i6o 



THE WATERLILIES. 



leathery ; margin coarsely and irregularly sinuate-dentate, the teeth mostly angular and 

 obtuse, the larger sinuses as much as 1.3 cm. deep. Upper surface green, faintly brown- 

 blotched when young ; under surface suffused violet or even dark purple ; veins promi- 

 nent, primary nerves 10 to 12 on each side ; length of principal area : radius of leaf 

 = i: i.i to 1.7. Sinus, depth: length of leaf = i : 2 to 2.9, margins convex, more or 

 less widely overlapping, or oftener touching and both curled upward, forming a raised 

 keel 1.3 to 2.5 cm. high in place of the sinus; angles forming an acute tooth in series 

 with the marginal serration of the leaf, but lying within the circle described by the 

 leaf-margin. Stipules fused at base, long-lanceolate, tapering, acuminate. 



Rhizome ovate or cylindric-ovate, rather stout, protected by long hairs at summit, 

 smooth below when dry ; producing no offsets during vegetative season. 



MEASUREMENTS OF LEAVES. 



GEOGRAPHIC DISTRIBUTION. The island and town of Zanzibar, in permanent rain- 

 pools (Caspary 1877). 



NOTES. Seeds of this species were received by Caspary from J. M. Hildebrandt 

 in the middle of April, 1874, packed in chalk. Planted in water at 22 R., they germi- 

 nated freely in about two months, and in 1875 seven strong plants came into flower; 

 these were the types on which the species was established. In herbaria, however, it is 

 almost indistinguishable from N. capensis, and they form fertile crosses; we have there- 

 fore reduced this one to varietal rank. It hybridizes readily with all the members of 

 the Brachyceras group. 



Seeds developed late in the season will withstand the winters of Philadelphia and 

 vicinity, germinate spontaneously, and form blooming plants the following summer; 

 but the flowers are produced too late to ripen seed for the succeeding season. The 

 same is true of N. caerulea, whose seeds have lain two years before developing plants. 

 Planted in small pots, N. zanzibariensis will produce perfect flowers of any desired size 

 down to 2.5 to 3 cm. in diameter. 



