244 M.Duchartre on the Organogeny of the Malvaces. 
concentric formations so as to produce a system of stages ar- 
ranged one above the other; and although they enlarge at the 
same time, they do not do so in the same proportion. The or- 
gans which enlarge do not then find sufficient room to he side by 
side in regular and concentric circles ; they become rather con- 
fusedly mixed, and the original symmetry becomes less and less 
apparent. When they have arrived at a certain degree of deve- 
lopment, each of the tubercles shrinks up at the base mto a mi- 
nute filament which becomes more and more elongated. Hach 
also becomes marked by a median furrow, and buried within 
two cells which subsequently fuse into a single one. In short, 
these are so many reniform, unilocular anthers, which tend more 
and more to assume their definite form. 
In several species M. Duchartre has observed an ulterior change, 
from which a new increase in the number of stamens results. 
Several of them are curved into a horse-shoe form, and termi- 
nate by becoming divided into two by a constriction of the sum- 
mit of their curve,—a constriction which ends by forming a com- 
plete solution of continuity ; this, extending from above down- 
wards, also divides the filament which was at first simple into 
two corresponding to the anthers thus formed. This is a true 
duplication. 
This term would apply with less accuracy to the anterior for- 
mations, from which the multiplication of the stamens has re- 
sulted; for we may say, that at each of these changes they have 
doubled rather than multipled. Be this as it may, we have 
clearly five groups of organs alternating with the five leaflets of 
the calyx, each comprising a petal and several stamens, supported 
upon a base which is common and simultaneously developed. This 
is the whorl which is within and alternate to the calyx, and which 
is ordinarily called the corolla, with this difference, that here each 
petal is replaced by a group or bundle of organs. 
One of us has long since professed the doctrine, that in those 
flowers which have stamens double in number to the petals, 
whenever the stamens of the external row are opposed to the 
petals (and this is most frequently the case) they do not constitute 
a distinet whorl, but form a part of that of the corolla. The de- 
velopment of the flower of the Malvacee supports this opinion, 
exhibiting to us each of the petals, opposed, not to a stamen, but 
to an entire bundle. We may add, that such appears to be the 
most common symmetry in polyadelphous polypetalous flowers, 
as is seen in so many Myrtaceae, Hypericacee, &c., where the 
bundles, which are perfectly distinct, are opposite to the petals. 
But what has become of the normal whorl of the stamens,—that 
which should alternate with the petals ? M. Duchartre discovers 
this in the five terminal lobes of the staminal tube, situated upon 
