— 
Coco ow y volitemt NN IECUR pep 
— T 
ON THE SEXUAL ORGANS OF THE CYCADACEE, 67 
that of Rossmann. According to this observer (Bot. Zeitung, 1855, p 
666) from the examination of a monstrous 4quilegia, the border of the 
carpellary leaf divides into as many lobes as there are funicles. These 
are the equivalents of the lobes, and bear the ovules which originate in 
the parenchyma of the lobes, but the nucleus is a new and distinct 
(Neubildung) production, giving rise also to the formation of the coats, 
According to this view, the coats would neither be a product nor a pro- 
longation of the edges of thecarpel. Brongniart had previously based on 
a monstrous Delphinium the following theory :— An ovule is the equiva- 
lent of a lobe or tooth of a leaf. The funicle with the raphe, as far as 
the chalaza, are formed by the vein of the lobe. The nucleus is an in- 
dependent formation which makes its appearance on the upper surface 
of the lobe, but the coats are nothing more than the folded extremities 
of the lobe (** Lobe foliacé replié sur lui-méme en formant une sorte 
de capuchon,” Archives du Muséum d'Histoire Nat, iv. 1844). 
For anatropous ovules there is something seductive about this theory, 
but it leaves unexplained the existence of double coats, and does not 
determine the precise point from which the formation of the nucleus 
starts. The observations on which it rests as well as those of Wesmael 
(Bulletin de l'Académie de Bruxelles, xviii. p. 12) of the gam 
ment of ovules by leaflets or leafy lobes, are of great value as ar- 
guments against the theory of axile placentas, but they do not at pre- 
sent appear to be able to supply an adequate explanation of the 
formation of the ovules themselves.* 
The production of ovules on the edges or upper surface of carpellary 
leaves has been well compared to the formation of buds in the same 
‘positions on ordinary leaves,—a phenomenon which is far from being 
uncommon, either in cultivated or uncultivated plants, and which, con- 
sidering the low differentiation of the tissues in the vegetable organism, 
is not very remarkable. The unintermitted production of a succession 
of buds and axes, which remain united, or separate as distinct indi- 
viduals, is the essential character of all plants. Although as yet it has 
eluded direct observation, we can only picture to ourselves the forma- 
tion of a bud as originating in a cell differentiated from neighbouring 
cells. In this cell therefore the bud, that is the new individual, is 
* The observations " Marcha nd aerei iv. p. 189), = z dispensa" 
as, xxviii. p. 111), on ovules: partly tran: paires ed in well 
as those of Cramer, are only known to me in fion quotations, 
