XIV 
FUNDAMENTAL PROBLEMS 
429 
Commencing with the origin of the flower, which all botanists 
agree in regarding as a shortened branch, he explains this 
shortening as an inevitable physiological fact, since the cost of 
the development of the reproductive elements is so great as 
necessarily to check vegetative growth. In the same manner 
the shortening of the inflorescence from raceme to spike or 
umbel, and thence to the capitulum or dense flower-head 
of the composite plants is brought about. This shortening, 
carried still further, produces the flattened leaf-like receptacle 
of Dorstenia, and further still the deeply hollowed fruity 
receptacle of the fig. 
The flower itself undergoes a parallel modification due to a 
similar cause. It is formed by a series of modified leaves 
arranged round a shortened axis. In its earlier stages the 
number of these modified leaves is indefinite, as in many 
Ranunculacese; and the axis itself is not greatly shortened, as 
in Myosurus. The first advance is to a definite number of 
parts and a permanently shortened axis, in the arrangement 
termed hypogynous, in which all the whorls are quite distinct 
from each other. In the next stage there is a further shorten¬ 
ing of the central axis, leaving the outer portion as a ring on 
which the petals are inserted, producing the arrangement 
termed perigynous. A still further advance is made by the 
contraction of the axis, so as to leave the central part form¬ 
ing the ovary quite below the flower, which is then termed 
epigynous. 
These several modifications are said to be parallel and 
definite, and to be determined by the continuous checking of 
vegetation by reproduction along what is an absolute groove 
of progressive change. This being the case, the importance of 
natural selection is greatly diminished. Instead of selecting 
and accumulating spontaneous indefinite variations, its function 
is to retard them after the stage of maximum utility has been 
independently reached. The same simple conception is said 
to unlock innumerable problems of vegetable morphology, large 
and small alike. It explains the inevitable development of 
gymnosperm into angiosperm by the checked vegetative growth 
of the ovule-bearing leaf or carpel; while such minor adapta¬ 
tions as the splitting fruit of the geranium or the cupped stigma 
of the pansy, can be no longer looked upon as achievements 
