208 
summer conditions, and the features pointed out by which they 
may most easily be recognized. ‘Two credits. This course is the 
same as A5 and A9, and is therefore free to members of the 
Garden. Fee to non-members, $10. Saturdays, 2:30 p.amn., Sep- 
tember 28 to December 14; and April 4 to June 20. (Omitting 
October 12, November 30, April 11, and May 30.) 
Dr. Graves and Miss Vilkomerson. 
*B15-16. Economic Plants.—Thirty sessions. The most 
important economic plants of the world are considered—their 
history, culture, formation of their useful products, and the ex- 
traction and preparation of the latter by man. Herbarium speci- 
mens and other material, as well as living plants in the conserva- 
tories and plantations of the Garden will be used for demonstra- 
tions. Because of its practical applications, this course will be 
of special value to teachers. Two credits. Fee, $10. Mondays, 
4 p.m., beginning October 7. Dr. Cheney. 
B17. Genetics.—Thirty class meetings and fifteen 2-hour 
laboratory periods. An introductory course in heredity and 
variation, including discussion of Mendelian principles, the phys- 
ical basis of heredity, sex linkage, factor linkage, factor interaction, 
and quantitative inheritance. Laboratory work on plant material 
and Drosophila, Prerequisite: an elementary course in botany. 
Three credits. Fee, $10. Mondays, 4 p.m., beginning September 
16; and Thursdays, 4-6 p.m. (laboratory), beginning in December 
or January. Miss Rusk. 
C. Children’s Courses 
Saturday morning classes for bovs and girls are open to children 
from eight to nineteen years old. Children are grouped in these 
classes according to age and experience. 
Miss Shaw and Assistants. 
I. The Fall Course takes up nature study on the grounds; 
plant propagation in the greenhouses, using stem and leaf cuttings; 
bulbs and corms; making of terrariums and dish gardens. En- 
rollment limited to 175 children. Fee, ten cents. Saturday morn- 
ings, 9-11:15, October 19 to December 21. 
II. Winter Course.—Children who have shown unusual abil- 
ity are chosen from the fall group for winter work. Introduction 
