AQUATIC PLANTS OF FRESHWATER 



Others, are generally to be had and may be planted with the lower ends 

 embedded in the sand or pebbles or loosely floating on the surface of the 

 water. They require a strong light and grow very rapidly. Goldfishes 

 destroy them but with Paradise fishes or for snail culture, they form hand- 

 some aquatic gardens. 



A peculiar characteristic of the Bladderworts is that they are aquatic 

 insectivorous plants. The bladders are provided with a valvelike trap on 

 their lower sides and when filled with water also probably contain secre- 

 tions which attract infusoria and small crustaceans, who upon entering are 

 entrapped and absorbed by the plant. Of some species it is reported 

 that they will capture the tiny fry of fishes, though in these latitudes there 

 is no species with bladders sufficiently large to serve this purpose. 



HOTTONIA 



This pretty marsh herb is commonly known as Featherfoil, Water- 

 feather, Water or Marsh-violet and Water-yarrow. Two species are 

 native to North America. 



Hottonia inflata (Ell.) or Water-feather having an entirely submerged 

 spongy close cluster of thick and soft stems with pinnate crowded leaves 

 in verticils and clustered at the ends and joints of the stems. An interest- 

 ing pond plant but does not usually survive in the aquarium. 



H. palustris (Ell.) the second species is more rarely met with, but in 

 Europe is considerably cultivated as an aquarium plant. 



FRESHWATER ALG^ 



The Algae constitute one of the grand divisions of the Cryptogams 

 or flowerless plants, embracing the sea weeds and lower water plants, 

 the Fucas, Ulva and Confervse. The most of the Fuca and Ulva are 

 marine forms; but in counterdistinction to Algae in general, the Confervae 

 are an extensive section of the order of Algae, consisting of slender, often 

 scum-like vegetation, the best known being the so-called "Frog-spittle." 

 The simpler forms of Algas, the Nostoceae, consist only of a cell wall con- 

 taining a colored protoplasmic substance; but in the higher forms the cells 

 are combined into a tissue, and the forms which they assume are more varied 

 than in any other class of plants. Some appear as strings or linear masses, 

 globules, lamina, etc. In others, the Fucaceae, a distinct stem, branches, 

 leaflike structures and rhizoids or rootlike structures are formed, but these 

 have none of the characteristics of true plants and consist entirely of 

 cellular tissue. 



Each season of the year, every climate, every moist spot, has its species 

 of Algae. Some may be found in healthy condition frozen into an icicle 



zo6 



