548. The plants grown in the open air in villa gardens may be divided into the ligneous, including the trees and shrubs; and the herbaceous, including the annuals, the biennials and perennials, and the bulbs and tubers. The herbaceous plants being those most generally cultivated in villa gardens, we shall give them most in detail, referring to the lists of ornamental trees and shrubs already given in many of the preceding pages of this work, but more particularly in pages 68, 99, 100, 101, 147, 148, 262, 263, 291 to 293, 330 to 338; and from these lists selections may easily be made. The culture of trees and shrubs will be found by reference to the Index, in various places throughout the work.

Section I. Herbaceous Plants

549. The term "herbaceous plants," is generally applied by gardeners only to perennials; but, in fact, it belongs to all plants the stems of which are not woody, but are composed principally of what is called cellular tissue., Plants of this kind are subdivided into those with fibrous roots, and those with bulbous or tuberous roots; though the latter are, properly speaking, underground stems, with fibrous roots attached. The fibrous-rooted plants are again divided into annuals, biennials, and perennials; and under these heads we shall consider them.

Subsect. I. Ornamental Annuals

550. Annual plants are, properly speaking, plants which only live one year; but gardeners generally include under the term all that flower the same year that they are sown. Many of the plants of warm climates will do this in England, and die in winter, being killed by the first frost, which will live many years in their native climes, or even when they have the protection of a green-house in England. Thus, for example, the common mignonette, which is always considered as an annual in England, is a shrub in its native country, Barbary; and it may be trained into the appearance of a small tree in this country, by keeping it in a green-house and pinching off the lower side shoots as they appear. Besides the common annuals, which are sown in April or May, there are what are called the Californian annuals, which are sown in autumn, as soon as the seeds are ripe, and which flower in very early spring. There are also the half hardy annuals, which are sown in a frame on a hotbed; and there are tender annuals, which are raised on a hotbed, and flowered in the green-house or the stove.

551. The culture of annuals embraces their sowing, their thinning or transplanting, and their training; and these operations are nearly the same whether the plants are hardy, half hardy, or tender; the only difference being, that the hardy plants will grow freely if sown in the open air where they are intended to remain, while the half hardy kinds must be raised on a hotbed, and transplanted into the open ground in May or June; and the tender kinds must be kept in pots, and only placed in the open air during the warmest part of summer.

552. When the seeds of annuals are sown, the ground should first be made firm by pressing it with the saucer of a flower-pot, or the back of the spade; the seeds should then be sprinkled thinly oyer the ground, and just covered with fine earth, which should be slightly pressed down over them. When they come up, if they appear too thick, they should be thinned out so as to leave each plant standing apart; the distance at which they are left from each other varying, of course, according to the strength and habit of growth of the plants. The plants of some kinds of annuals will bear transplanting after they have been taken up in thinning, but generally they are not worth the trouble of replanting. The seeds when sown are often destroyed by birds; but this may be prevented by turning a flower-pot over each patch till the seeds have germinated, taking care; however, to remove it as soon as the plants begin to grow, lest they should be drawn up by the shelter thus afforded, and become weak. Snails and slugs are dangerous enemies to young and tender annuals, and care should be taken to search for them early in the morning and late in the evening; or to destroy them by watering the ground with lime-water, so weak as not to disfigure the plants. - (Ladies' Companion to the Flower-garden,)

553. List of ornamental annuals which should be sown in the open ground towards the end of March or the beginning of April: