A MANUAL OF BOTANY 51 



bloomers ; have inconspicuous flowers. What agent for pol- 

 lination, therefore, do these trees and shrubs require ? What 

 advantage is the early date of blooming ? 



Ten important trees belonging to these orders are : 

 (l)Oaks; (2) Chestnut; (3) Beech; (4) Birch; (5) Cot- 

 tonwood; (6) Osier; (7) Aspen; (8) Filbert; (9) Horn- 

 beam; (10) She-oak. What economic value has each? 



3. The Trillium Species 



Species available ; habitat. For this study any species of 

 trillium is equally good, but for the reason that T. recurva- 

 tum, or the bloody butcher, is not picked for its blossoms, 

 good judgment dictates that it is the best one to study, 

 because one is not hastening the extermination of a beautiful 

 plant by so doing. It may be commonly found blooming in 

 all rich woodlands in the northern parts of the United States 

 about May 1. A few complete plants should be procured in 

 addition to the flowering stems. 



The plant. Examine the whole plant and observe the 

 thick rhizome from which the flower stalk grows. Where 

 do the roots grow and what are their peculiarities ? 

 Find an apical hud immediately at the base of the ascend- 

 ing stem. 



Study the erect aerial stem. Observe its varying color 

 from base to summit. How do you explain it ? How many 

 leaves does it bear? Examine the leaves for shape, size, 

 color, and venation. 



What is the position of the flower with reference to the 

 leaves ? Is the flower with a stalk {peduncle) or witliout 

 (sessile) ? 



Study a cross section of the stem (m). What is the ar. 

 rangement of the tissues? Is the stem mono- or dicotyle- 

 donous in structure? Draw the whole plant, also the stem 

 section (?;i). 



