They differ in another respect from other bulbous plants described in this book, and that is in having "scaly" bulbs as shown on [page 12]. All the other plants have either bulbs with several coats rolled round each other (tunicated), or else they are solid, when they are known as corms. But in the Lilies neither of these two types appears. What are known as the "scales" are fleshy leaves that have been specially modified under the surface of the soil to act as reservoirs or storehouses for the surplus food that the green aërial leaves on the stems have elaborated for them during the daytime.
There are a large number of species of Lilium, differing greatly in size and blossom, and it is therefore only natural to expect the bulbs to vary a good deal also. Indeed, there are very large and very small bulbs, comparatively speaking, and they display a good deal of difference in their vegetation, and in producing offsets. For example, most kinds develop new bulbs or offsets round the base of the older bulb, while others, like canadense, Grayi, pardalinum, Parryi, and superbum, develop their new bulbs along creeping stems or rhizomes as shown in the sketch on [page 31].
Useful as the offsets are for the purpose of increasing the stock, some kinds, notably bulbiferum, Browni, speciosum, and tigrinum, often develop what are called "bulbils" in the axils of the aërial leaves. These bulbils are small bulb-like bodies, which, when sown and covered with soil as if they were large seeds, will develop into flowering bulbs in the course of two or three years. The origin of these bulbils is more fully dealt with at [p. 32].
Besides these two fairly easy means of increasing the stock of Lilies, many kinds may be also raised from seeds, which at the end of three, six, or eight years, will have produced bulbs large enough to throw up flowering stems. Raising Lilies from seed is more common now than it used to be, especially in America, where some lovely hybrids have been raised, such as Burbanki, Dalhansoni, Marhan, &c.
[Distribution of Lilies.]—As Liliums are distributed throughout all parts of the north temperate hemisphere—extending from California in the west, to China and Japan in the east, across the continents of North America, Europe, and Asia—they are therefore found naturally growing in different soils, and under various climatic conditions, in all degrees of sunshine and shadow, drought and moisture. In the British flower garden they are, as a rule, best in positions where they will be shaded from the hot mid-day sun, as the flowers will last much longer than if exposed too much. They should not, however, be planted in deep shade under trees, or among their roots, as the latter would absorb too much food and moisture from the Lilies, while the overhanging boughs would prevent the rain from reaching the bulbs in sufficient quantity. During vigorous growth, Lilies like plenty of water, but the soil must at the same time be so well drained that it shall readily pass away from the bulbs. ("A Practical Guide to Garden Plants.")
[Time and Depth of Planting.]—If bulbs can be secured early in autumn, say in September or October, that would be the best time to plant Lilies. But very often bulbs of certain kinds cannot be secured till spring, so that planting must necessarily take place then. The depth at which Lily bulbs are to be planted depends greatly upon the size of the individual bulbs; some kinds are planted about 6 inches deep, while others require a depth of 9 or 10 inches. A safe general rule to follow, is to cover the bulbs with about twice their own depth of soil when planting in the open air. If a piece of peat be placed beneath each bulb at the time of planting, and a layer of sand about half-an-inch thick round them, they will root much more freely. An exception to the general rule seems to be L. giganteum (see [p. 100]). When Liliums are hardy enough to be left undisturbed for several seasons in the same place, a good top-dressing or "mulching" of well-decayed manure in autumn will be of great advantage in replenishing the food for the roots.
So far as culture is concerned, Liliums may be arranged in three distinct groups as follows:—
I. Lilies that flourish in ordinary good garden soil, or better still, in strong loam that has been deeply dug and enriched with well-decayed manure in advance.
[Alexandræ], 2 to 3 feet high, with pure white flowers, 6 to 8 inches across in July and August.
[Batemanniæ], 3 to 5 feet high, flowers rich apricot, 4 to 5 inches across.