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 anything 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. 
