286 ECOLOG Y. 



455. Topics for ecological study. — Some of the topics for 

 ecological study and observation which can be taken up by 

 beginning classes are suggested here. The order in which they 

 may be taken up for study may be dependent to a large extent 

 on the time of the year at which the study is made, and also 

 upon the nearness of the school to the supply of material. But 

 in any place, even in large cities, there are abundant supplies 

 of material for several topics, and by foresight preparation can 

 be made in advance for others. 



Studies in Perennial Shoots, the annual growth as determined 

 by the ring scars, or position of branches. 

 Trees. 



Trees with the main shoot continued through as a central 



trunk, as in the pines, spruces, larches, etc. 

 Trees with a deliquescent trunk, where the main shoot is 

 lost by continual branching, as in the elm, etc. 

 External character of the bark of different trees, and the 

 variation in character of the bark of certain species at 

 different ages. 

 Branching of shoots, different types of, in trees, shrubs. 

 Underground shoots, as in certain ferns like the brake, sensi- 

 tive fern, where long horizontal shoots are formed, or in 

 the mandrake, the toothwort, etc. 

 Creeping shoots or runners, or trailing shoots as in the poly- 

 pody, the strawberry plant, the clematis, grape vine, club 

 mosses, and others. 

 Perennial underground shoots which bear aerial annual 

 shoots, as in trillium, the mandrake, jack-in-the-pulpit, 

 blood-root, etc. Many of these shoots also contain stored 

 nutriment for the growth of the annual shoot. 

 Studies of Leaf Arrangement can be made from the bare 



shoots by observing the positions of the leaf scars. 

 Studies of Buds and Bud Formation, protection of buds dur- 

 ing the winter, opening of the buds. 



