Leaf Variation — Its E.xteiit a>id Significance. 49 



LEAF -VARIATION — ITS EXTENT AND 

 SIGNIFICANCE. 



Mrs. W. a. Kellerman. 



Read at IVIeeting of Ohio Acadetiiy of Science, Dec. 29, 1892. 



The voice of Nature is, perhaps, nowhere more potently 

 heard than in her nnpruned gardens, her fertile meadows and 

 woodland hills. She speaks, however, not onl}- through the 

 general beauty of the landscape, but also through the leaves 

 of every plant that grows, affirming through them the univer- 

 sality of the law of evolution, by emphasizing its underlying 

 principle, "from the simple to the complex." 



The herbs of the garden, the plants on the lawn, the shrubs 

 and trees on every side, all indicate, by the variation of their 

 leaves from typical forms, that they are not cast in a mold 

 from which there is no deviation. Take, for example, the 

 leaves of the potato, tomato, the dahlia, the elder, the black- 

 berry, the walnut, the Liriodendron, etc., etc. The more care- 

 fully the}' are studied, and the more closely they are observed, 

 the greater the degree of variation found existing between 

 the leaves of any one plant. The leaves of the Liriodendron 

 especially are considered as subject to slight, if indeed any, 

 variation. Careful study of them, however, has brought to 

 light some exceedingly interesting forms, many of which vary 

 so much from the present typical leaves, that they would 

 scarcely be considered as belonging to the same species. Had 

 they been found as fossils, no doubt paleontologists would 

 have coined specific names for each one of them. 



In the Spring, when the sleeping forests have burst forth 

 into new life, and the beautiful leaves again clothe the barren 

 branches; when the little seedling plants have pushed their 

 way through the mellow soil, there is abundant opportunity 

 for studying leaf-variation. 



