Chapter 3 - Page 2

and grew to a greater height than the other varieties; it likewise became more highly self-fertile, so that this variety resembles the plant named Hero, which appeared in the sixth self-fertilised generation of Ipomoea.

Some flowers on one of the plants raised from the purchased seeds were fertilised with their own pollen; and others on the same plant were crossed with pollen from a distinct plant. The seeds from twelve capsules thus produced were placed in separate watch-glasses for comparison; and those from the six crossed capsules appeared to the eye hardly more numerous than those from the six self-fertilised capsules. But when the seeds were weighed, those from the crossed capsules amounted to 1.02 grain, whilst those from the self-fertilised capsules were only .81 grain; so that the former were either heavier or more numerous than the latter, in the ratio of 100 to 79.

CROSSED AND SELF-FERTILISED PLANTS OF THE FIRST GENERATION.

Having ascertained, by leaving crossed and self-fertilised seed on damp sand, that they germinated simultaneously, both kinds were thickly sown on opposite sides of a broad and rather shallow pan; so that the two sets of seedlings, which came up at the same time, were subjected to the same unfavourable conditions. This was a bad method of treatment, but this species was one of the first on which I experimented. When the crossed seedlings were on an average half an inch high, the self-fertilised ones were only a quarter of an inch high. When grown to their full height under the above unfavourable conditions, the four tallest crossed plants averaged 7.62, and the four tallest self-fertilised 5.87 inches in height; or as 100 to 77. Ten flowers on the crossed plants were fully expanded before one on the self-fertilised plants. A few of these plants of both lots were transplanted into a large pot with plenty of good earth, and the self-fertilised plants, not now being subjected to severe competition, grew during the following year as tall as the crossed plants; but from a case which follows it is doubtful whether they would have long continued equal. Some flowers on the crossed plants were crossed with pollen from another plant, and the capsules thus produced contained a rather greater weight of seed than those on the self-fertilised plants again self-fertilised.

CROSSED AND SELF-FERTILISED PLANTS OF THE SECOND GENERATION.

Seeds from the foregoing plants, fertilised in the manner just stated, were sown on the opposite sides of a small pot (1) and came up crowded. The four tallest crossed seedlings, at the time of flowering, averaged 8 inches in height, whilst the four tallest self-fertilised plants averaged only 4 inches. Crossed seeds were sown by themselves in a second small pot, and self-fertilised seeds were sown by themselves in a third small pot so that there was no competition whatever between these two lots. Nevertheless the crossed plants grew from 1 to 2