[368ON THE PLURALITY, &c.[1]
The following short paper on a subject which I intend to treat at greater length, contains a few facts of sufficient interest perhaps to admit of its being received as a communication to the present meeting.
In my observations on the structure of the female flower
- ↑ Read before the British Association at Edinburgh in August 1834, and published in the Annales des Sciences Naturelles for October 1843. The following abstract was given in the "Report of the Fourth Meeting of the British Association," 1835, pp. 590-7:—"The earliest observations of the author on this subject were made in the summer of 1826, soon after the publication of his remarks on the female flower of Cycadeæ and Coniferæ. He then found that in several Coniferæ, namely, Pinus Strobus, Abies excelsa, and the common Larch, the plurality of embryos in the impregnated ovulum was equally constant, and their arrangement in the albumen as regular as in Cycadeæ; and similar observations made during the present summer on several other species, especially Pinus sylvestris and P. Pinaster, render it highly probable that the same structure exists in the whole family. The first change which takes place in the impregnated ovulum of the Coniferæ examined, is the production or separation of a solid body within the original nucleus. In this inner body, or albumen, several subcylindrical corpuscula, of a somewhat different colour and consistence from the mass of the albumen, seated near its apex and arranged in a circular series, soon become visible. In each of these corpuscula, which are from three to six in number, a single thread or funiculus, consisting of several, generally of four, elongated cells or vessels, with or without transverse septa, originates. The funiculi are not unfrequently ramified, each branch or division terminating in a minute rudiment of an embryo. But as the lateral branches of the funiculi usually consist of a single elongated cell or vessel, while the principal or terminal branch is generally formed of more than one, embryos in Coniferæ may originate either in one or in several cells, even in the same funiculus. A similar ramification in the funiculi of the Cycas circinalis has been observed by the author. Instances of the occasional introduction of more than one embryo in the seeds of the several plants belonging to other families have long been known, but their constant plurality and regular arrangement have hitherto only been observed in Cycadeæ and Coniferæ."
