THE AMERICAN BOTANIST 



111 



appear. The first pines were jack pines. These were sooner 

 or later crowded out by the Norway or red pine, and these in 

 turn gave way to the white pines. At this stage of the pro- 

 ceedings man happened along and cut down the pines. Had 

 he not interfered, the white pines would not have been able to 

 hold the ground for long. The white pine forest is not self- 

 perpetuating. The seedlings do not grow well in the dense 

 shade of their elders, though this shade is acceptable to young 

 maples, beeches and other broad-leaved trees. In consequence 

 the ground under the pines was covered with broad-leaved 

 seedlings and when the pines died they were replaced by broad- 

 leaved trees. These latter form the climax formation of vege- 

 tation for the region. In other regions the climax formation 

 may consist of grasses but until the climax is reached, one plant 

 group after another must give way to the advancing plants." 



Flowers as Specific Characters. — In classifying plants 

 the important characters are practically always taken from the 

 flowers and fruits. Of course there are many distinguishing 

 characters taken from the leaves, stems, roots, and other plant 

 parts, but the principal ones are furnished by the flowers. The 

 reason for this is that flowers are less likely to vary than other 

 parts of the plant. All the activities of plants and animals may 

 be grouped either as grow^th or reproductive processes. Growth 

 may take on a variety of forms depending considerably upon 

 the location and opportunities of the individual, but reproduc- 

 tion is not so easily modified and the reproductive organs are 

 therefore less likely to vary. As a consequence, when any no- 

 ticeable difference occurs in these parts, it is likely to indicate 

 considerable differences in the whole organism^ When man 

 first began to classify plants, he seems to have been inclined to 

 classify them by their vegetative parts. A favorite division, 

 which has not yet lost its value for some purposes, was into 

 herbs, shrubs and trees. Such a division, however, often sep- 

 arates closely related plants. It was probably quite by accident 



