sections of outer cell layer of testa: a, N. rubra; b, N.flavii- 

 vireg (" N. gracllis" Welierb.) ; c, N. stellata. After Weberbauer. 



(3) The seed bears longitudinal rows of hairs in the position of the ridges 

 of the second type ; the rows may be similarly interrupted (A^. blanda, 

 amazonum, gigantca, caerulca, stcllata (Fig. 42, r), capensis, amp/a, 

 madagascariensis); N. lotus, tlicr mails, and dcntata are only slightly 

 hairy and show transitions to the second type. 



Both longitudinal and transverse cell walls have short papillar out- 

 growths ( N. flavo-vircns, Fig. 42, /;). 



Differences occur in the degree of flattening of the outer cells and 

 thickening of the walls, as also in the number of hairs and character of 

 the surface under them. In N. thermalis the amount of thickening is less 

 than in other Lotos species, and in N. gigantea the outer walls of the 

 cells are scarcely thicker than the lateral and inner walls. In N. rubro 

 the cells are but little compressed. A^. amazomuii has a dull, roughened 

 surface beneath the hairs, but in "JV. blanda " (probably N. rudgeana) this 

 is very smooth and shiny and the hairs are bent at the tip. N. ampla 



