THE AMERICAN BOTANIST 



105 



the bud scales of the peony excrete a sweet fluid of which the 

 ants are very fond. Several varieties of ants visit other plants 

 for nectar excreted by leaves and other parts as well as by flow- 

 ers, but they also visit the plants for the honey-dew excreted 

 by the plant lice, which may often be found feeding on the un- 

 derside of leaves and on other plant parts. When the plant lice 

 become crowded in a particular location the ants are not above 

 carrying them to fresh fields and so aid in spreading the pests. 

 It will be seen, therefore, that ants, while not harmful in them- 

 selves, may become so in spreading other pests. At the same 

 time it may be said that when a plant excretes nectar on its veg- 

 etative parts, the ants which feed on it often act as a fairly ef- 

 ficient body guard and drive off other insects. Some of the 

 tropical ant plants were once reputed to produce food for the 

 ants and to have thorns modified for use of ants as shelters in 

 return for the ants officiating as a defensive army, but that there 

 is any direct connection between the supplying of food and shel- 

 ter to the ants and their protection of the plant is now denied by 

 botanists. 



Age of Trees. — Inquiries as to the general age of trees 

 have shown that the pine tree attains TOO years as a maximum 

 length of life; 425 years is placed as the alloted span of the 

 silver fir; the larch lives as a rule about 275 years, the red beech 

 245, the aspen 210, the birch 200, the ash 170, the alder 145, 

 the elm 130. Of the holly it is said that there is a specimen 410 

 years old near AschafTenburg, Germany. A count of the annual 

 rings in a gigantic California redwood showed that it began 

 growth in 550 A. D. It was 300 feet high with a base cir- 

 cumference of 90 feet. — Journal of Horficiilfiire. [It may be 

 said in this connection that the alder mentioned above is not the 

 American shrub so common along streams in many places, but 

 the European alder which becomes a tree. The elm, also is not 

 our common species,- but the species found in Europe, U linns 

 campestris. Our elm often attains a much greater age. — Ed.j 



