Encyclopædia Britannica, Ninth Edition/Strawberry
STRAWBERRY (Fragaria). Apart from its interest as a dessert fruit (see Horticulture, vol. xii. p. 276), the strawberry has claims to attention by reason of the peculiarities of its structure and the excellent illustrations it offers of the inherent power of variation possessed by the plant and of the success of the gardener in availing himself of this tendency. The genus Fragaria consists of a small number (three to four, according to Hooker) of species, native of the temperate regions of both hemispheres, as well as of mountain districts in warmer climes. The tufted character of the plant, and its habit of sending out long slender branches (runners) which produce a new bud at the extremity, are well known. The leaves are usually palmately three-parted, but the number of leaflets may be increased to five or reduced to one. While the flower has the typical Rosaceous structure, the so-called fruit is very peculiar, but it may be understood by the contrast it presents with the “hip” of the rose. In the last-named plant the top of the flower-stalk expands as it grows into a vase-shaped cavity, the “hip,” within which are concealed the true fruits or seed-vessels. In the rose the extremity of the floral axis is concave and bears the carpels in its interior. In the strawberry the floral axis, instead of becoming concave, swells out into a fleshy, dome-shaped or flattened mass in which the carpels or true fruits, commonly called pips or seeds, are more or less imbedded but never wholly concealed. A ripe strawberry in fact may be aptly compared to the “fruit” of a rose turned inside out.
The common wild strawberry of Great Britain, which indeed is found throughout Europe and great part of North America, is F. vesca, and this was the first species brought under cultivation in the early part of the 17th century. Later on other species were introduced, such as F. elatior, a European species, the parent stock of the hautbois strawberries, and especially F. virginiana from the United States and F. chiloensis from Chiloe. From these species, crossed and recrossed in various manners, have sprung the vast number of different varieties now enumerated in catalogues, whose characteristics are so inextricably blended that the attempt to trace their exact parentage or to follow out their lineage has become impossible. It must suffice to say that the varieties at present cultivated vary in the most remarkable degree in size, colour, flavour, shape, degree of fertility, season of ripening, liability to disease, and constitution of plant. Some, as previously stated, vary in foliage, others produce no runners, and some vary materially in the relative development of their sexual organs, for, while in most cases the flowers are in appearance hermaphrodite, at least in structure, there is a very general tendency towards a separation of the sexes, so that the flowers are males or females only as to function, even although they may be perfect in construction. This tendency to diœcism is a common characteristic among Rosaceæ, and sometimes proves a source of disappointment to the cultivator, who finds his plants barren where he had hoped to gather a crop. This happens in the United States more frequently than in Britain, but when recognized can readily be obviated by planting male varieties in the vicinity of the barren kinds. Darwin, in alluding to the vast amount of variability in the so-called “fruit,” a change effected by the art of the horticulturist in less than three centuries, contrasts with this variability the fixity and permanence of character presented by the true fruits, or pips, which are distributed over the surface of the swollen axis. The will and art of the gardener have been directed to the improvement of the one organ, while he has devoted no attention to the other, which consequently remains in the same condition as in the wild plant. Too much stress is not, however, to be laid on this point, for it must be remembered that the foliage, which is not specially an object of the gardener's “selection,” nevertheless varies considerably.