Note M — OBSERVATIONS ON THE POLLINATION Of Solanum rostratum Dunal and Cassia chamæcrista L.

It must be stated that in a later paper (Robertson, Charles: Flowers and Insects, V. Bot. Gaz., vol. XV, No. 8, pp. 199-204), Charles Robertson does not give the same results as those found by Thomas Meehan. Robertson says: “Two long stamens, one on each side of the style, furnish pollen for cross-fertilization. They have inflated anthers which probably have a bellows-like action, like the long stamen of Solanun rostratum and Rhexia virginica.” Meehan states expressly in his paper that in the case of C. marilandica he was sure no pollen was ejected, as Todd found for S. rostratum, since in the flowers, which were covered with a gauze bag, the membrane at the apex was never ruptured when the stamens were ready to fall. Robertson describes the method of extracting the pollen in C. chamæcrista in a way which is essentially the same as Todd gives for S. rostratum. He then says, in speaking of C. marilandica: “Four small stamens furnish pollen for the visitors. Bumblebees milk the pollen out of these, using their jaws, as in the case of chamæcrista.” Meehan says: “Nor was there any draw-out of the pollen, as observed by Professor Todd. It is abstracted solely through the pores; and, although I could see no evidence that such was actually the case, I suspect that fertilization could only occur through some of this extracted pollen escaping from the insect to the stigma.” It must be noted here that the method which Meehan describes for the method of opening of the anthers, the pollen being “abstracted solely through the pores,” does not agree with the method described by other observers. Leclerc du Sablon, in a paper, “Recherches sur la Structure et la Dehiscence des Anthers,” in vol. I of the seventh series of Annales des Sciences Nouvelles, discusses the anatomical modifications of the anther walls, by which dehiscence is secured. His observations cover Cassia cremophilia and Solanum. His observations do not cover a sufficient number of species to make them of the greatest value in deciding the present points. The author presents, in a condensed form, his results in: Note sur la Dehiscence des Anthers, La Belgique Horticole, vol. XXXIV, pp. 148-150, 1884. Robertson says, in speaking of the central of the three long stamens: “Bees, no doubt, force the pollen out of this as they do from the short stamens.” Meehan says: “I watched a mass of plants containing eighty-eight flower-stems on the 30th of July, and the same lot for an hour on the 6th of August, but saw no attempt to get pollen from the longer anthers or to use them in any way but as a platform. It would indeed be hardly possible for the bee to stand anywhere so as to get power to pierce the apical membranes of the longer stamens. When the flower matured and the anthers were ready to fall they were examined-the four short ones were empty sacs-the three lower ones proved that they had not served any purpose to the bees, for they were full of pollen.”