the whorls, R. Brown offers no sufficient evidence, but believes that they are combined with the labellum, whenever that organ presents crests or ridges. In these views Brown is followed by Lindley.[1]
Brown traced the spiral vessels in the flower by making transverse sections,[2] and only occasionally, as far as it appears, by longitudinal sections. As spiral vessels are developed at a very early period of growth, and this circumstance always gives much value to a part in making out homologies; and as they are apparently of high functional importance, though their function is not well known, it appeared to me, guided also by the advice of Dr. Hooker, to be worth while to trace upwards all the spiral vessels from the six groups surrounding the ovarium. Of the six ovarian groups of vessels, I will call (though not correctly) that under the labellum the anterior group; that under the upper sepal the posterior group; and the two groups on the two sides of the ovarium the antero-lateral and postero-lateral groups.
The result of my dissections is given in the following diagram (fig. 36). The fifteen little circles represent
- ↑ Professor Asa Gray has described in the 'American Journal of Science,' July 1866, a monstrous flower of Cypripedium candidum, and remarks on it, "here we have (and perhaps the first direct) demonstration that the orchideous type of flower has two staminal verticils, as Brown always insisted." Dr. Crüger also advances evidence ('Journ. Linn. Soc. Bot.' vol. viii. 1864:, p. 132) in favour of the presence of five whorls of organs; but he denies that the homologies of the parts can be deduced from the course of the vessels, and he does not admit that the labellum is formed by the union of one petal with two petaloid stamens.
- ↑ 'Linn. Transact.' vol. xvi. p. 696–701. Link in his 'Bemerkungen über der Bau der Orchideen' ('Botanische Zeitung,' 1849, p. 745) seems to have also trusted to transverse sections. Had he traced the vessels upwards I cannot believe that he would have disputed Brown's view of the nature of the two anthers in Cypripedium. Brongniart in his admirable paper ('Annales des Sciences Nat.' tom. xxiv. 1831) incidentally shows the course of some of the spiral vessels.
