CHAPTER VII 
c 
PLANT ORGANS AND ORGANISMS 
An organ is a part of an organism made up of several tissues and 
capable of performing some special work. 
An organism is a living entity composed of different organs or 
parts with functions which are separate, but mutually dependent, 
and essential to the life of the individual. \j 
The organs of flowering plants are either Vegetative or Reproduc¬ 
tive. The vegetative organs of higher plants, are roots, stems, and 
leaves. They are concerned in the absorption and elaboration of 
food materials either for tissue-building or storage. 
The reproductive organs of higher plants include those structures 
whose function it is to continue the species, viz.: the flower, fruit and 
seed. 
The ripened seed is the product of reproductive processes, and the 
starting point in the life of all Spermatophytes. The living part of 
the seed is the embryo, which, when developed, consists of four parts, 
the caulicle, or rudimentary stem, the lower end of which is the be¬ 
ginning of the root, or radicle. At the upper extremity of the stem 
are one, two, or several thickened bodies, closely resembling leaves, 
known as cotyledons, and between these a small bud or plumule. 
The function of the cotyledon is to build up nourishment for the 
rudimentary plantlet until it develops true leaves of its own. r 
THE ROOT 
The root is that part of the plant that grows into or toward the 
soil, that never develops leaves, rather rarley produces buds, and 
whose growing apex is covered by a cap. 
The functions of a root are absorption, storage and support. Its 
principal function is the absorption of nutriment and to this end it 
generally has branches of rootlets covered with root-hairs which 
largely increase the absorbing surface. These root-hairs are of 
12 I 
