Aquarium Plants 79 



placed on a bifurcated stem. After the 

 flowering 1 they sink below the surface to 

 ripen their hard seeds. The plants need 

 plenty of light, a loamy soil and the tem- 

 perature of a living room. They propagate 

 from both seeds and roots. 



Water-nut (Trapa natans), formerly of 

 frequent occurrence in the ponds and 

 swamps of Germany, but now quite rare. 

 The black seed, or nut, has four strong thorns 

 and a chestnut-like kernel. The seed will 

 germinate if placed in a glass of water in 

 a cool, but not cold room. A thin stem, with 

 finely divided leaves placed in pairs, will 

 appear first and wind its way toward the 

 surface of the water, where it will form a 

 rosette of floating leaves, which are strongly 

 dentated, of leathery texture and reddish 

 color. In June the small white flowers ap- 

 pear at the base of the leaves, where they 

 form seeds. The plant is an annual, and 

 is one of the most interesting of our aquatics, 

 well deserving a trial in the aquarium. 



