80 PRACTICAL COURSE IN BOTANY 



22. Is it a wise practice to mulch a tree by raking up dead leaves and 

 piling them around the base of the trunk, as is often done ? Why, or why 

 not? (66,89.) 



Field Work 



(1 ) Examine the underground parts of hardy winter herbs in your neigh- 

 borhood, also of any weeds or grasses that are particularly troublesome, 

 and see if there is an3'thing about the structure of these parts to account 

 for their persistence. Note the difference between roots of the same species 

 in low, moist places and in dry ones ; between those of the same kind of 

 plants in different soils; in sheltered and in exposed situations. Study 

 the direction and position of the roots of trees and shrubs with reference 

 to any stream or body of water in the neighborhood. (The elm, fig, 

 mulberry, and willow are good subjects for such observations.) Notice 

 also whether there is any relation between the underground parts and the 

 leaf systems of plants in reference to drainage and transpiration. 



(2) Observe the effect of root pull upon low herbs. Look along washes 

 and gullies for roots doing the office of stems, and note any changes of 

 structure consequent thereon. Study the relative length and strength 

 of the root systems of different plants, with reference to their value as 

 soil binders, or their hurtfulness in damaging the walls of cellars, wells, 

 sewers, etc. Dig your trowel a few inches into the soil of any grove 

 or copse you happen to visit, note the inextricable tangle of roots, and 

 consider the fierce competition for living room in the vegetable world that 

 it implies. 



(3) Tests might be made of the different soils in the neighborhood of 

 the schoolhouse by planting seeds of various kinds and noting the rate of 

 germination; first, without fertilizers, then by adding the different ele- 

 ments in succession to see what is lacking. The field for study suggested 

 by this subject is almost inexhaustible. 



