This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Annual or perennial, rarely somewhat shrubby herbs. Leaves alternate, with persistent often foliaceous stipules. Peduncles axillary, usually one-flowered. Many species produce dimorphous flowers. The Spring flowers are usually sterile, and the small apetalous Summer ones fertile. Sepals nearly equal, produced downwards below the point of insertion. Petals spreading, the lower often larger and spurred or saccate at the base. Anthers subsessile, the connective broad with a membranous terminal appendage, the two lower stamens often spurred. Capsule 3-valved, with 3 parietal placentas, opening with elasticity. Seeds numerous, albuminous; testa crustaceous, often shiny. A genus of about a hundred species, very widely distributed, the majority in the northern hemisphere. The name is the ancient Latin one for plants of this genus.
§ 1. Melanium. Upper petals erect Stipules large and leaf-like.
1. V. tricolor. - Heartsease or Pansy (fig. 42). Even in the wild state the forms of this species, as usually defined, are very numerous. The commoner ones are arvensis and tricolor proper; the former with yellow or white petals scarcely exceeding the sepals, and the latter with larger purple and yellow petals. Another form is lutea, by some botanists considered as specifically distinct. This has medium-sized flowers, normally yellow, with a few dark purple stripes. It is a native of the mountainous districts of Britain and the Continent, and will not succeed in dry hot situations. It is uncertain whether the Pansies of our gardens have sprung from this species alone, or whether V. altaica and V. Rothomagensis have been inter-crossed with it to produce them; but from the experiments of various horticulturists it would appear that the former is the more probable source of their origin. Indeed, some are inclined to consider these 'species' as races of V. tricolor. However that may be, there is no doubt of the wondrous diversity and beauty of the cultivated varieties, ranging in colour from white, yellow, lilac, violet, and purple in different tints to nearly black, and others in which there is some combination of these colours. There is no longer the same rage as formerly for the named varieties, though some of the self-coloured ones are now extensively employed for massing. Pansies have long been cultivated; but Lady Mary Tennet, about the year 1812, assisted by her gardener Richardson, was the first to devote attention to the selection of fine varieties.
Fig. 42. Viola tricolor, var. (1/3 nat. size.)
2. V. calcarata. - A dwarf free-blooming species with numerous underground creeping stems. Leaves crenate, ovate or oblong-lanceolate; stipules entire, 3-toothed, or pinnatifid. Spur as long as the petal, slender. Flowers large, pale blue. A variety called V. Zoysii has smaller yellow flowers. Switzerland.
3. V. cornuta. - Closely allied with the foregoing, but having broader less deeply crenate leaves, and of more erect growth. The stipules are not so deeply divided, and the flowers are of a darker blue. A native of the mountains of Europe.
There are several varieties in cultivation which are referred to this species, and valuable on account of their profusion of flowers.
§ 2. Nomimium. Upper petals projecting forwards. Stipules not leafy.
V. odorata. Sweet Violet. - This species is too well known to need description. It is the only one of this section in general cultivation. The varieties are numerous, double and single, violet, white, and mottled with the two colours, and some of them bloom nearly all the year round. The variety called the Czar is one of the best, producing its long-stalked large blue fragrant flowers in the greatest profusion during with a different colour from the white or yellow ground, sometimes with the limb spotted or marked with the same or a different colour. In England, it appears, little importance in classification is attached to the presence or absence of fringe at the extremity of the petals.
In France also Carnations are usually divided into three principal classes, which, however, are founded upon different characters. They are Grenadins, Flamands, and Fancies. The Grenadins are cultivated almost solely for the perfumes they afford. The flowers are of medium size, single or double, fringed, unicoloured, deep purple, violet, or verging upon chestnut brown, all exhaling a grateful odour. The Flamands (fig. 43) have large more or less double very round flowers, raised or convex in the centre, with the petals quite entire and unicoloured, or banded longitudinally with two or three distinctly defined colours or tints upon a white ground. The Fancies are subdivided into German and English, with the petals either toothed or not, but marked or striped with two or three different colours upon a yellow ground of various shades in the former, and wholly white in the latter. It will thus be seen that the English Picotees belong to the French Fancies, and the Flakes and Bizarres with entire petals to the Flamands.
A fourth class, called Proliferous Carnations, was formerly cultivated, but plants of this class are now usually discarded. They are so excessively double that the buds split up one side instead of opening regularly, thus giving the flower a very ragged and untidy appearance.
The Flamands are so numerous, and for the greater part so ephemeral, that it would be quite superfluous to enumerate them here. The merit of discovering the Perpetual Carnation is due to a French gardener, M. Dalmais, of Lyons, and since then many varieties possessing this unexpected duality have been raised by various horticulturists.
Fig. 43. Dianthus Caryophyllus, Bizarre variety. (1/2 nat. size.)