44 MORPHOLOGICAL DEVELOPMENT. 



arrived at his conclusions independently. But that they 

 were original with him, and that he gave a more variously- 

 illustrated exposition of them than had been given by Wolff, 

 does not entitle him to anything beyond a secondary place, 

 among those who have established this important generaliza- 

 tion. 



Were it not that these pages may be read by some to 

 whom Biology, in all its divisions, is a new subject of study, it 

 would be needless to name the evidence on which this now- 

 familiar generalization rests. For the information of such 

 it will suffice to say, that the fundamental kinship existing 

 among all the foliar organs of a flowering plant, is shown by 

 the transitional forms which may be traced between them, 

 and by the occasional assumption of one another's forms. 

 " Floral leaves, or bracts, are frequently only to be distin- 

 guished from ordinary leaves by their position at the base of 

 the flower; at other times the bracts gradually assume more 

 and more of the appearance of the sepals." The sepals, or 

 divisions of the calyx, are not unlike undeveloped leaves: 

 sometimes assuming quite the structure of leaves. In other 

 cases, they acquire partially or wholly the colours of the 

 petals — as, indeed, the bracts and uppermost stem-leaves 

 occasionally do. Similarly, the petals show their alliances to 

 the foliar organs lower down on the axis, and to those higher 

 up on the axis. On the one hand, they may develop into 

 ordinary leaves that are green and veined; and, on the other 

 hand, as so commonly seen in double flowers, they may bear 

 anthers on their edges. All varieties of gradation into 

 neighbouring foliar organs may be witnessed in stamens. 

 Flattened and tinted in various degrees, they pass insensibly 

 into petals, and through them prove their homology with 

 leaves; into which, indeed, they are transformed in flowers 

 that become wholly foliaceous. The style, too, is occasionally 

 changed into petals or into green leaflets; and even the 

 ovules are now and then seen to take on leaf-like forms. 

 Thus we have clear evidence that in Phaenogams, all the 



