32 
CLASSIFICATION OF ORGANS 
distant ancestry. Almost all show distinction into root and 
shoot ; the reproductive function accompanies the latter, the 
former absorbs water from the soil. The shoot is nearly 
always divided into a reproductive part or inflorescence , and 
a non-reproductive part performing vegetative duties (see 
below). It is also usually divided into stem and leaf in 
both parts. It is convenient and fairly accurate, therefore, 
to divide the organs of plants into reproductive , concerned 
with the life of the race (inflorescence, flower, fruit, seed), 
and vegetative , concerned with the life of the individual 
(root, stem, foliage-leaf). Hard and fast lines cannot be 
drawn. Vegetative reproduction (see below) is common, 
and in many ferns &c. the reproductive and vegetative 
functions are performed by the same leaves. 
Vegetative Organs. 
The distinctions between root, stem, and leaf are not 
always easy to draw (cf. Anthurium, Neottia, Podostemaceae, 
Utricularia). The two last may best be considered together 
under the common term shoot, the distinction between which 
and the root is usually clearly marked even in the embryo. 
The root usually grows downwards into the substratum for 
the purposes of absorbing food substances and of anchoring 
the plant ; does not bear leaves nor the true reproductive 
organs, is endogenously branched, and usually bears a root- 
cap (see below). The shoot on the other hand (or part of 
it) usually grows above ground and consists in part of green 
tissue performing assimilatory functions ; it often bears leaves, 
and always the true reproductive organs, is exogenously 
branched, and has no cap. We shall first deal briefly with 
the vegetative functions, and then with the organs and their 
structure. 
Nutrition, Transpiration, Respiration, Meta- 
bolism. Most plants have green shoots or leaves, and in 
them the processes of nutrition are in general those described 
below ; the peculiarities of parasites &c. are described in 
Chap. III. 
Nearly all higher plants have roots or analogous organs in 
the soil (cf. water-plants, epiphytes, parasites, in Chap. III.). 
The water in the soil is held by capillary attraction, and 
