PTERIDOGRAPHIA. 



Nephrolepis Roosevelt. — A new sport from Ne- 

 phrolepis exaltata or Bostvniensis has been registered 

 with the Society of American Florists under the title 

 given above. Fortunately the namer, thus far, has re- 

 frained from adding an i or two to the second word 

 and thus making it in the nature of a real specific 

 name. The great number of named forms of Nephro- 

 lepis that have recently appeared is simply added evi- 

 dence of the fact that all plants are variable. We are 

 inclined to take just as much stock in these Nephro- 

 lepis "species" as we do in a large number of the so- 

 called species of Selaginclla and Botrychium with 

 which the synonomy of these fern- worts has been in- 

 fested in recent years. 



Azolla and Mosquitoes. — The war that is being 

 waged on the mosquito pest has found a new ally in 

 the common water fern (Azolla Caroliniand). From 

 several sources come reports that when the surface of 

 the water is covered with a growth of this plant, mos- 

 quitos cease to breed in it. It does not seem to be 

 definitely known how the plant affects the mosquitos. 

 Dr. Trelease of the Missouri Botanical Garden, to 

 whom we are indebted for information on this sub- 

 ject, suggests that the plants growing so thi'ckly on 

 the surface may make it difficult for the female mos- 

 quito to deposit her eggs, or that even if eggs are de- 

 posited, the small water animals including fish may, 

 under cover of the plant, dispose of the larvae. At 

 any rate, recent reports from the New Jersey experi- 

 ment station and from the United States Department 

 of Agriculture, recommend this plant as a mosquito 

 killer. Azolla is not very abundant in the Northern 



83 



