208 PRACTICAL BOTANY. 



2. Dig up some very young Pines those of the 

 present season's production, for instance. Is there a 

 central taproot, or is the main root lost by division into 

 branches ? Compare with the root of a tree three or four 

 years old. Describe the mode of branching. Notice and 

 describe the rootlets. Draw enough to give a good idea 

 of the gross morphology of the root. 



3. Study the male flowers. These are to be obtained 

 only in the spring. They mature in May or June. Alco- 

 holic material may be used for the observations. The 

 male flowers may be obtained from various species, but 

 are most surely to be found on the Scotch Pine, the 

 Austrian Pine, and the Red or Norway Pine, descriptions 

 of which are given in various botanies. The male flowers 

 are borne as small yellow cones at the base of the shoot 

 of the new season's growth. Are these cones sessile, or 

 are they borne on stalks? Draw "an entire cone. Is 

 there any definite arrangement of the modified leaves 

 which compose the cone ? Are these leaves, the sta- 

 mens, sessile or borne on stalks? Remove some of the 

 stamens and examine them for the pollen, sacs. On which 

 surface of the stamens, and where on the surface, are the 

 pollen sacs borne ? What is the shape of the pollen sacs ? 

 Find mature specimens. How do the pollen sacs open? 

 Draw, showing an entire stamen. Examine under high 

 power some of the pollen grains. Draw. Apply re- 

 agents, if necessary, and determine whether there is a 

 nucleus and nucleolus. Is starch present ? Is oil present ? 

 If starch and oil are present, are they evenly distributed 

 in all parts of the grain? Make out two coats in the cell 

 wall. Prove that the outer is composed of lignified cel- 

 lulose and the inner of normal cellulose. When the 

 pollen grain develops in contact with the ovule, the inner 

 coat grows into the tube which penetrates the micropyle 

 of the ovule. 



