Vallisneria Spiralis 



C. J. HEEDE 



I 



The subject of this article, Vallisneria 

 spiralis, the Tape or Eel-grass, is well 

 known to most aquarists. It ranks a close 

 second to the species of Sagittaria in 

 popularity, though it is not inferior as an 

 oxygenator, and is particularly useful in 

 self-sustaining aquaria. The generic 

 name, Vallisneria, was given by Carolus 

 Linneaus, the father of botany, in his 

 Species Plantarum, 1753, and was in 

 honor of Antonio Vallisneri, an Italian 

 naturalist who wrote on plants and in- 

 sects during the eighteenth century. The 

 specific name, spiralis, refers to the habit 

 of the stalk bearing the female flower. 



The species is dioecious, which means 

 that the sexes are distinct, an individual 

 bearing either male or female flowers, but 

 not both. The female or pistillate flower 

 has its origin in the rootstock, and is 

 born to the surface on a long, slender, 

 spiral stalk. Here it meets the male 

 flower, which had become detached from 

 its short stalk at the base of the staminate 

 plant, and pollination is effected. The 

 stalk of the pistillate flower recoils and 

 the seeds ripen below the surface. This 

 method of sexual reproduction is rather 

 uncertain, and is supplemented by multi- 

 plication by stolons or runners from the 

 rootstock, from the terminal of which 

 develops a new plant asexually. Several 

 plants may often be found attached in 

 this manner. The leaves are ribbon-like, 

 even in width throughout their length, the 

 tip abruptly rounded, and brilliant green. 

 The leaf-cells have long been a favorite 

 object, with microscopists to demonstrate 

 the movement of the protoplasmic con- 

 tents, and the tendency of the chloro- 



plasts (the grains of green coloring mat- 

 ter) to arrange themselves toward the 

 strongest light. 



In the United States Vallisneria is 

 widely distributed in ponds and slow 

 streams from the Mississippi Valley 

 eastward. Our native plants, though 

 presenting no botanical distinctions, dif- 



Typical Vallisneria spiralis (female plant) and the 

 Form With Tortuous Leaves 



fer in aspect and habits from the more 

 desirable European form. They are 

 broad-leaved, coarser, and do not thrive 

 throughout the year and multiply in the 

 aquarium. The European, or, as it is 

 sometimes called, the Italian Vallisneria, 

 has been known so long to American 

 aquarists that the native plant is seldom 

 used. As far back as 1902, Eugene 

 Smith, in his book, The Home Aqua- 

 rium, remarks that it is to be preferred 

 to the native form, and adds that it seems 

 to be represented here by male plants 

 only. 



A foreign publication has reported a 

 form with tortuous leaves that is said 

 to thrive in aquaria and maintain its char- 

 acteristics. The statement is made that 



