Fig. 145.—Section through marginal lobe of carpel, showing nucleus and tegument (Delphinium).
Fig. 146.—1. Placenta of Dianthus, bearing ovules and carpels. 2. One of the ovaries separated.
Fig. 147.—Ovules of Dianthus passing into carpels.
One of the most singular instances of ovular malformation in record is that cited by the Rev. M. J. Berkeley, in the 'Gardener's Chronicle,' September 28th, 1850, p. 612. The plant was a carnation, and its placenta bore, not only ovules, but also carpels (fig. 146), the latter originating in a perverted development of the former, so that many intermediate stages could be traced between the ordinary ovule and the ovary (fig. 147, 1, a, 2, b). Some of these carpels, thus derived from the ovules, themselves bore secondary ovules on a marginal placenta, as shown in the sections at c, d, e. Could such a change occur in the animal kingdom, there would be the unfertilised ovum converted into an ovary, and this again bearing Graafian vesicles! In Mr. Berkeley's carnation the change was not so great, seeing that the nucleus of the ovule was not developed, and sufficient evidence has been above given as to the foliar nature of the primine, while for a leaf to be folded up so as to form a carpel is an ordinary occurrence.
It is worthy of remark that in these foliaceous ovules there is never more than one coat, the secondine and other integuments do not make their appearance in these cases, and that very generally the change in question accompanies a similar foliaceous condition in the carpel, the margins of which are more or less disunited.
Prof. A. Braun remarks that up to this date no such change has been observed in the ovules of Monocotyledons.