29G 
S^idl of jFlolmrs. 
and Goat's Beard. We find these, in general, open only 
till about eleven o'clock. In like manner, the Mallows 
and the IMesembryanthemums unfold their flowers 
about noon: and precisely at that time, in serene 
weather, open the singularly- formed Drosera, and the 
common Purslain, which shut again in an hour. 
Others unfold themselves only in the evening, and con- 
tinue open all night, probably because their delicate 
organs would be injured by the sun. The CEnotheras, 
the Gauras, and the different species of the Mirabilis, 
furnish examples of this kind. Thus, too, the Cactus 
opuntia opens its magnificent blossoms at night only, 
and towards morning shuts them up for ever. Tlie 
flowers of many plants of the nineteenth class are ob- 
served to hang their heads during night — the Cami-HIa, 
for example — by which means the rain, or dew, which 
might injure the tender organs of fructification, can run 
off the more easily. In other plants of this class, the 
flower shuts up against rain, and on the approach of 
evening, as is the case with the Marigolds. 
The periodical change of colour in some flowers is 
also worthy of remark. Thus, the flowers of the 
speckled French Honeysuckle [Hedysarummaculatum) 
are purple in the morning and green at noon. Tlie 
changeable Hibiscus {Hihisciis mutabilis) is white in 
the morning, flesh-coloured at noon, and rose-red in the 
evening. Thus, too, the great Corn-flag {Gladiolus 
yrandis) changes its colour several times in the course 
of the day. 
Neither is the scent of flowers equally strong and 
agreeable at all hours of the day: many, even of our 
indigenous flowers, have the strongest scent at night. 
