Chapter 4 - Page 2

LONG-STYLED, MID-STYLED, and SHORT-STYLED. The stamens also are of unequal lengths, and these may be called the LONGEST, MID-LENGTH, and SHORTEST. Two sets of stamens of different length are found in each form. The existence of the three forms was first observed by Vaucher, and subsequently more carefully by Wirtgen ; but these botanists, not being guided by any theory or even suspicion of their functional differences, did not perceive some of the most curious points of difference in their structure. (4/1. Vaucher 'Hist. Phys. des Plantes d'Europe' tome 2 1841 page 371. Wirtgen "Ueber Lythrum salicaria und dessen Formen" 'Verhand. des naturhist. Vereins fur preuss. Rheinl.' 5 Jahrgang 1848 S. 7.) I will first briefly describe the three forms by the aid of Figure 4.10, which shows the flowers, six times magnified, in their natural position, with their petals and calyx on the near side removed.

LONG-STYLED FORM.

This form can be at once recognised by the length of the pistil, which is (including the ovarium) fully one-third longer than that of the mid-styled, and more than thrice as long as that of the short-styled form. It is so disproportionately long, that it projects in the bud through the folded petals. It stands out considerably beyond the mid-length stamens; its terminal portion depends a little, but the stigma itself is slightly upturned. The globular stigma is considerably larger than that of the other two forms, with the papillae on its surface generally longer. The six mid-length stamens project about two-thirds the length of the pistil, and correspond in length with the pistil of the mid-styled form. Such correspondence in this and the two following forms is generally very close; the difference, where there is any, being usually in a slight excess of length in the stamens. The six shortest stamens lie concealed within the calyx; their ends are turned up, and they are graduated in length, so as to form a double row. The anthers of these stamens are smaller than those of the mid-length ones. The pollen is of the same yellow colour in both sets. H. Muller measured the pollen-grain in all three forms, and his measurements are evidently more trustworthy than those which I formerly made, so I will give them. (4/2. 'Die Befruchtung der Blumen' 1873 page 193.) The numbers refer to divisions of the micrometer equalling 1/300 millimetres. The grains, distended with water, from the mid-length stamens are 7 to 7 1/2, and those from the shortest stamens 6 to 6 1/2 in diameter, or as 100 to 86. The capsules of this form contain on an average 93 seeds: how this average was obtained will presently be explained. As these seeds, when cleaned, seemed larger than those from the mid-styled or short-styled forms, 100 of them were placed in a good balance, and by the double method of weighing were found to equal 121 seeds of the mid-styled or 142 of the short-styled; so that five long-styled seeds very nearly equal six mid-styled or