CH. Ill] WATERLILY RHIZOMES 25 



be seen as rudiments and at r^ as scars, while numerous groups 

 of three mature roots are also shown (e.g. r^: Fig. 10 5 repre- 

 sents such a group in further detail. The root system is very- 

 elaborate, since the adventitious roots bear branches (Fig. loB) 

 which themselves branch again (Fig. 10 C). At the apex arises 

 the rosette of leaves and flower stalks belonging to the current 

 year, and lateral buds may also be produced (Fig. 10^, /.<^.). 

 The rhizome may be as thick as a man's arm. 



'f^^ 



Fig. 10. Nymphaea liitea, L. June 30, 1913. A, Part of old rhizome, bases, only, 

 of leaves indicated and all root-branches omitted ; p.s. = scar of peduncle; l.s. = leaf- 

 scar; r^, group of three rudimentary roots arising from a leaf base; yj, correspond- 

 ing group of three roots fully developed; r^, scars of three dead roots; ap, apical 

 region of rhizome; l.b., lateral branch bearing leaves of submerged type only. 

 B and C, roots in greater detail, placed horizontallj^ to save space. B, three young 

 roots from a single leaf-base to show laterals ; C, part of an old root to show branch- 

 ing of laterals. {\ nat. size.) [A. A.] 



Castalia alba ^, Greene, has a shorter rhizome with the leaves 

 crowded in the apical region (Fig. 1 1 yf, p. 26). When the older 

 leaves and flower stalks have been removed to expose the apical 

 bud, the most remarkable feature revealed is the occurrence of 

 large membranous stipules, one of which accompanies each 

 young leaf adaxially; each appears to represent a fused pair 

 (5/. in Fig. 1 1 5, C, D). A larger number of roots is associated 

 with each leaf than in the case of the Yellow Waterlily. These 



1 = Nymphaea alba, L, 



