Gentian and Bogbean 235 
narrow corolla together exclude all but bees and 
lepidoptera whose tongues are long enough to reach 
the honey and at the same time effect cross-fertilisa- 
tion owing to the position of the essential organs. 
There is a pretty plant called Yellow-wort (Chlora 
perfoliata), that grows on downs, banks, and heaths, 
on a chalky or clay soil, of which perhaps the most 
striking feature is the perfect amalgamation of a 
pair of leaves by their lower edges (hence the name 
perfoliata, signifying that the stem passes through the 
leaf). The yellow flowers, however,are interesting, and 
may help to throw some hght upon the original form 
of the blossoms in the family. It is clearly distinct 
from our Gentians, yet it is not without suggestions of 
that Yellow Gentian to which I have referred. Its 
corolla is tubular at its base only, and above is split 
up into eight or six spreading lobes; there is an 
equal number of very slender sepals, and stamens to 
correspond. The stigma is cloven into two lobes, and 
to favour cross-fertilisation these mature before the 
pollen is shed; if, however, insect-visitors fail to 
arrive in time, self-fertilisation may be effected, but 
however fertilisation comes about, when completed 
the style is shed. It may be noted in passing that 
the object of the perfoliate leaves is to make it 
difficult for undesirable crawling insects to obtain 
access to the flowers by climbing the stem. 
A more noticeable plant by roadside and in dry 
pastures is the neat little Centaury (Lrythrea 
centawrium), with pink or red flowers, funnel-shaped, 
with a long cylindrical tube and four or five spreading 
lobes. There is a good deal of variation in the length 
of the tube, the proportionate length of the style, and 
