Lex. OUTLINES OF BOTANY. 
§ 4. Functions of the Organs. 
. The functions of the root are: —1. To fix the plant in or to the 
cil 0 other substance on which it grows. 2. To absorb nourishment 
he s 
tem is th s) 
nutriment absorbed consists chiefly of carbonic acid and nitrogen or 
nitrogenous compounds dissolved in water. 3. In some cases roots secrete 
or exude small quantities of matter in a manner and with a purpose not 
satisfactorily ascertai 
217. The Stem gat its os ora support the leaves, flowers, and fruit, 
transmit the crude sap, or ae absorbed by the roots ‘and m ixed 
with previously organized eee, the leaves, org re-transmit the 
assimilated or elaborated sap from ps ee res to the wing parts of 
the plant, to be there used up, or to form deposits for future use (204), 
a ‘ 
8 on of th g ecru 
through the elongated cells associated with the v scular eo any passing 
from one cell to another by a process but little whideweand: but kn nown 
ssi name of endosmose. 
Leaves are functionally the most active of the organs of vegetation. 
* pete is chiefiy con nducted digestion or Assimilation, a name given to 
t ich accomp : i 
; of the 
residue of the crude sap into the secteoers ‘substances which enter into 
the composition of the plant. The exhalation of oxygen appears to take 
place under the influence of solar heat aa ‘Tight, chiefly from the nate er 
lw 
sO in certain cases. The transformation of the sap is effected within 
the tissues of hg leaf, and c ee probably more or less throughout 
219. The floral organs seldom pani ibute to the growth of the plant on 
which they are produced; their functions are wholly  peonizeied on the 
formation of the og with the germ of a future plan 
20. The perianth (calyx and corolla) acts in the ah instance in pro- 
tecting the See and pistils during the early stages of their development. 
en goomeegs e use of the brilliant per 7 t which a one a 
of the sweet or stro rong odours they emit, has no adequately 
explained. theless they may have great influence in attracting thos 
insects whose concurrence has been sho own in many cases to be necessary 
ce 
for the aie transmission of the pollen from the anther to the aes 
221. The pistil, when stimulated by the action of the pollen, forms and 
ung hy 
seed. 
which the pollen is conveyed to the stigma, whether by elastic action of 
the organs themsely ves, or with the assistance of wind, of insects, or other 
