330 
r April 29, 1886. 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
THE BEQUIREMENTS. 
What, then, is our machine—the root—called on to do ? In all cases to 
lay hold of the soil and secure the plant mechanically. How it does this 
will be sufficiently though incidentally illustrated later on, and it is not a 
subject on which we as cultivators need linger long. The plants we have 
now to deal with may ba lifted out of the ground by frost, but they are 
hardly likely to be washed away by floods or uprooted by winds. To pot 
firmly and press the crown firmly into the soil in transplanting are lessons 
which common experience teaches, lessons which the conformation of the 
root to be presently noted, do but accentuate. 
Another universal duty imposed on the root is to feed the plant. There 
is soil-food and there is air-food. The leaves, stimulated by light and heat, 
collect and transform the oue ; the roots, influenced by heat, absorb and 
digest the other. How they do these things is beyond the purpose of this 
paper to explain, but reference to any modern botanical text-book, and in 
particular to the truly marvellous revelations contained in the chapters on 
root movements in Darwin’s “The Power of Movement in Plants,” will 
supply the information and afford indications of the processes of absorption, 
of solution, of fermentation, of transformation, which, with or without the 
Fig. 57.—Germination oi P. reticula's. 
agency of minute Bacterian organisms, constitute each root-tip, each root- 
hair, a laboratory and a workshop. Each root-tip, each root-hair, moreover, 
is as sensitive as a nerve, not only responding to a touch, but transmitting 
impressions from the spot touched to adjoining cells. It is as mobile as a 
muscle, turning towards what is useful to it, bending away from what is 
noxious or obstructive, threading its way through the soil, and adapting 
itself to circumstances as if it really possessed intelligence. It acts like the 
brain, says Darwin; and truly as a sentient organ, receiving and trans¬ 
mitting impressions and directing the course of growth and movement, it 
would be hard to say wherein its inferiority to the nervous system of the 
lower animals consists. 
In the case of annual plants which live their life within the compass of 
a few weeks or months there is little else for the root to do than to secure 
the plant in the ground and to go in search of food and turn it to account 
when found. 
But in the case of perennial plants, such as most of onr Primulacese, 
another duty becomes incumbent—that of providing a store-place for water 
and for food. The food so stored, principally starch and allied substances, 
is not absorbed directly by the root and packed away, but partly by root- 
action and soil-food, partly by leaf-action and air-food, is manufactured in 
the leaves and afterwards transferred and deposited in the root or in the 
root-stock. 
A similar formation of starch takes place in annual plants, but it is used 
up in process of growth or stored in the seed to be turned to use by the 
seedling plant when it begins life on its own account. In any case the 
storage requirements of an annual are small in comparison with those of a 
perennial. To ascertain how and in what manner the food is obtained, 
transformed, stored, and employed is surely to put ourselves in possession 
of information, of any that could be named, the most important for cultural 
purposes. 
Another phase of work which it falls to the lot of the root (sensu latiori) 
to achieve is that of propagation, and by observing how this is effected 
spontaneously we may surely obtain some useful hints for our own artificial 
procedures. 
Such, then, in very general terms, is the nature of the work to be done ; 
such, in general outline, are the requirements of the case. 
THE MECHANISM. 
In the following remarks it is proposed to give a few illustrations of the 
machinery by means of which the work just alluded to is done, for while 
the work is in all cases the same, the machinery by which that work is 
accomplished is manifold in detail. 
point of view they might be passed over if it were not for one circumstance 
frequently ignored or overlooked, though one of great importance—the fact 
that seedling plants, even of those species destined to be perennial, are, to 
all practical intents, annuals. Barring the slender resources stored up in the 
seed, the seedling plants have little store to draw upon, and thus, like the 
annuals, they must have good food within easy reach, and be provided with 
rapid means of utilising it, else they wither away.* 
Centunculus minimus .—A weed no cultivator would bestow a thought 
upon, unbss it were to compass its destruction, may, nevertheless, serve 
as a useful illustration. It sends down into the soil a slender tap-root, 
which speedily ramifies just below the surface, branches and branches again 
till it, as it were, invades a considerable area of soil. There are no great 
Fig. 58.—Boot system of P. rosea. 
“ hold-fast roots—none are needed, but, on the other hand, there is a great 
multiplication of small fibres, and a consequent extension of absorbent sur¬ 
face. Notice, too, that there is no caulicle ; in other words, the radicle comes 
straight away from beneath the two cotyledons without there being any per¬ 
ceptible internode (stalk) between the base of the seed-leaves and the top of 
the root. In a seedling Primrose may generally be observed the radicle, 
giving off branches, then an erect cylindrical portion bearing the cotyledons or 
seed-leaves, but sometimes reduced to very small dimensions ; this is the 
caulicle or tigellum. Above the two seed-leaves is the plumule, consisting 
ANNUALS. 
Very few cultivated Primulace® come under this head. Some of the 
Androsaces and Anagallis are annuals but speaking from a cultivator’s 
“ Some [seed] fell upon stony places, where they had not much earth ; and forthwith 
they sprung up, because they had do deepness of earth : and when the sun wa3 up they 
were scorched : and because they had not root, they withered away.”— Matthew xiii., 5, 0. 
