THERE are some eight or ten species of zinnia known to gardens, but only one of them has become a favourite, and that abundantly deserves the pre-eminence it has attained as one of the most splendid of our annual flowers. The figure carries us back to the original form of the flower as it was known fifty years ago, and it represents very faithfully the variety known as "coccinea," or the scarlet-rayed zinnia. The species was introduced from Mexico in 1796, and the scarlet-rayed variety came into our hands in 1829, and was thought much of for its brilliant colour and stately habit. During the fifty years that have elapsed since it appeared, the flower has been improved in all its characters, and we now possess a race of perfectly double zinnias, the flowers of which show no central disc, but are perfect rosettes of exquisite form, and of every shade of colour except blue. There is not a more striking instance of floral advancement, accomplished by systematic selection, than is afforded by the zinnia, which is at once one of the largest, most various, and long-standing of our many good and cheap annual flowers.

The zinnia is named in honour of J. G. Zinn, Professor of Botany and Natural History at the University of Gottingen. He was born in 1826, and studied under Haller. One of the most important of his labours was a demonstration of the relation of vision to the action of the brain as well as to the structure of the eye, the particulars of which were given in his essay entitled "Description Anatomica Oculi Humani." Another important service rendered to science was his catalogue of the plants in the Academical Garden of Gottingen. He died in April, 1758, at the early age of thirty-two.

The zinnia belongs to the great family of composite flowers, and is a native of Mexico. It is sometimes called the Mexican marigold-a designation in some degree justified in the case of the yellow varieties, but by no means to be encouraged, for in its essential character it is some distance removed from the genus Tagetes, and its normal colour is red or crimson; and hence the finest varieties are certainly not, even by a stretch of fancy, to be classed with marigolds.

How to grow the zinnia is perhaps the question of principal importance to the readers of this. It is a half-hardy annual, and must not be grown in a half-hearted manner. The seeds should be sown about the middle of April, but not earlier. They may be sown on a hotbed, and they will then germinate very quickly. It is, however, better practice to sow in a frame or under a hand-light, in light rich earth, so as to obtain the plants by a slower method, and with a corresponding surety of a fine bloom. If the weather happens to be cold, cover the frame over at night with a mat, and give no air at all until the plants begin to appear, when air should be given cautiously, so as to prevent any shrivelling of the tender leaves by a dry east wind, and at the same time to ensure that healthy "stubbiness" that is so desirable in all young plants. As the plants advance they will require water and air increasingly, and nearly the same treatment as balsams demand should be given them. One point must be impressed on the mind of the amateur, and it is that, in common with the aster, the balsam, and other first-class annuals, the plants should never receive a check; for that will not only result in a deterioration of the bloom, but will also probably render the plant an easy prey to its myriad insect enemies.

The planting-out is an important matter. If the bed is made of old, sour, worn-out stuff, you will have no fine zinnias. The soil should be rather light and decidedly rich, and deeply stirred, and the position should be warm and sheltered. A garden in the northern suburbs of London, where the soil happens to be heavy and damp, was found to be unfavourable to zinnias, for the owner of that garden was resolved to have them as fine as he had often seen them in Paris, but had never seen them in England. And in the end this was accomplished, for a sloping bank facing the south was prepared for them, by deep digging, abundant manuring, and the incorporation with the stiff staple soil of a large proportion of road-grit and leaf-mould. Then, indeed, the zinnias displayed their beauties lavishly, and all the extra labour was amply compensated.

In any case, the bed should be made ready at the time the seed is sown, or earlier. As to the time for planting out, that must depend in part upon the weather, and in part on the state of the plants. Choose mild quiet weather if possible, but above all things have the plants stubby and strong, and of a healthy green colour, as the result of the access to them of abundant light and air. If you must plant during dry sunny weather, you have but to shade and water them carefully, and take care that the plants do not suffer any serious check.

There are two so-called species of zinnia that occasionally obtain attention--namely, the Z. grandiflora and Z. tenuifolia; but as ornamental plants they are of no particular value, and it does not appear to the writer hereof that they are ugly enough to please the botanist--the reader being of course aware that, by a bit of harmless irony, the florists hand over to the botanists all the ugly and unmanageable plants that they have resolved to exclude from their gardens. But of the veritable Zinnia elegans there are innumerable varieties, single and double, and all are good; but the crimsons and scarlets, of all amongst our annual flowers, are the best, the yellows and purples come next in merit, and the whites must rank lowest of all.