244 M.DuchsLvtre on the Orffanoffeny of the Malvacex. 



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 lie 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 into a mi- 

 nute filament which becomes more and more elongated. Each 

 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 distinct whorl, but form a part of that of the corolla. The de- 

 velopment of the flower of the Malvacea 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 Mijrtacece, Hypericacea, &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 



