354 
DIAL OF FLOWERS. 
fructification, and to protect them from the 
pernicious influence of external agents. Those 
organs of fructification are the chief objects of 
the maternal care of Nature ; while shut up in 
the flower-hud, they acquire that strength and 
perfection of parts which enable them to en¬ 
dure the light of the sun, and to perform the 
functions for which they are designed. It is 
not till they are capable of fulfilling these func¬ 
tions that the flower unfolds itself; but it 
again closes at such times when external influ¬ 
ences might be injurious to the delicate organs 
of fructification. Many flowers can bear only the 
refreshing morning air and the first rays of the 
sun, but remain shut all the rest of the day. 
This may be particularly observed in the dif¬ 
ferent species of Convolvulus, Ipomasa, and 
Goat’s Beard. We find these in general open 
only till about eleven o’clock. In like manner, 
the Mallows and the Mesembryanthemums un¬ 
fold their flowers about noon ; and precisely at 
that time, in serene weather, open the singu¬ 
larly formed Drosera, and the common Purslain, 
which shut again in an hour. Others unfold 
themselves only in the evening, and continue 
