flowers flower species
VIOLET. The violets comprise a genus of at least one hundred, some say two hundred species, found principally in temperate regions of the northern hemisphere ; a few also occur in mountainous districts of South America, while the genus is not wholly without representatives in Australia. The species are mostly low-growing herbs with alternate leaves provided with large leafy stipules. The flowers are solitary, or rarely in pairs, at the end of slender axillary flower stalks. The flowers themselves are very irregular in form, with five sepals prolonged at the base, and five petals, the lowest one larger than the others and provided with a spur. The five anthers are remarkable for the petal-like processes which extend beyond the anther cells and form a sort of cone around the style. The ovary is superior, one-celled, with three parietal placentas and numerous ovules. It is surmounted by a single style, which terminates in a dilated or hook-like u The fruit is a capsule bursting loculicidally, i.e., through the centre of each of the three valves. The irregular con' struction of the flower is evidently connected with fertilization by insect agency. To reach the honey in the spur of the flower (of the pansy), says Muller, the insect must thrust its proboscis into the flower close under the globular head of the stigma. This lies in the anterior part of a groove fringed with hairs on the inferior petal. The anthers shed their pollen into this groove, either of themselves or when the pistil is shaken by the insertion of the bee's proboscis. The proboscis, passing down this groove to the spur, becomes dusted with pollen ; as it is drawn back, it presses up the lip-like valve (of the stigma) so that no pollen can enter the stigmatic chamber ; but as it enters the next flower it leaves some pollen on the upper surface of the valve, and thus cross-fertilization is effected. It is curious, however, that in the common violet, F. odorata and other species " cleistogamic " flowers occur of a greenish colour, so that they offer no attractions to insect visiters and their form is correspondingly regular. In such flowers self-fertilization is compulsory and very effectual, as seeds in profusion are produced.
Several species of Viola are native to Great Paitain. V odorata is highly prized for its fragrance, and in cultivation numerous varieties have originated. The garden pansies or lwartseases are derivatives from V. tricolor, a cornfield weed, V. altaira, and V. grandiflora. They are reputed to have been first raised about 1810 by Lady Mary Bennet, with the assistance of her gardener, Mr Richardson, the term Innsy or p,:nst'e having been long attributed to V. tricolor. The variety and richness of colouring in these flowers are very remarkal de. "Bedding violas," which differ from pansies in some slight technical details, have been raised by crossing lutes with V. calearata. The violas are credited with powerful emetic. and diuretic; properties, on which account they have been admitted into some of the pluumacopceias ; but they are now very little used.