TABLE 5/68. Lobelia ramosa (First Generation).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Tallest Crossed Plant in each Pot.
Column 3: Tallest Self-fertilised Plant in each Pot.
Pot 1 : 22 4/8 : 17 4/8.
Pot 2 : 27 4/8 : 24.
Pot 3 : 16 4/8 : 15.
Pot 4 : 22 4/8 : 17.
Total : 89.0 : 73.5.
The four tallest crossed plants averaged 22.25, and the four tallest self-fertilised 18.37 inches in height; or as 100 to 82. I was surprised to find that the anthers of a good many of these self-fertilised plants did not cohere and did not contain any pollen; and the anthers even of a very few of the crossed plants were in the same condition. Some flowers on the crossed plants were again crossed, four capsules being thus obtained; and some flowers on the self-fertilised plants were again self-fertilised, seven capsules being thus obtained. The seeds from both lots were weighed, and it was calculated that an equal number of capsules would have yielded seed in the proportion by weight of 100 for the crossed to 60 for the self-fertilised capsules. So that the flowers on the crossed plants again crossed were much more fertile than those on the self-fertilised plants again self-fertilised.
PLANTS OF THE SECOND GENERATION.
The above two lots of seeds were placed on damp sand, and many of the crossed seeds germinated, as on the last occasion, before the self-fertilised, and were rejected. Three or four pairs in the same state of germination were planted on the opposite sides of two pots; a single pair in a third pot; and all the remaining seeds were sown crowded in a fourth pot. When the seedlings were about one and a half inches in height, they were equal on both sides of the three first pots; but in Pot 4, in which they grew crowded and were thus exposed to severe competition, the crossed were about a third taller than the self-fertilised. In this latter pot, when the crossed averaged 5 inches in height, the self-fertilised were about 4 inches; nor did they look nearly such fine plants. In all four pots the crossed plants flowered some days before the self-fertilised. When in full flower the tallest plant on each side was measured; but before this time the single crossed plant in Pot 3, which was taller than its antagonist, had died and was not measured. So that only the tallest plant on each side of three pots was measured, as in Table 5/69.
TABLE 5/69. Lobelia ramosa (Second Generation).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Tallest Crossed Plant in each Pot.
Column 3: Tallest Self-fertilised Plant in each Pot.
Pot 1 : 27 4/8 : 18 4/8.
Pot 2 : 21 : 19 4/8.
Pot 3 : 21 4/8 : 19. Crowded.
Total : 70 : 57.
The average height of the three tallest crossed plants is here 23.33, and that of the tallest self-fertilised 19 inches; or as 100 to 81. Besides this difference in height, the crossed plants were much more vigorous and more branched than the self-fertilised plants, and it is unfortunate that they were not weighed.
Lobelia fulgens.
This species offers a somewhat perplexing case. In the first generation the self-fertilised plants, though few in number, greatly exceeded the crossed in height; whilst in the second generation, when the trial was made on a much larger scale, the crossed beat the self-fertilised plants. As this species is generally propagated by off-sets, some seedlings were first raised, in order to have distinct plants. On one of these plants several flowers were fertilised with their own pollen; and as the pollen is mature and shed long before the stigma of the same flower is ready for fertilisation, it was necessary to number each flower and keep its pollen in paper with a corresponding number. By this means well-matured pollen was used for self-fertilisation. Several flowers on the same plant were crossed with pollen from a distinct individual, and to obtain this the conjoined anthers of young flowers were roughly squeezed, and as it is naturally protruded very slowly by the growth of the pistil, it is probable that the pollen used by me was hardly mature, certainly less mature than that employed for self-fertilisation.