ORGANS OF FRUCTIFICATION. 
65 
Some plants creep by their tendrils to a very great height, even to 
the tops of the loftiest trees, and seem to cease ascending, only be- 
cause they can find nothing higher to chmb. One of our most beau- 
tiful cUmbing plants is the clematis virginica, or virgin's bower, 
which has flowers of a brilhant whiteness. Its pericarps, richly 
fringed, are very conspicuous in autumn, hanging in festoons from 
the branches of trees, by the sides of brooks and rivers. 
8th. Pubescence includes the down, hairs, woolliness, or silkinessof 
plants. The pubescence of plants varies in different soils, and with 
different modes of cultivation. The species in some genera of plants 
are distinguished by the direction of the hairs. The microscope is 
often necessary in determining with precision, the existence and dir 
rection -of the pubescence. It has been suggested that these appen- 
dages may be for similar purposes as the fur, hair, and bristles of 
animals, viz. to defend the plants from cold, and injuries from other 
. causes. 
Fig. 66. 9th. The Bract, or floral leaf, is situated 
among, or near the flowers, and is different 
from the leaves of the plant. You may, in 
Fig. 66, observe the difference between the 
real leaves (&, b,) and the bract (a;) the 
former being cordate and crenate, the latter 
lanceolate and entire. 
In some plants, as in several species of 
sage, the transition from leaves to bracts is 
so gradual, as to render it difficult to distin- 
guish between- them, and a considerable part 
of the fohage is composed of the bracts. In 
the crown -imperial, the stem is terminated 
by a number of large and conspicuous bracts. 
These appendages are sometimes mistaken 
for the calyx. Bracts are green or coloured, 
deciduous or persistent. The orchis tribe 
have green leaf-bracts. No plants of the 
class Tetr adynamia have bracts. 
We have, in regular order, considered the 
first of the two classes of vegetable organs, 
viz. : such as tend to the support and growth 
of the plant, including roo^, sterfi, leaf, and a.p- 
pendages ; we shall next examine the class 
of organs whose chief use appears to be that 
of bringing forward the fruit. 
LECTURE XI. 
CALYX. 
We are now to consider the second division of vegetable organs, 
viz.: such as serve for the reproduction of the plant, called organs of 
fi:'uctification. Their names were considered when commencing the 
analysis of flowers ; but we are now to examine them with more 
minute attention, and to remark upon their different uses in the 
vegetable economy. 
You are no doubt pleased to have arrived at that part of the plant, 
which is the ornament of the vegetable kingdom. Flowers are de- 
Pubescence— Bract— Difference between the real leaf and the bract— Recapitulation 
-^second division of vegetable organs. 
6* ^ 
