[160]

Dionæa

young Leaf

[161]

Dionæa

young Leaf

(same scale no lettering) F. 186

(Dionæa muscipula: circumnutation of young leaf traced on horizontal glass in darkness, from 12 noon on Sept 24' to 10 am on 25th.─ Apex of leaf 13 1/2 inches beneath horizontal glass, so tracing much considerably magnified.

[161v]

95

Ipomoea Wait

Summary on the power of growth, vigour, and fecundity fertility of the successive generations of the crossed and self-fertilised plants of Ipomoea purpurea together with some miscellaneous observations.

In the following Table, No. 17, we see the average or mean heights of the ten successive generations of the intercrossed and self-fertilised plants of the present species, grown in competition with each other; and in the right hand column the ratio of the one to the other, the height of the intercrossed plants being taken at 100. In the bottom line, the average or mean height of the 73 intercrossed plants is shown to be 85.84 inches, and that of the 73 self-fertilised plants 66.02 inches, or as 100 to 77. (a) (see Back) This is represented in the accompanying diagram, in which the relative heights of the plants in each generation; and their mean height are shown) (Diagram) This difference in height between the crossed & self-fertilised plants be best appreciated by an illustration: if all the men in a country had were on an average height of 6 feet high, and