Mint and Thyme 283 
The rosy-flowered Henbit Dead-nettle (LZ. amplexi- 
caule) has a long slender tube, and its proper flowers 
appear from April to August ; but earlier in the spring, 
and again in autumn, it produces flowers that never 
open (cleistogamous). In these the style is doubled 
on itself because of the confined space, and the long 
stigma-lobes twist about among the anthers, getting 
fertilised by their pollen. The normal flowers also 
appear to favour self-fertilisation, but 1t 1s probable 
that they are often crossed, though insects cannot be 
seen around it inany numbers. The Red Dead-nettle 
(L. purpureum) has smaller flowers, in which the 
anthers and stigmas mature together, and both cross- 
and self- fertilisation ensues. The tube is shorter, 
so that bees with tongues of less length than those 
mentioned above can obtain the honey. 
Black Horehound (Lallota nigra) protects itself 
from herbivorous animals by an unpleasant odour cal- 
culated to produce feelings of nausea in any that bruise 
its stem or leaves. In truth, the old Greek name 
Ballota is said to be derived from ballo, to reject, 
because all animals refuse it as food. The upper lip 
of its tubular red-purple flowers is hairy within and 
without, and the lower one is marked with white 
honey-guide lines. The flower is visited by numerous 
insects in spite of the offensive smell; these are chiefly 
bees and butterflies, and they effect cross-fertilisation. 
Various species of flies also visit it, attracted doubt- 
less by the vile odour, but anxious to get their fill of 
the honey before they leave—a treat denied them by 
-a ring of hairs set around the tube in such wise that 
they cannot pass the expanded tip of their tongues 
through the circle. The pollen is discharged some- 
