332 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ April 19, 1886 
matter?, but we may perchance profit somewhat if we make use of it as an 
illustration of general application. 
THE ROOT-STOCK. 
The body which emits roots on the one side or beneath, and throws up 
leaves and flowers on the other is the “ rhizome,” or root-stock. It is usually 
subteiranean, and so gets called a root, but inasmuch as it produces leaves, 
buds, and offsets, and has the internal structure of a stem, botanists will not 
admit its claim to be considered a root, for a root, under ordinary circum¬ 
stances (exceptis prmtermissis), does none of these things. It is a develop¬ 
ment of the plumule or of the caulicle, or of both together. Usually it is 
more or less horizontal in its direction, as in the Primrose, in other cases it 
is vertical, as in the Auricula, where it thrusts itself above ground, and gives 
off buds or offsets in such a way that no one can mistake it for a root. Hori¬ 
zontal or erect, it throws down feeding-roots into the soil, and these roots are 
usually fleshy, serving, indeed, not only as feeders, but as storeplaces as 
well, thus sharing the office of the stock itself. At the free end of the stock 
is a bud, or a cluster of buds, by means of which the plant grows (figs. GO, 
Gl, G2). From these buds upspring the leaves and the flowers. 
POLARITY OP THE STOCK. 
Owing to this position of the buds the stock grows at one end, and extends 
and pushes itself into new territory, while the other end of the stock, having 
yielded up its store of water and starch to the growing bud, gradually 
decays. Thus the plant effects very quietly and gradually a change of 
residence an indication of the desirability of occasional transplantation. 
This progressive decay at one end suggested to old Auricula growers the 
removal of the end of the Carrot,” and there was nothing to be said against 
the process provided their surgery was confined to dead portions only, and 
did not include the healthy and (potentially) active roots also. In such a 
case the stock is put to the trouble of making new roots, which, to say the 
truth, it does not fail to do speedily under propitious circumstances. 
The progressive growth at one end associated with progressive decay at 
the other, is a very marked feature in Primulaceae. Moreover, it is often 
manifested in the earliest period. The root apparatus of the seedling plant 
seems destined for the use of the seedling only (which is thus, as before 
noticed, practically an annual), and when the plumule developes gradually 
into a permanent stem with its leaves and potential flowers, new roots are 
thrust out from the plumule, as may be seen in the illustrations of Primula 
r.ticulata, P. elatior (Sgs. 57, 59), and in P. verticillata. 
The development of the tufted stem from the plumule is well exemplified 
in the case of the Cowslip, as pointed out to me some years since by Mr. 
Holland The seedling plant germinates in the usual way, but after a time 
the weight of the rapidly growing plumule causes the caulicle to bend 
downwards and become more or less horizontal. Adventitious roots are 
then thrown out from the top of the original caulicle or the base of the 
plumule, which gradually decays, leaving the young plant independent. 
(Henfrey s Elementary Course of Botany,” ed. 4, p. G54.) 
PROTECTION. 
One other provision with reference to root-stock may here be noted, and 
that is the manner in which in most species, notably in P. latifolia, 
Pig. 62.—Auricula. 
P. graveclens, P. Palinuri, the deeply descending rhizome is protected from 
Joss of heat, as also from mechanical injury, by the dense covering afforded 
by the remains of the old leaves. Contrast this state of things with the 
way in which Auriculas thrust themselves out of the ground, their root- 
stalks showing little or no trace of the leaves beyond the scar, which 
indicates the p’ace whence they have fallen. It would be interesting to 
Jniw- m '^ let ^ er these jpeculiarities in the Auricula may not be connected 
(figs. of off sets (buds) from the side of the rhizome 
TUBERS. 
The tuber of a Cyclamen (a development originally from the tigellum) 
is essentially the same as the root-stock, differing only in its more or less 
globular form. It throws off feeding roots from its base or its sides, and it 
forms a bud or buds at the top. Its fleshy tissue is laden with starch and 
building material for new growth. 
In Trientahs, from the caulicle or from the base of the plumule emerge 
long subterranean branches, which end in thickened tubers like those of 
Convolvulus sepium. 
WINTER BUDS. 
In Primula rosea and P. involucrata, P. farinosa, P. rotundifolia (her¬ 
barium spec.), and probably in many other species, we find what may be 
termed winter buds. In point of fact, the stock in these cases decays away 
almost entirely, leaving only the buds which form at its extremity or at the 
ends of its branches. These buds are made of dilated leafstalks densely 
packed one over the other, like the similar parts in a “ head of Celery.” 
They are furnished at the base with numerous root fibres, very fleshy in 
P. involucrata fibrous in P. rosea (fig. 58), and which serve to supply 
sufficient moisture in the dry season. Carefully stowed away in the 
centre of the leaves is the inflorescence, whose tiny pearl-like flowers may 
be seen securely nestling, even in midwinter, beneath their protective wraps 
exactly as in the case of bulbs, or Cabbages in which the leaves “ turn in ” 
well. P. denticulata is not so fortunate. In this plant the leaves spread 
widely and do not close up to cover the inflorescence, the consequence of 
which is the latter is apt to be stimulated by the capricious and unseason¬ 
able gleams of sun that we get in some winters, and bursts into bloom at a 
time when “ a frost, a killing frost,” is only too likely to damage the blos¬ 
soms, or, if this does not happen, the flowers are liable to be rotted with 
wet or snow. Of cmrse this is easily prevented by laying a Fir branch or 
other protection over the plant. 
The formation of a thick root-stock of tubers, of fleshy roots, or of large 
winter buds, may all be taken as indicative that the plant is thrifty enough 
to lay by a provision for the future, and, moreover, that it adapts itself to 
falling temperature and other untoward circumstances, and goes to rest. 
To afford such rest in our uncertain climate is, as all gardeners know, occa¬ 
sionally a difficult matter. In my own experience, which, if personally 
small, is vicariously large, I find much virtue in a covering of Fern, straw, 
or a Fir branch. 
The foregoing remarks apply to plants growing m the open air or with 
no other protection than a cold frame in winter. Under glass the require¬ 
ments are somewhat different, and the conditions likewise. The plant is 
grown for some special purpose, and the gardener considers not so much 
the natural “ habit ” of the plant under normal circumstances and the way 
in which he may promote its welfare, as the manner in which he can induce 
it to adapt itself to his requirements and the conditions he offers. He may 
even find it requisite or advantageous to invert the natural course of things 
—to force when the plant, left to itself, would go to rest, to check growth 
when the natural tendency would be to progress. For instance, the forma¬ 
tion of the Cyclamen tuber is an indication that the plant under natural 
circumstances has a season of rest; and before Cyclamen culture had 
reached such a pitch of perfection as it has now attained growers were wont 
to give the tubers an enforced rest by drying them off. Now that practice is 
quite reversed ; and that such an amount of rest as the old growers gave the 
plant is not necessary under artificial conditions is shown by the fact that 
the foliage of the Cyclamen is persistent, and no deficiency of food to 
sustain this prolonged season of growth is to be feared, for food the 
gardener can give freely and at times when Nature herself might close her 
stores. This justifies the treatment of the Cyclamen as if it were a bulb 
with evergreen foliage. 
Servile imitation of Nature—such imitation, that is, as we can compass ! 
—is, to say the leist, not very much better than mechanical routine. The 
wisdom of the gardener is shown first in his knowledge of plants, and next 
in the skill and judgment which he brings to bear in inducing or helping 
the plant to adapt itself to unnatural conditions, and to the fulfilment of 
artificial requirements. 
Whether from the point of view of the physiologist or from that of the 
cultivator, a thorough study of the life-history of plants is absolutely 
essential to complete success. It is not given to any to reach the highest 
standard, but it is a satisfaction to know that every step in the way is a 
real gain—a link in the chain of true progress—a progress which, at least 
as far as the community at large is concerned, knows no countermarch. 
A STNOrSIS OF THE EUROPEAN SPECIES OF PRIMULA, 
WITH THEIR DISTRIBUTION. 
[A paper prepared lor the Primula Conference by Mr. J. G. Baker.] 
Group I. Primulastra. —Young leaves revolute, never mealy beneath. 
Calyx strongly ribbed. Flowers yellow. 
1, P. vulgaris, Huds. (Primrose).—Leaves narrowed gradually to the 
base. Umbel sessile ; pedicels long. Calyx-teeth lanceolate. Corolla-limb 
large, pale yellow.—Distrib.: Throughout Europe, except the Mediterranean 
region. 
2, P. elatior, Jacq. (true Oxlip).—Leaves narrowed gradually to the 
base. Peduncles produced ; pedicels short. Calyx-teeth lanceolate. Corolla- 
limb large, pale yellow; throat not plicate.—Distrib.: Throughout Europe, 
except the Mediterranean region. Differs from the hybrid Oxlip by its 
more villose calyx and paler corolla, not plicate at the throat. 
3, P. officinalis, Scop. (Cowslip).—Leaves narrowed suddenly at the 
base to a winged petiole. Peduncles produced; pedicels short. Calyx- 
teeth deltoid. Corolla-limb smaller, deeper yellow; throat plicate.— 
Distrib.: Throughout Europe ; rare and not typical in the Mediterranean 
region. 
Group II. Aleuritia. —Leaves often mealy beneath, revolute when young 
Calyx not ribbed. Flowers lilac. 
4, P. farinosa, Linn. —Leaves small, crenulate, mealy below. Pedicels 
and calyx also mealy. Caly-tube campanulate; teeth as long as tube. 
Corolla-tube short.—Distrib.; Northern and Central Europe, mountains of 
Spain 
