OF PLANTS. 
195 
in such a manner as to shelter the young stems, buds, oi 
fruit. They turn up, or they fall down, according as this 
purpose renders either change or position requisite. In 
the growth of corn, whenever the plant begins to shoot, the 
two upper leaves of the stalk join together, embrace the 
ear, and protect it till the pulp has acquired a certain de¬ 
gree of consistency. In some water plants, the flowering 
and fecundation are carried on within the stem, which af¬ 
terwards opens to let loose the impregnated seed.* The 
pea or papilionaceous tribe, enclose the parts of fructifi¬ 
cation within a beautiful folding of the internal blossom, 
sometimes called, from its shape, the boat or keel; itself 
also protected under a penthouse formed by the external 
petals. This structure is very artificial; and what adds to 
the value of it, though it may diminish the curiosity, very 
general. It has also this farther advantage, (and it is an 
advantage strictly mechanical,) that all the blossoms turn 
their backs to the wind, whenever the gale blows strong 
enough to endanger the delicate parts upon which the seed 
depends. I have observed this a hundred times in a field 
of peas in blossom. It is an aptitude which results from 
the figure of the flower, and, as we have said, is strictly 
mechanical; as much so as the turning of a weather-board 
or tin cap upon the top of a chimney. Of the poppy, and 
of many similar species of flowers, the head, while it is 
growing, hangs down, a rigid curvature in the upper part 
of the stem giving to it that position; and in that position 
it is impenetrable by rain or moisture. When the head 
has acquired its size, and is ready to open, the stalk erects 
itself, for the purpose, as it should seem, of presenting the 
flower, and with the flower, the instruments of fructifica¬ 
tion, to the genial influence of the sun’s rays. This al¬ 
ways struck me as a curious property; and specifically as 
well as originally, provided for in the constitution of the 
plant; for, if the stem be only bent by the weight of the 
head, how comes it to .straighten itself when the head is 
the heaviest? These instances show the attention of na¬ 
ture to this principal object, the safety and maturation of 
the parts upon which the seed depends. 
In trees, especially in those which are natives of colder 
climates, this point is taken up earlier. Many of these trees 
(observe in particular the ash and the horse-chestnut ) pro- 
upon this phenomenon, because, in the cold, leaves awaken later, and 
fall more easily asleep, notwithstanding the influence of light.” Vide 
Elements of the Philosophy of Plants by Decandolle.— Paxton. 
* Phil. Trans, part ii. 1796; p. 502. 
