Structure. 41 



( neglecting some hybrids), except in breaking out from the resting tuber. 

 N.fennica may rarely fork, as one of our specimens shows. The Lotos 

 and Hydrocallis species, however, give rise more or less freely to buds 

 from the lower part of the stem, and these develop into young plants 

 entangled among the roots and leaves of the parent. On the approach 

 of winter or the dry season, these lateral shoots harden off into resting 

 tubers for the perennation of the plant. Tubers thus produced (in 

 N, lotus) are very irregular in shape (Fig. 14 g), appearing knotty and 

 gnarly, but they still show in their lower half a smooth surface, and on 

 the upper parts a dense growth of long protective hairs intermingled 

 with remains of dead petioles. A remarkable development of lateral 

 shoots occurs in N. mexicana. Long stolons originate from the lower part 

 of the stem, even in very young plants, and run horizontally just beneath 

 the surface of the mud to form a new plant at a distance of 15 to 60 cm. 

 from the parent. No sooner has the young member established a few 

 roots and leaves than it in turn sends out runners, and so on. Three 

 or more such runners may be found attached to a single plant. Their 

 minuter details will be described in another place. In autumn the ends 

 of these runners develop a peculiar form of perennating stem (Fig. 15); 

 it consists of an axis 1 to 1.6 cm. long and 0.48 cm. in diameter lying 

 horizontally or obliquely in the soil ; on its upper surface is a continuous 

 row of 3 to 6 small leaf buds, while from the under surface depends a 

 bunch of thick, swollen, starch-laden roots 1 to 3.5 cm. long and 0.3 to 

 0.6 cm. in diameter ; these lie crowded over each other somewhat in 

 rows like bananas on a bunch ; at the tip of each a flattened and dis- 

 tended root-cap remains. 



A last type of stem exhibited by Nymphaea is that produced from 

 resting tubers when they resume growth. From the center of the upper 

 end of the tuber, in apocarpous species, a short, smooth, white stem 

 (stolon), 0.16 to 0.3 cm. in diameter, rises a centimeter or so, and at its 

 summit a tuft of leaves and roots is formed ; this may now be broken off 

 and will grow into a perfect plant, while the tuber will repeat the process, 

 if strong enough, as many as 8 or 10 times (N. flavo-virens and hybrids). 

 In Lotos species a much greater area of the tuber, in fact nearly all of its 

 upper surface, develops a very large number of tiny shoots, crowded all 

 over it. One, two, three or four of these start forward at nearly the same 

 time and each develops a long internode 1.2 to 8 or 10 cm. in length a 

 smooth, slender, white or reddish, often much curved stolon 0.16 to 0.3 cm. 

 in diameter bearing a simple lanceolate or subulate bract 0.6 to 2.5 cm. 



