THE POLITY OF A PRIMROSE.

FEW

EW subjects, if any, are better calculated to awaken a lively interest in the investigation of natural laws and the phenomena. of life at large, than the study of those processes of development whereby the races of animals and plants retain their hold upon the world, and maintain a continuous and unbroken round and cycle of existence. In such studies, more than in any others, we seem to gain near glimpses of Nature's ways and methods in fashioning the varied universe of living beings; whilst the lessors such topics are well calculated to enforce respecting the order of nature as a whole, form not the least important result of these investigations. The study of even the most commonplace object may, under the newer phases of research, be made to yield an amount of "sweetness and light" for which we might be wholly unprepared. The day of the Peter Bells, and of uninquiring moods and tenses, if not altogether a thing of the past, is happily already in its twilight stage. The schoolboy, with a primer of botany in hand, understands things at which the previous generation simply wondered. And even if the results of botanical study may occasionally be expressed by the hackneyed Wordsworthian phrase of "thoughts beyond tears," the modern student of plant-life has ample reason to congratulate himself on having attained the mastery of many ideas, which in past years were included under the poetic category of "expressive silence." The primrose still grows by the "river's brim," in truth, but it is no longer merely a yellow primOn the contrary, the flower is in greater part understood, the mechanism of its life is well-nigh completely within our mental grasp; and, best of all, its study has led in the past, as it leads even now, to the comprehension of wider ideas of nature, and more extensive views of plant life, than those which formerly met the gaze of the wayfarer in scientific pastures. The appreciation of what is involved in part of the life-history of a primrose may thus serve as a startingpoint for more extensive research into the phenomena of plantfertilisation at large; and this latter topic, in its turn, falls naturally into its proper niche in teaching us plain lessons respecting the manner in which the wide domain of life is regulated and governed.

rose.

By the "fertilisation" of a plant is meant to be indicated those actions or processes in virtue of which those little bodies or "ovules" developed in the seed-vessel (Fig. 1, 2) become "seeds,"

and through which they are fitted to develop into new plants. The unfertilised ovule is incapable of producing a new plant.

When set in the ground it would simply decay as if it were a leat or other detached and dead portion of the plant-economy. When, on the contrary, it is duly fertilised, the ovule, becoming the "seed," has become possessed of the powers and properties in virtue of which it is capable of evolving the form of the parent-plant from which it was derived. So much for the very necessary botanical distinction between "ovule" and "seed." The process of fertilisation is thus seen to be that on which the continuance of plant-existence depends. More closely regarded, it is known to be that which is capable under certain conditions of giving origin to new races or varieties of the plant-species. When the horticulturist, taking the pollen from one species or variety of plant, applies this fertilising matter to the ovules

of another variety or species, the characters of the two different races are combined and united in the "hybrid" progeny. Our gardens and conservatories—and, as we shall strive to show hereafter, the natural plant-creation at large-have benefited immensely in beauty from a knowledge of the changes in colour, form, and size, which this "cross-fertilisation" may produce. For instance, the finest ot our rhododendrons are crosses in which the characters of Indian and American species have been thus blended. The union of the common heartsease with a large-flowered foreign pansy, has produced a new stock in which the excellencies of both species are found. The pelargoniums of our conservatories represent hybrid stocks and varieties, which cross-fertilisation and cultivation have together produced from the small-petaled species of South Africa. Such results, among countless others, would seem to suggest that beneath the subject of cross-fertilisation, or even underlying that of ordinary fertilisation, there lies hid a mine of knowledge respecting the causes which have wrought out the existing variety of plant-life. And for the plain and unfettered understanding of the subject in its less technical phases, or to fix the foundations of knowledge respecting an interesting field of natural-history study, no better subject could be selected than the history of even the commonest flower-such as a primrose. Rightly

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A

B

FIG. 2. PRIMROSES.

comprehending what is included in the phases of primrose-life, we may hope successfully to read some of the more abstruse problems presented by the wider aspects of plant existence at large. "The ruthe primrose that forsaken dies," and the "cowslips wan that hang the pensive head," afford us delight even when we are living in all the It is not too much to say that

simplicity of botanical ignorance. their systematic study may lead to the higher delights and more cultured joys included in the knowledge of some phases of natural law and in an understanding of the hows and whys of living nature.

The elementary botany of a primrose is a matter of few words. Like every other perfect flower, it consists of four parts or circles of organs placed one within the other. Outside, we perceive the circle of fine green leaves, which we name the calyx, each green leaf of this organ being named a sepal. In the primrose, the sepals are united, although in many other flowers, (e.g., buttercup and wall-flower) (Fig. 1, ca), we should find them free and separate. The calyx of all flowers is, for the

most part, coloured green, its obvious use being to form a protective envelope for the other organs of the flower. Within the calyx, we descry the corolla (Fig. 2, co). This is the circle of petals or leaves which, par excellence,

we call the "flower," because it constitutes

in the vast majority of s flowers the bright and

S

B

NETTLE-FLOWERS.

be perfect enough minus its corolla; although the eye, missing the bright petals, would be apt to regard such a plant as wanting the first and chiefest element of the blossom. The common nettle, for instance, appears to possess no "flowers" in the popular and accustomed sense of the term; but when we examine the plant, we readily discover that it possesses parts corresponding to the flowers (Fig. 3) of other plants. In the greater nettle, the flowers of one plant are essentially different (in that they possess "stamens" alone)

FIG. 4 (A). FEMALE OR PISTILLATE
FLOWERS OF WILLOW.

FIG 4 (B). MALE OR STAMINATE
FLOWERS OF WILLOW.

from those of another plant (which possess "pistils" only). But in the lesser nettle, or in the oak (Fig. 5, A, B), these distinct flowers are found on one and the same plant. No vestige of colour appears in either, however; and when we study the flowers in question, we find that a corolla is wanting, although a calyx is present. Again, in the willow, which, like the greater nettle, has its stamens and pistils

(Fig. 4, A, B) on different plants, there appears to be no

flower" in

the ordinary sense of the term; and the calyx as well as the corolla is found to be wanting in these trees.

yellow dust termed pollen, which, at the time of ripening, is usually found scattered conspicuously about the interior of most flowers. The fourth and central set of organs found in the flower constitute

the pistil (Fig. 9) or seed-producing structure. This organ is composed of one or more parts called carpels. Each carpel consists in turn of a lower distended part called the ovary (Fig 9, ov), within which the ovules are produced; of a neck or filament, the style (st); and of a head borne on style (sg), and named the stigma. The style or stigma may be absent, but in the great majority of flowers both parts FIG. 5 (B). PISTILLATE FLOWERS OF OAK. are present, the ovary being, however, the essential part of the pistil. In the "head" of a poppy, for instance, there is no style; the bulk of the "head" consisting of the ovary, containing its numerous seeds, and the flat cap or lid re pre