GERANIUM, the name of a genus of plants, the type of the family Geraniaceae. The name, as a scientific appellation, has a much more restricted application than when taken in its popular sense. Formerly the genus Geranium was almost conterminous with the order' Geraniaceae. Then as now the geranium was very popular as a garden plant, and the species included in the original genus became widely known under that name, which has clung to them ever since, in spite of scientific changes which have removed the larger number to the genus Pelargonium.
The species of Geranium consist mostly of annual or perennial herbs, dispersed throughout the temperate regions of the world. They number about 30o and bear a considerable family resem blance. The leaves are for the most part palmately-lobed, and the flowers are regular, consisting of five sepals, five imbricating petals, alternating with five glandules at their base, ten stamens and a beaked ovary. Fourteen species are natives of the British Isles and are popularly known as crane's-bill. G. Robertianum is herb-Robert, a common plant in hedgebanks. G. sanguineum, with flowers a deep rose colour, is often grown in borders, as are also the double-flowered varieties of G. pratense. Many others of exotic origin form handsome border plants in our gardens of hardy perennials.
In North America about 25 species of Geranium are found, in clusive of several naturalized from the Old World. Of the native species well-known representatives are the spotted crane's-bill or wild geranium (G. maculatum), common in woods from New foundland to Manitoba and southward to Georgia and Nebraska, with handsome rose-purple flowers, 1 in. to 12 in. broad; the Carolina crane's-bill (G. carolinianum), found in barren soil across the continent from Nova Scotia to British Columbia and south ward to Florida and Mexico, with pale pink or white flowers about in. broad; and the herb-Robert mentioned above, which is native to rocky woods from Nova Scotia to Manitoba and south ward to New Jersey and Missouri.
Pelargonium, though agreeing with Geranium in certain points of structure, differs in that the flowers are irregular, the two petals w',.:ch stand uppermost being different—larger, smaller or differ ently marked—from the other three, which latter are occasionally wanting. This irregularity the modern florist has done much to annul, for the increased size given to the flowers by high breeding has usually been accompanied by the enlargement of the smaller petals, so that a near approach to regularity has been in some cases attained. Another well-marked difference, however, remains : the back or dorsal sepal in Pelargonium has a hollow spur, which is adnate, i.e., joined for its whole length with the flower-stalk; while in Geranium there is no spur. This peculiarity is best seen by cutting through the flower-stalk just behind the flower, when in Pelargonium there will be seen the hollow tube of the spur.
The various races of pelargoniums have sprung from the inter mixture of some of the species obtained from the Cape of Good Hope. The older show-flowered varieties have been gradually acquired through a long series of years. The fancy varieties, as well as the French spotted varieties and the market type, have been evolved from them. The zonal or bedding race, on the other hand, has been more recently perfected; they are supposed to have arisen from hybrids between Pelargonium inquinans and P. zonale. In all the sections the varieties are of a highly orna mental character, but for general cultivation the market type is preferable for indoor purposes, while the zonals are effective either in the greenhouse or flower garden. Some of the Cape species are still in cultivation—the leaves of many being beauti fully subdivided, almost fern-like in character, and some of them are deliciously scented ; P. querci f olium is the oak-leaf geranium. The ivy-leaf geranium, derived from P. peltatum, has given rise to an important class of both double- and single-flowered forms adapted especially for pot culture, hanging baskets, window boxes and the greenhouse.
The best soil for pelargoniums is a mellow fibrous loam with good well-rotted stable manure or leaf-mould in about the pro portion of one-fifth; when used it should not be sifted, but pulled to pieces by the hand, and as much sand should be added as will allow the water to pass freely through it. All are readily increased by cuttings made from the shoots when the plants are headed down after flowering, or in the spring, when they will root freely in a temperature of 65° to 7o° F. They must not be kept too close, and must be very moderately watered.