84 THE PLANT WORLD. 



their characteristics will be alluded to hereafter only in exceptional 

 cases. Mr. William C. Barbour, of Sayre, Pa., has kindly offered to 

 supply material of this species to any one who will enclose stamp for 

 return postage. 



Yale University. 



CULTIVATION OF ALQyt IN AQUARIA. 



SOME points relative to the cultivation of Algae in aquaria may be 

 helpful to amateur workers in this line. It is the usual practice to 

 collect Algae like Vaucheria, Spirogyra, etc., and put them in a 

 large glass vessel from one-half to two-thirds filled with water, 

 in the hope, that they will grow and fruit and thus furnish a supply of 

 material for future use. Very often, however, the plants soon turn yel- 

 low, decay and rise to the surface where they form a foul-smelling scum. 

 Usually the next step is to empty the aquarium. This should not be 

 done, however, as after a time the material settles to the bottom, new 

 growth starts, and if any spores of the desired Algae are present they 

 will grow along with the others and no further trouble will be experi- 

 enced. But it is better not to risk the loss of material by allowing it to 

 go through the fermentative process. In order to avoid fermentation 

 the water must be kept thoroughly supplied with oxygen. This can 

 sometimes be done by placing the Algae in a broad vessel with shallow 

 water, and aerating by dipping up some of the water and pouring it 

 back, allowing it to strike the hand held just above the surface of the 

 water in the vessel, so as to break the force of the descending stream, 

 and in this way prevent the disturbance of the colonies of Algae and 

 the stirring up of sediment. 



A better way, however, is to grow in the water some good aerating 

 plants like Myriophyllum, Cabomba, Ranunculus, Water Mosses, etc. 

 — in fact any submerged aquatic plants which give off bubbles of air 

 (largely oxygen) when exposed to light. Algae introduced in small 

 quantities into aquaria thus supplied with oxygenating plants will 

 thrive for long periods quite as well, if not better, than in their orig- 

 inal habitat. It is also well to introduce, if possible, some little fresh- 

 water Crustaceans; Cypris or Cypridopsis are especially good. They 

 are the most harmless of scavengers, living mainly on decaying veg- 

 etable tissue, or parenchyma. They are particularly fond of the 

 mesophyll of leaves, which they remove, leaving beautiful leaf skel- 

 etons. — Albert F. Woods in Journal of Applied Microscopy for Novem- 

 ber, iSg8. 



