504 NATURE-STUDY 



on paper. Perhaps simple experiments in growing them 

 may be tried. Do nothing with the prothallial stages nor the 

 alternation of generations. Examine the pond scum with 

 a low-power compound microscope. (193, 152, 156, 159 

 172, 179, 475c.) 



Plant diseases: Wheat rust, apple rust, sunflower leaf 

 rust, lilac and woodbine leaf blight, potato rot, corn smut 

 black knot, tree shelf fungi * and toadstools.* Consider 

 chiefly from the economic standpoint. Do very little with 

 structural details not visible with the naked eye or a simple 

 magnifying glass. Spores may be shown in mass on paper. 

 Consider the extent of damage done to crops and trees. 

 Read up about remedies, especially sprays. (190, 153, 167, 

 180, 220, 231, 230, 221, 241, 226, etc., 246 " Fungicides.") 



Winter 

 Plants. 



Forestry: Uses of forests: Fuel, lumber, wind-breaks, 

 game, nuts, and fruit, maple sugar, paper pulp, Christmas 

 trees, telegraph and telephone poles, fence posts, and ties. 

 Importance in conserving the soil moisture, retaining fertility, 

 protecting the soil, controlling off-flow and preventing floods, 

 and acting as reservoirs for rivers and irrigation purposes. 

 Health resorts, scenery. Discuss the enemies of forests : Far- 

 mer, lumberman, etc., forest fires, browsing cattle and sheep, 

 storms, drought, injurious insects, parasitic fungi. Discuss 

 the life-cycle of a tree — youth, maturity (how old), old age 

 and decline. The use of forests as a crop, conservative 

 cutting, protection, replanting or allowing natural reforest- 

 ation. How forests naturally reproduce themselves — cop- 

 pice method, self-sowing. Show pictures or visit planted 



