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Show 98 HETEROSTYLED Dil\10RPHIO PLANTS. CHAP. III. with papillre with their heads already charged with pollen from' the stamens of corresponding .h.eight borne by the flowers of the other form, and legitimate fertilisation is thus ensured. Thus we can understand the meaning of the torsion of the styles in the long-sty led flowers alone, as well as their divergence in the short-styled flowers. One other point is worth notice. In botanical works n1any flowers are said to be fertilised in the ?ud. This statement generally rests, as far as I can discovEr, on the anthers opening in the bud; no evidence being adduced that the stigma is at this period 1nature, or that it is not subsequently acted on by pollen brought frmn other flowers. In the case of Oephalanthera grandiflora I have shown* that precocious and partial Relf-fertilisation, with subsequent full fertilisation, is the regular course of events. The belief that the flowers of many plants are fertilised in the bud, that is, are perpetually self-fertilised, is a n1ost effectual bar to understanding their real structure. I an1, however, far from wishing to assert that some flowers, during certain seasons, are not fertilised in the bud ; for I have reason to believe that this is the case. A good observer, t resting his belief on the usual kind of evidence, states that in Linum Austriacum (which is heterosty led, and is considered by Planchon as a variety of L. perenne) the anthers open the evening before the expansion of the flowers, and that the stigmas are then almost always fertilised. Now we know positively that, so far from Linum perenne being fertilised by its own pollen in the bud, its own pollen is as powerless on the stign1a as so much inorganic dust. Linu1n flavum.-The pistil of the long-sty led form * 'Fertili at ion of Orchid:;,' t ' Etudes sur la Geogr. Bot.,' p. 108:-2nd edit. 1877, p. 84. H. Lecoq, 1856, tom. v. p. 025. CHAP. III. LINUM FLA VUM. 99 of this species is nearly twice as I ng as that of the short-sty led ; the stigmas are longer and the papilloo coarser. In the short-sty led form the stigmas diverge and pass out between the :filam nts, as in the previous species. The stamens in the two forms differ in length; and, what is singular, the anthers of the longer sta1nens are not so long as those of the other form; so that in the short-styled form both the stigmas and the anthers are shorter than in the long-styled form. The pollen -grains of the two forms do not differ in size. As this species is propagated by cuttings, generally all the plants in the same garden belong to the same form. I have inquired, but have never heard of its seeding in this country. Certainly my own plants never produced a single seed as long as I possessed only one of the two forms. After considerable search I procured both forms, but from want of time only a few experiments were made. Two plants of the two forms were planted some way apart in my garden, and were not covered by nets. Three flowers on the long-sty led plant were legitimately fertilised with pollen from the short-sty led plant, and one of them set a fine capsule. No other capsules were produced by this plant. Three flowers on the short-sty led plant were legitimately fertilised with pollen from the long-styled, and all three produced capsules, containing respectively no less than 8, 9, and 10 seeds. Three other flowers on this plant, which had not been artificially fertilisecl, produced capsules containing 5, 1, and 5 seeds; and it is quite possible that pollen may have been brought to them by insects from the long-sty led plant growing in the same garden. Nevertheless, as they d~d not yield half the number of seeds compared With the other flowers on the same plant which had been artificjally a~d legitimately fertilised, and as the Jl 2 |