Teachers' Leaflet. 555 



willow saplings smeared over with clay. In Europe willow raising and 

 willow weaving is now a regular industry; baskets, hampers, carriage 

 bodies and furniture are made for all the world. To get these twigs 

 the willow trees are " pollarded,'" which means they are cut back every 

 year between the falling of the leaves and the flow of the sap in spring. 

 In America large nurseries often grow willow to be cut back to the 

 ground every season for the making of withes for binding the bundles 

 of young trees: The making of willow ware in this country is a neglected 

 industry, the only center of much importance being at Syracuse, N. Y. 

 From willow is made charcoal of the finest grain, which ignites most 

 readily and is, therefore, used in the manufacture of gun powder. Sali- 

 cylic acid used widely in medicine is made from the willow bark, which 

 produces also tannin and some unfading dyes. 



Because the willow so readily hybridizes it is a very difficult group 

 to study with a view of determining species. 



References. — "The Tree Book," Rogers, page 115; "Our Native 

 Trees," Keeler, page 393 ; '' Getting Acquainted with the Trees," McFar- 

 land, page 97; " Familiar Trees and Their Leaves," Mathews, page iii ; 

 "With the Trees,"— Going,— 36 ; "Practical Forestry," Gifford (Bas- 

 ketry, 16; Soil Binding, 58; Pollarding, 183). 



LESSON CXXIV. 



THE PINE CONE WILLOW-GALL. 



Purpose. — To teach the pupils that the cone-like object found on 

 several species of willow is not the fruit of the willow but is made 

 by an insect. 



There appears on the end of the twigs of the Heart-shaped Willow 

 and certain other species, which grow about our streams, a cone-like 

 object. This is naturally considered a fruit by the ignorant. As we 

 have seen, the willow fruit consists of very small seeds, which sail away 

 on tiny balloons and the trees which have cones for fruits are the ever- 

 greens. This willow cone is made by a small gnat, which lays its eggs 

 at the tip of the twig ; as soon as the little grub hatches it begins to 

 gnaw the twig, and this irritation for some reason stops the growth. 

 The leaves instead of developing along the stem are simply dwarfed 

 and overlap each other. Just in the center of the cone and at the tip of 

 the twig the little larva lives its whole life surrounded by food and pro- 

 tected from enemies ; it remains safe in this cone all winter and in the 

 spring changes to a pupa, and after a time comes forth a very delicate, 

 little fly. The larva of this cone-gall is very hospitable ; it has its own 

 little apartment at the center, but it does not object to the spaces between 



