Hunter, _Laboratory Problems in Civic Biology_. American
Book Company.
Gannet, _Commercial Geography_. American Book Company.
Sargent, _Plants and their Uses_. Henry Holt and Company.
Toothaker, _Commercial Raw Materials_. Ginn and Company.
U. S. Dept. of Agriculture, Farmers' Bulletin 86, _Thirty
Poisonous Plants of the United States_, V. K. Chestnut.
Bulletin 17. _Two Hundred Weeds, How to Know Them and How to
Kill Them_, L. H. Dewey.