30 

 seems to come from difrerence in environments. But unvaried, forms 

 must have "been caused onoe by definite conditions. Porms which 

 are variable do become fixed in time and when plasticity is once 

 lost, it is lost forever. 



Reading— Coulter— Dhap. IV. — Shoots, p. 53-88. 

 Field Work July 18^ 1900 . 

 To study development of leaf teeth, use viburnum. Red Oak, Chestnut, 

 Circaea, Sycamore. 



Examples jqX climbing plant s . 

 Polygamum scandens. Bindweed. 

 Atnpelopsis quinquefolia. Woodbine. 

 Cuscuta, Dodder. Smilax. 

 Apios, tuberosa. Ho g .p eanut . 

 Rlaus toncoden. Poison ivy. 

 Amphicarpaea monoica. Hog-peanut. 



Climb by tendrils, stems, petioles, suckers, adventitious roots, 

 holdfasts. 



Lee Cut-grass, a half t climber, backward hooks on 



the leaves. Autumn coloration may be defined as the color of a 

 dying leaf. In such eases the color is usiially stronger in the 

 upper side of the leaf, seemingly associated with light. 



Disease will also cHuse coloration in plants, as rust in the 



dandelion. 



Field Work Julv 19. 1900. 



Roots and other absorbing organs . 

 Roots are generally fibrous. 



