3.  Gesneriaceae.—­Gesneria pendulina.

In Gesneria the several parts of the flower are arranged on nearly the same plan as in Digitalis, and most or all of the species are dichogamous. (3/11.  Dr. Ogle ‘Popular Science Review’ January 1870 page 51.) Plants were raised from seed sent me by Fritz Muller from South Brazil.  Seven flowers were crossed with pollen from a distinct plant, and produced seven capsules containing by weight 3.01 grains of seeds.  Seven flowers on the same plants were fertilised with their own pollen, and their seven capsules contained exactly the same weight of seeds.  Germinating seeds were planted on opposite sides of four pots, and when fully grown measured to the tips of their leaves.

Table 3/26.  Gesneria pendulina.

Heights of Plants measured in inches.

Column 1:  Number (Name) of Pot.

Column 2:  Crossed Plants.

Column 3:  Self-fertilised Plants.

Pot 1 :  42 2/8 :  39. 
Pot 1 :  24 4/8 :  27 3/8.

Pot 2 :  33 :  30 6/8. 
Pot 2 :  27 :  19 2/8.

Pot 3 :  33 4/8 :  31 7/8. 
Pot 3 :  29 4/8 :  28 6/8.

Pot 4 :  30 6/8 :  29 6/8. 
Pot 4 :  36 :  26 3/8.

Total :  256.50 :  233.13.

The average height of the eight crossed plants is 32.06 inches, and that of the eight self-fertilised plants 29.14; or as 100 to 90.

4.  Labiatae.—­Salvia coccinea. (3/12.  The admirable mechanical adaptations in this genus for favouring or ensuring cross-fertilisation, have been fully described by Sprengel, Hildebrand, Delpino, H. Muller, Ogle, and others, in their several works.)

This species, unlike most of the others in the same genus, yields a good many seeds when insects are excluded.  I gathered ninety-eight capsules produced by flowers spontaneously self-fertilised under a net, and they contained on an average 1.45 seeds, whilst flowers artificially fertilised with their own pollen, in which case the stigma will have received plenty of pollen, yielded on an average 3.3 seeds, or more than twice as many.  Twenty flowers were crossed with pollen from a distinct plant, and twenty-six were self-fertilised.  There was no great difference in the proportional number of flowers which produced capsules by these two processes, or in the number of the contained seeds, or in the weight of an equal number of seeds.

Seeds of both kinds were sown rather thickly on opposite sides of three pots.  When the seedlings were about 3 inches in height, the crossed showed a slight advantage over the self-fertilised.  When two-thirds grown, the two tallest plants on each side of each pot were measured; the crossed averaged 16.37 inches, and the self-fertilised 11.75 in height; or as 100 to 71.  When the plants were fully grown and had done flowering, the two tallest plants on each side were again measured, with the results shown in Table 3/27.