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Minor Convolvulus
Convolvulus minor.
CONVOLVULUS MINOR--the preferable name of this plant--is also known as C. tricolor, an appropriate but indefinite name. The prominent colours of the flower are blue upon the limb, yellow in the centre, with an intermediate ring of white. The average height of the plant is a foot to a foot and a half; the leaves are spatulate, fringed with hairs; the whole plant is downy, and of a full green colour.
This extremely beautiful plant is a hardy annual, which may be sown in autumn or spring. It requires a rich, mellow soil and an open situation to develop its characteristics fully; and, when liberally cultivated, it flowers for three months continuously, and a large mass of it presents a most refreshing and exquisite appearance in the early hours of the day. It may, in one sense, be regarded as a sunflower, and there is some utility in so regarding it, for if a bed on the south side of a house be planted with convolvulus minor, very few of the lovely flowers will ever be seen from the windows. But, on the other hand, a similar bed on the north side will display its flowers to the windows freely, for nine-tenths or more of the whole number produced will be found to face the south and the south-east.
The major convolvulus belongs to another section of the great family of convolvulaceae, of which there are four conspicuous genera in cultivation. The genus Calystegia includes our great white hedge bind-weed (Calystegia sepium) and the pink-flowered C. pubescens, of which there is a double variety in cultivation, the flowers of which, though poor, may be likened to roses. The genus Ipomoea comprises Ipomoea purpurea, the major convolvulus, and a number of resplendent species, some of which are hardy, but others require strong heat to start the seeds and green-house culture to produce the flowers. One of the most beautiful of this section is I. rubro-carulea, with large flowers of a brilliant sky-blue colour. It is a green-house perennial, native of Mexico. The genus Conrolvulus includes the subject of our plate; also C. scammonia, which produces the scammony of commerce, and the little wayside convolvulus, that makes a fairyland of many a mile of dusty English roadside and railway bank--this pretty pink-flowering species being known as C. arvensis. The genus Pharbitis consists for the most part of American annuals, some of which are usually classed under Ipomoea.
One of the most important members of this order is the Sweet Potato (Convolvulus batatas). This is largely cultivated in the tropics and the south of Europe for its edible roots, which are sometimes of a club shape, or that of an oblong and extremely ugly potato, of a reddish colour. When cooked they are excessively sweet, and scarcely attractive in appearance, and certainly need for their appreciation a palate trained to their liquorice flavour. When the potato of the present day was as yet unknown in this country, the sweet potato was regularly imported, and no doubt was very much enjoyed by the English people as a wholesome article of diet. Being usually of greater size and weight than the potatoes we are now accustomed to, there is a special reserve of fun in the exclamation of Falstaff, "Let the sky rain potatoes and hail kissing-comfits," "Merry Wives" (act v., sc. 5). The coarse red, fleshy root of the sweet potato is employed by Shake-speare in another place, to help out the description of "the devil luxury," "Troilus and Cressida" (act v., sc. 2).
These are not the only examples of useful species of convolvulus. The Mexican plant Ipomoea purga produces the jalap of commerce, and Convolvulus dissectus abounds in prussic acid, the liqueur known as Noyau being prepared from it, with the aid of alcohol. Finally, and omitting much that might be said if the subject were formally set before us, it may interest the reader to know that the oil of rhodium, which is said to be so attractive to rats as to cause them to swarm to it without fear, even if held in the hand of a ratcatcher, is the produce of a convolvulus known as Rhodorhiza.
It appears to be a long journey through the vegetable kingdom from our pretty and harmless Convolvulus minor to the extremely beautiful but pernicious British weed Dodder, Cuscuta epithymum. But to the botanist the transition is easy and natural, for the dodder, which by its parasitic growth of crimson stems strangles the plant it feeds on and so renders the ground barren, is a quite characteristic member of the great order Convolvulaceae, producing minute flowers of great beauty of a true convolvulus shape. A prominent characteristic of the order is the production of an imbricated calyx, two of the sepals being quite exterior to the other three. But a still more remarkable convolvulus is the East Indian plant called Neuropeltis racemosa, the flowers of which are produced in the centre of bracteal leaves, as though a flower should grow out of the palm of one's hand, or as tiny clusters of leaves occasionally appear in the very centre of large cabbage-leaves. In this the imbricated arrangement of the calyx is found to afford a trustworthy family likeness.