HABITS OF PLANTS. 
263 
white. It begins to open about seven or eight o’clock in the 
evening, and closes before sunrise in the morning. • 
“ The flower of the dandelion possessses very peculiar means 
of sheltering itself from the heat of the sun, as it closes entirely 
whenever the heat becomes excessive. It has been observed to open 
in summer at half an hour after five in the morning, and to col- 
lect its petals towards the centre about nine o’clock.” 
Linnaeus has enumerated forty-six flowers which possess this 
kind of sensibility : he divides them into three classes. 
1. Meteoric flowers, which less accurately observe the hour 
of folding, but are expanded sooner or later, according to 
the cloudiness, moisture, or pressure of the atmosphere. 
2. Tropical flowers, that open in the morning, and close before 
evening every day, but the hour of their expanding becomes 
earlier or later, as the length of the day increases or de- 
creases. 
3. Equinoctial flowers, which open at a certain and exact hour 
of the day, and for the most part close at another deter- 
minate hour.* 
LECTURE XLI. 
Habits of plants. — Agents which affect their growth. Their 
habitations, and geographical situations. — Elevation corres- 
ponding to latitude. 
The constitutions of plants and that of animals seem to fit 
them for particular climates and for digesting food of a certain 
kind. The plant cannot like the animal rove about in search of 
food best suited to its nature, but fixed in one spot, must receive 
the nourishment that there offers itself. If this nourishment 
is too abundant, the vessels becoming loaded with excess, cease 
to perform their accustomed functions, and the plant dies of 
surfeit ; if on the other hand the food offered is too little or not 
sufficiently nourishing, the plant dies of starvation. 
Yet plants may be brought to live in climates, and on food 
not naturally suited to their constitutions ; or in other words 
their habits may be changed. Although we may suppose that 
many things now necessary to our comfort and even our lives, 
are rendered so by nature ; yet if we reflect a moment we shall 
* Bacon. 
Meteoric flowers — Tropical, Equinoctial. 
The constitution of plants fitted for particular climates. 
