THE WHITE VERATRUM 123 



the seedlings of the British Cuckoo Pint {Arum 

 maculatum, Linn.) have been observed to be dragged 

 downwards a distance of 2 inches between May and 

 October. 



It is impossi])le to attempt to explain here the 

 mechanism whereby the contraction is effected. To 

 do so would involve a detailed account of the internal 

 structure and functions of the root. It may, however, 

 be said, that certain internal cells have the power 

 of contracting, and when this tissue shrinks it 

 shortens the external tissues, which no longer fit it, 

 but are drawn into wrinkles, like a glove too long for 

 the finger. It is naturally important that the under- 

 ground stem, as it increases in size, should be buried 

 deeper and deeper in the soil, to escape the frosts of 

 winter, and it is by the contraction of these roots; 

 that this is effected. 



The flowers of Veratrum are interesting from the 

 fact that while those of the main flowering shoot 

 usually contain both sexes (hermaphrodite), the flowers 

 of the lateral branches are generally male only. In 

 the plant figured on Plate XXVIL, Fig. 2, it was 

 found that thirty-two hermaphrodite flowers occurred 

 on the main axis, against forty-nine male flowers on 

 the lateral branches. We have already noticed in 

 the case of the Alpine Anemone, p. 39, that male 

 flowers are often more alnmdant than hermaphrodite. 

 Occasionally in Yeratrum, some of the upper flowers 

 are entirely female, without any trace of stamens. 



The flowers of Veratrum are often wholly green. 



