98 THE AMERICAN BOTANIST, 



The Christmas Tree Crop. — American Gardening' 

 estimates that five million Christmas trees were cut in the 

 State of Maine this season. 



The Flowering of the Lakes. — In many of our 

 northern lakes, about mid-summer, each year, the water 

 becomes filled with small golden globules about the size of 

 a pin head. This phenomenon is called by the guides the 

 "working" or "flow^ering" of the lakes and in England 

 is known as the "breaking of the meres." The appearance 

 is due to a blue-green alga, Rivularia echinulata which 

 rises toward the surface in such multitudes as to become 

 very noticable. An account of the flowering of the lakes 

 in the Adirondack^ from wdiich the above note is tidvcn^ 

 was published in Torreya for October, 



Latex. — Many plants among which the rubber trees 

 are prominent, have a milky juice technically called latex, 

 whose use to the plant is still a matter for speculation, 

 The solution of the problem is also a matter of some com- 

 mercial importance, for not all rubber trees produce this. 

 latex, and of those that do, there is, of course, consider- 

 able variation in the amount yielded bj" different individ- 

 uals. Rubber is obtained from this latex and if the cause 

 of its production w^ere known it would probabl}'' be pos- 

 sible to stimulate the plants to greater productiveness. 

 The problems presented by the latex are discussed at some 

 length in a recent Government publication on the culture 

 of the Central American rubber tree by O. F. Cook. Ac- 

 cording to Prof, Cook, the rubber in the latex is of no use 

 to the rubber tree, and in different parts of the tree, the 

 rubber is often replaced by a substance that hardens upon 

 exposure to the air into a non-elastic resin. Some botan- 

 ists have believed that the kitex tubes are reservoirs for 

 the storage of elaborated food materials and others have 

 insisted that the latex is simply a waste product. It has 

 also been suggested that latex protects the tree from in- 

 sects. A microscopical examination has shown that each 

 tiny globule of rubber in the "milk" is surrounded by a 

 thin coating of protoplasm which shows that the rubber 



