CHAPTER VI 
TROPOPHYTES 
We live in a country subject to changing seasons. Winter 
follows summer, but in neither case are the conditions 
extreme. During the summer any interruption caused 
by drought is only partial and transitory. The fields 
may become parched and the grass brown, but little else 
suffers. In other countries where the summer is very 
dry, the break begins at the onset of the greatest heat. 
Our winters, too, are mild, frosts being intermittent 
and seldom lasting long. For this reason we are never 
utterly without flowers. A few hardy stragglers, sur- 
viving in sheltered places, bloom in November (purple 
deadnettle, Euphorbia Peplis, Stachys arvensis), while 
the first pioneers of spring bloom soon after Christmas 
(Christmas-rose, snowdrop, winter-aconite). The gorse 
is found in bloom nearly all the year ; it starts flowering 
after Christmas, and goes on till the middle of summer ; 
it flowers again inthe autumn. Apart from this, however, 
the frequently low temperature and the prevalence of 
strong winds, often from the east, make the winter- 
break, even in England, serious for the greater part of the 
vegetation. For four to five months there is a marked 
period of rest, during which most of the vegetation is in 
a hibernating condition. 
Now, there are two ways by which plants may meet 
- the winter : 
1. They may possess permanent adaptations providing 
against the physiological drought of winter. These are 
evergreen xerophytes, bearing throughout the summer an 
equipment which is most useful only in winter (see p. 30). 
2. They may discard all or part of their summer char- 
acters at the close of the vegetative season, assuming a 
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