1905] Leavitt, — Translocation of Characters in Plants 19 
these organs accord with leaves in mode of origin, position and 
arrangement; or at most that they are of one name, ideal plan, or 
pattern. There is no implication of common historic origin. Simi- 
larly “reversion” means in Dr. Gray’s language no more than 
descent in the scale of forms subsumed under the ideal conception 
or type, Leaf. “The substance of the doctrine [Goethe’s doctrine 
of metamorphosis] is unity of type” (p. 169). Dr. Gray’s “rever- 
sion ” is the “retrograde metamorphosis ” of Goethe. 
In the section on monstrous floral structures Dr. Gray uses the 
word reversion in this abstract sense, with no connotation as to the 
phylogenetic derivation of the organs in question. This attitude is 
betrayed by the expression (p. 172) “the reversion of the pistils to 
stamens.” The author of the Structural Botany could not have held 
that pistils have been derived historically from stamens. His pre- 
sentation of the teratological facts, however, is entirely permissible 
if the word reversion is understood in the older sense. Throughout 
the section on the morphology of the flower, Dr. Gray’s position is 
that of Wolff, Goethe and De Candolle, whose researches, with the 
later investigations of phyllotaxy, Dr. Gray holds to have completed 
the evidence of the morphological unity of foliaceous and floral 
organs (p. 168). While at the present time we may safely enlarge 
our definition of homologous; and while the conclusion that floral 
appendages and vegetative leaves are homologous rests on a basis 
far broader than that of phyllotaxy, transition and “retrograde meta- 
-morphosis,” yet Dr. Gray's treatment of monstrous forms is unim- 
peachable. He does not venture far into a field in which he doubtless 
descried numerous pitfalls. 
However, the employment of the word reversion by the older 
writers has doubtless contributed to the confidence with which some 
subsequent authors have given utterance to unwarranted interpreta- 
tions. Observers of to-day are imbued with the ideas of the descent 
theory; they have taken up the term “reversion” and have applied 
it in a new way in consonance with modern evolutionary ideas. 
Their reversions are therefore, as they suppose, genuine reappear- 
ances of ancestral traits, or restoration of organs to conditions from 
which they have departed in the course of evolution. 
(To be continued.) 
