40 



The Waterlilies. 



tubers are usually of an ellipsoid shape, or spheroidal in N. gigantea and 

 elegans (Fig. 14). They are of a brownish black color, smooth and 

 rounded in the lower half, but more or less acute above, because 

 the apical region is protected by a dense upward growth of long fine hairs 

 intermingled with dried and shriveled bases of petioles. These tubers 

 live through the dry season without injury, and begin growth again in 

 a characteristic manner on the return of sufficient moisture and heat. 

 Mature stems of the types under discussion are, like the tubers, of an 

 ellipsoid shape, and have grown in our Botanic Garden to a length of 



Fio. H. Tubers : a, N. amazonum ; b, b', N. gigantea, from two sides 90 degrees apart ; c, e', N. eapensis, two 

 specimens; d, a", N. elegans, two specimens; e, N. tanzibariensis rosea; f, N. lotus, seedling; g. If. lotus, 

 lateral tuber from mature plant. All natural size. 



20 cm., and a diameter of 10 cm. in N. rubra var., 12.7 by 7.5 cm. in 

 N. dentata, caerulea and zanzibariensis ; I have seen a resting tuber of 

 N. Mrs. C. W. Ward (N. flavo-virens X zanzibariensis rosea) in the Dreer 

 Nurseries which measured 21 cm. by 10 cm. All of these are of a 

 brownish black color. With us N. flava has not exceeded 7.6 cm. long 

 by 1.6 cm. broad, and has a yellowish color, but Mrs. Treat (1877) records 

 the length of an old caudex in the St. Johns River, Florida as 60 cm., and 

 diameter 10 cm. N. tetragona stem is rather slender, 7 to 12 cm. 

 long by 2.5 cm. in diameter, and is of a blackish color ; N. fennica is 

 similar in appearance but stouter, 10 cm. long by 3.75 cm. in diameter. 



No branching of the stem, that is, no development of vegetative 

 buds, occurs in N. tetragona, and none in any of the apocarpous species 



