HAVE PLAXTS A PEDIGREE? 141 



Theoretically the plant is a leaf. The axis or stem is a fused series 

 of midribs. The floral organs are leaves variously modified. Nay 

 we may look even beyond the leaf to the comj^onents of the leaf, for 

 thought cannot rest till it finds the ultimate unit. This is a cell, and 

 the lowest plant is sbnply a cell. Cells adherent to cells form a frond. 

 A frond, by a little modification, passes into a leaf, and a leaf into a 

 part of the flower. A sepal is a leaf changed but little ; a petal is a 

 leaf changed in color and texture ; a stamen is a leaf changed in color, 

 texture, and form, the blade being eliminated except at the tip where it 

 forms the anther, and the midrib remaining as a supporting filament ; 

 the pistil is a leaf with the lower part of the blade rolled up, and the 

 edges united to form a carpel, and the midrib prolonged into a style, 

 bearing atop a little shred of altered leaf-blade called a stigma. And 

 here — at the very tips of these inner leaves where the nutriment 

 is least and the vital force weakest — the investing membrane disap- 

 pears ; Nature slips back toward her simplest types, and shows us the 

 naked primordial cells as pollen-grains ! In the thistle one may see 

 that the stem is continuous with the midrib of the leaf. Every ob- 

 server knows that in the pond-lily (Fig. 8) we see the intermediate 

 stages between a simple leaf and a pistil. And every one whose gar- 

 den furnishes a syringa or double-flowering cherry, has only to look at 

 the flowers to see pistils and stamens reverting to leaves. 



Section of an Apple. 

 a a, carpels ; 6, remnant of pistils ; c c, remnants of corolla ; d d, remnants of calyx ; 



/, fibrous line. 



Fortunately for science, there grows in Kittanning, Pennsylvania, an 

 apple-tree, which, in its flower and fruit, exemplifies the theory of the 

 plant. Theoretically, a fruit is a branch with its leaves transformed. 



