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Show 162 HETEROSTYLED TRIMORPHIC PLANTS. CHAP. IV. is that the mid -sty led form differs from both the others in its much higher capacity for fertilisation in various ways. Not only did the twenty-four flowers legitimately fertilised by the stamens of corresponding lengths, all, or all but one, yield capsules rich in seed; but of the other four illegiti1nate unions, that by the longest stamens of the short-sty led fo~U: was highly fertile, though less so than the two leg1t1mate unions, and that by the mid-length stamens of the long-styled form was fertile to a considerable degree; the remaining two illegitimate unions, namely, with this form's own pollen, were sterile, but in different degrees. So that the mid-styled form, when fertilised in the six different possible methods, evinces five grades of fertility. By comparing compartments III. and VI. in Table 24 we may see that the action of the pollen from the shortest stamens of the long-sty led and mid-styled forms is widely different; in the one case above half the fertilised flowers yielded capsules containing a fair number of seeds; in the other case not one capsule was produced. So, again, the green, large-grained pollen from the longest stamens of the short-styled and mid-styled forms (in compartInents IV. and V.) is widely different. In both these cases the difference in action is so plain that it cannot be mistaken, but it can be corroborated. If we look to rrable 25 to the legitimate action of the shortest stamens of the long- and mid -sty led forms on the short-styled form, we again see a similar but slighter difference, the pollen of the shortest stamens of the mid-styled form yielding a smaller average of seed during the two years of 1862 and 1863 than that from the shortest stamens of the long-sty led form. Again, if we look to Table 23, to the legitimate action on the Ion g-sty led form of the green pollen of the two CHAP. IV. LYTHRUM SALICARIA. 163 sets of longest stamens, we shall find exactly the same result, viz. that the pollen from the longest stamens of the mid-styled form yielded during both years fewer seeds than that from the longest stamens of the short-styled form. Hence it is certain that the two kinds of pollen produced by the mid-styled form are less potent than the two similar kinds of pollen produced by the corresponding stamens of the other two forms. In close connection with the lesser potency of the two kinds of pollen of the mid-styled form is the fact that, according to H. Muller, the grains of both are a little less in diameter than the corresponding grains produced by the other two forms. Thus the grains from the longest stamens of the mid -sty led form are 9 to 10, whilst those from the corresponding stamens of the short-styled form are 9! to 10~ in diameter. So, again, the grains from the shortest stamens of the mid-styled are 6, whilst those from the corresponding stamens of the long-styled are 6 to 6! in diameter. It would thus appear as if the male organs of the mid-styled form, though not as yet rudimentary, were tending in this direction. On the other hand, the female organs of this form are in an eminently efficient state, for the naturally fertilised capsules yielded a considerably larger average number of seeds than those of the other two forms-almost every flower which was artificially fertilised in a legitimate manner produced a capsule-and most of the illegitimate unions were highly productive. The mid-styled form thus appears to be highly feminine in nature; and although, as just remarked, it is impossible to consider its two well-developed sets of stamens which produce an abundance of pollen as being in a rudimentary condition, yet we can hardly avoid connecting as M 2 |