478 MORPHOLOGY. 



thoroughly recognised that little need be said on that 

 score, save to repeat that the homology of the floral 

 organs is usually not so much with the entire leaf as 

 with its sheath. 



The most singular instances of morphological identity 

 are those relating to the sexual organs. We have seen 

 the gi'adual transition of stamens to pistils, and of pistils 

 to stamens, the development of ovules on the edges of 

 the anther, the co-existence of pollen with ovules on an 

 antheroid body, and, stranger still, the actual develop- 

 ment of pollen within the tissues of the ovule itself! 

 From such facts, in addition to what we know of 

 the relative position, internal structure, and mode of 

 development of the organs, it is impossible to avoid 

 coming to the conclusion that, however distinctly these 

 parts may, under ordinary circumstances, be set apart 

 for the performance of distinct functions, morpho- 

 logically they are homologous. 



These ideas may be carried yet farther the same 

 sort of evidence, which is adduced in support of the 

 morphological identity of leaves with the parts of the 

 flower, may be advanced in confirmation of the opinion, 

 that, morphologically, there is no distinction between 

 axis and leaf. The leaf, according to this view, is a 

 specialised portion of the axis set apart to do certain 

 work, just as the petals, stamens, &c., are leaves told 

 off for distinct uses. It is unnecessary to refer to the 

 intermediate productions linking the leaf-form to that 

 of the axis, all that is requisite here is to point out 

 the facts that teratology lends in support of these views. 

 These may be summed up by the statement that almost 

 all those attributes which morphologists recognise as 

 peculiar to one or the other organ respectively, may 

 be and are manifested by both. "We have the stem 

 acquiring the characters of the leaf, and the leaf those of 

 the stem. Thus we have seen leaves, leaf-buds, branches, 

 and flower-buds spnnging from leaves or leaf-organs ;^ 

 see pp. 174, 177, 445, &c. The structure that we 



' An additional illustration of this may bo cited, which has been 



