An Historical Sketch. 6r 
a structure capable of further development, is proved by the following 
phenomena : — 
(1) Multiplication of integuments, the latter arising in acropetal suc- 
cession (he thinks that it is not strange that the abnormal integuments 
should arise in the opposite direction to that of the normal ones, seeing 
that the regions from which the annular protuberances arise are already 
formed). 
(2) Unilateral expansion of one or both integuments. 
(3) Proliferation of the ovule into an elongated shoot. 
(4) Production of a leafy bud in place of the nucellus within the 
normal integuments. On one leaf of this bud he found an ovule, which he 
regards as a case of ‘ one ovule arising out of another. 5 
Having introduced Al. Braun first, as the most important of the sup- 
porters of this theory, let us now take up the views of the remaining authors 
in the historical order of their publication. We find that in 1840 Aug. de 
St. Hilaire (6), in his noteworthy ‘ Legons de Botanique 5 (p. 543), in support 
of the axial-theory of the ovule remarks: ‘ We can only regard the ovule 
as a miniature branch composed of an axis and appendicular organs. The 
placenta, as we already know, is a continuation of, and represents the stem, 
whose branches are the ovules. 5 4 The primine and secundine are the appen- 
dicular organs of the young branch, and are comparable to the sheathing leaf- 
bases found in great numbers of Monocotyledons . . . ; it is therefore not sur- 
prising that the ovular axis, the least vigorous of all axial structures, should 
produce nothing but such sheaths. 5 On p. 490 he further says : ‘ We know 
that every part of a plant bearing ovules — or, rather, every placenta — springs 
from the axial system, and is nothing more than a prolongation of this 
latter ; so that in cases of axile or parietal placenta it is clear that the axis 
of the flower, after producing the carpellary leaves, has, in order to produce 
ovules, to divide by means of a partition, for supplying branches, double or 
equal in number to that of the carpels, but which, in the latter case, are 
susceptible of forming double placentas. 5 
This same view, as to the universally axial nature of the placenta, is put 
forward by the author in his earlier memoir on the Resedaceae. As afford- 
ing a slight variant on the axial-theory, the coupled names of Endlicher and 
Unger (8) may be introduced, who held the ovule to be of the nature of 
a disc (‘ Nebenaxe ’) produced on the axial placenta. 
Schleiden (14), who, in 1839, as also in his subsequent work the ‘ Grund- 
ziige der wissenschaftlichen Botanik, 5 published in 1843, promulgated, like 
St. Hilaire, the view that the placenta is always an axial structure, and that 
the ovules borne on it are of the nature of buds. Doubtless, this view of the 
matter, owing to the great weight of the epoch-making work containing it, 
would have had much influence both among the author's contemporaries 
and among many of those who came after him. 
