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Show 188 ILLEGITIMATE OFFSPRING OF CHAP. v. CHAPTER V. ILLEGITIMATE 0FFSP1UNG OF fiETEROSTYLED PLANTS. Illegitimate offspring from all three forms of Lythrum salicaria-~heir dwarfed stature and sterility, some 'htterly barren, some fertlleOxalis, transmission of form to the legitimate and illegitimate seedlings-Primula Sinensis, illegitimat~ ~ffspring in. som~ degrc~e dwarfed and infertile-Equal-styled vanetres of P. Smens1s, auncula farinosa and elatior-P. vulgaris, red-flowered variety, illcgitim; te seedli~gs sterile-P. veris, illegitimate plants raised ~~ring several successive generations, their dwarfed stature and stenhtyEqual- styled varieties of P. veris-Transmission of form by ~ulmonaria and Polygonum-Concluding remarks-Close parallelism between illegitimate fertilisation and hybridism. WE have hitherto treated of the fertility of the flowers of heterostyled plants, when legitimately and illegitimately fertilised. The present chapter will be devoted to the character of their offspring or seedlings. rrhose raised from legitimately fertilised seeds will be here called legitirnate seedlings or plants, and those from illegitimately fertilised seeds, illegitimate seedlin~s. or plants. They differ chiefly in their degree of !ertilit!, and in their powers of growth or vigour. I will begin with trimorphic plants, and I must remind the read~r that each of the three forms can be fertilised in SIX different ways; so that all three together can be fertilised in eighteen different ways. For instance, a long-styled form can be fertilised legitimately by the longest stamens of the n1id-styled and short-stylet! forms, and illegitimately by its own-form mid-length and shortest stamens, also by the mid-length stamens of the mid -sty led and by the shortest sta1nens of th.e short-styled form; so that the long:-styled can be fertl· CHAP. V. HETEROSTYLED TRIMORPHIC PLANTS. 189 Iised legitimately in two ways and illegitimately in four ways. The same holds good with respect to the mid-styled and short-styled forms. Therefore with trimorphic species six of the eighteen unions yield legitimate offspring, and twelve yield illegitimate offspring. I will give the results of my experiments in detail, partly because the observations are extremely troublesome, ancl will not probably soon be repeated-thus, I was compelled to count under the 1nicroscope above 20,000 seeds of Lythrum salicaria-but chiefly bec~use light is thus indirectly thrown on the important subject of hybridism. LYTHRUM SALIQARIA. Of the twelve illegitimate unions two were completely barren, so that no seeds were obtained, and of course no seedlings could be raised. Seedlings were, however raised from seven of the ten ro1naining illegitimate unions. Such illegitimate seedlings when in flower were generally allowed to be free I y and legitimately fertilised, through the agency of bees, by other illegiti1nate plants belonging to the two other forms growing close by. This is the fairest plan, ~nd was usually followed; but in several cases ( wh1c~ will always be stated) illegitimate plants were fertilised with pollen taken from legiti1nate plants belono ·ino- to the other two forms ; and this, as might havoe bbe en expected, increased their fert1· 11· ty. L yt hr u.m salicaria is much affected in its fertility by the nature of the season · and to a void errol' from this source, as far as pos;ible, my observations were continued during several· years. Some few experiments were ti·ied in 1863. The summer of 1864 was too hot and |