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Show 320 CLEISTOGAMIC FL9WERS. CHAP. VIII. last species; but no perfect ones were produced. Mr. Scott informs me that in India it bears perfect flowers only during the cold season, and that these are quite fertile. During the hot, and more especially during the rainy season, it bears an abundance of cleistogamic flowers. Many other species, besides the five now described, produce cleistogamic flowers; this is the case, according to D. Muller, Michalet, Von Mohl, and Hermann Muller, with V. elatior, lancifolia, sylvatica, palustris, mirabilis, bicolor, ionodium, and biflora.. But V. tricolor does not produce them. Michalet asserts that V. palustris produces near Paris only perfect flowers, which are quite fertile; but that when the plant grows on mountains cleistogamic flowers are produced; and so it is with V. bijlora. The same author states that he has seen in the ca~e of V. alba flowers intermediate in structure between the perfect and cleistogamic ones. According to M. Boisduval, an Italian species, V. Ruppii, never bears in France "des fleurs bien apparentes, ce qui ne l'em-peche pas de fructifier." . . It is interesting to observe the gradation In the abortion of the parts in the cleistogamic flowers of the several foreo-oin()" species. It appears from the statements by D~ Muller and Von Mohl that in V. mirabilis the calyx does not remain quite closed; all five stamens are provided with anthers, and some p~llengrains probably fall out of the cells on the stigma, instead of protruding their tubes whilst still enclosed, as in the other species. In V. hirta all five stamens are likewise an theriferous ; the petals are . noJ so much reduced and the pistil not so much Inodifi~ as in the following species. In V. nana and elatwr only two of the stamens properly bear anthers, but CHAP. VIII. OXALIS. 321 sometimes one or even two of the others are thus provided. Lastly, in V. canina never more than two of the stamens, as far as I have seen, bear anthers; the petals are much more reduced than in V. hirta, and according to D. Muller are sometimes quite absent. Ortalis acetosella.-The existence of cleistogamic flowers on this plant was discovered by Michalet.* They have been fully described by Von Mohl, and I can add hardly anything to his description. In my specimens the anthers of the five longer stamens were nearly on a level with the stigmas; whilst the smaller and less plainly bilobed anthers of the :five shorter stamens stood considerably below the stigmas so that thei~ tubes h~d to travel some way upwards. According to M1chalet these latter anthers are sometimes quite aborted. In one case the tubes which ended .in excessively :fine points, were seen 'by me stretc~Ing upwards from the lower anthers toward the stigmas, which they had not as yet reached. My plants. grew in pots, and long after the perfect flowers had With.ered they produced not only cleistogamic but a fe~ minute .open flowers, which were in an intermediate condition between the two kinds. In one of these the pollen-tubes from the lower anthers had ~~Z7d the stigmas, th~ugh the flower was open. h ootstalks of the cleistoganlic flowers are much ~~r~e~ than those of the perfect flowers, and are so V c owed downwards that they tend, according to 1 on Mohl, to bury themselves in the moss and dead eaves on the ground M' h 1 are often h . . Ic a et also says that they ber f d ypogean. In order to ascertain the num-of t~e~e~ t pr~d.uced by these flowers, I marked eight ' ~o ailed, one cast its seed abroad, and the * 'Bull S , oc. Bot. de France,' tom. vii. 1860, p. 465. y |