CHAPTER VI. 



DISTRIBUTION. 



On account of their aquatic habits, requiring still water, mostly fresh, 

 and enduring comparatively little sedimentation, the areas in which water- 

 lilies occur are at times scattered. They are found here and there 

 almost all over the world. New Zealand and the Pacific Slope of North 

 America have no representatives of the genus Nymphaea. The Castalia 

 group is wholly restricted to the northern hemisphere, and Brachyceras to 

 the tropics and subtropical regions, but both are found all round the globe. 

 Lotos is mostly tropical, and is restricted to the Eastern Hemisphere, 

 where it ranges from Sierra Leone and Senegambia to the Philippines, 

 while Hydrocallis is native to the tropics of the New World. N. gigantea 

 occurs only in tropical Australia and New Guinea. 



Nymphaea is, generally speaking, a genus of the low lands. The 

 Atlantic coastal plain of North America is the home of N. odorata, and 

 N. flai<a is found in brackish water in the Little River, Florida. N. oxy- 

 petala was collected at Guayaquil, Ecuador. In the West Indies, the Phil- 

 ippines, and Australia they occur along the coastal swamps, and at river 

 mouths. The delta of the Nile is a favorite haunt of TV. lotus and cacrulea. 

 On the other hand, both of these species are reported from central Africa, 

 and similar ones from the interior of India. IV. tetragona and alba ascend 

 1500 meters in Kashmir, and our own N. odorata ascends 600 meters 

 in the eastern United States. 



The distribution ol single species is often very wide, and the varia- 

 tions correspondingly great, insomuch that the limitation of species is, in 

 our present state of knowledge, more than usually arbitrary. Careful 

 studies of plants from many localities under cultivation and hybridization 

 are needed to place this branch of our subject on a better footing. 

 Another uncertain feature is the range of the Hydrocallis species. Their 

 native countries are all so little known botanically that most of them must 

 be left out of account in these generalizations. Outside of the Hydro- 

 callis group, probably the most restricted species is N. mexuana, known 

 only from Florida, Texas and Mexico. N. tetragona, on the other hand, 



213 



