There is so much confusion of thought as to what a "bulbous" plant really is, that it may be as well at the beginning of this volume to endeavour to clear up the haziness that exists in regard to the matter. It seems to be taken for granted that any plant with a swollen or thickened stem or rootstock is a "bulbous" one. And this impression is no doubt confirmed when one consults the bulb catalogues issued by nurserymen. In these publications—chiefly, no doubt, for the sake of convenience and to avoid unnecessary extra expense in printing—a large number of plants are enumerated as if they were really bulbous. It is, therefore, not at all unnatural that the amateur should come to the conclusion that everything mentioned between the covers of a bulb catalogue should be truly bulbous in nature. Even some publications on bulbous plants have adopted the same loose nomenclature. Thus we find such non-bulbous plants as Aconites, Anemones, Dahlias, Dicentras, Day-Lilies, Hepaticas, Solomon's Seal, Astilbe japonica, Tropæolums, Lily of the Valley, Corydalis, Torch Lilies, Pæonies, Christmas Roses, and many others described as "bulbous" plants, while some that are really so, and worthy of cultivation, are not even mentioned.
Some of the plants referred to above have thickened stems or roots, and will be found described in their proper places in the companion volume to this—"Beautiful Garden Flowers." They belong to several different families of plants. True bulbous plants, however (with which we may include those having "corms"), are confined to very few families. Indeed, they are restricted to one of the two large groups of flowering plants, viz., that in which the leaves usually have parallel veins, and the flowers have their parts in circles of three or six. This group of plants is known to botanists as "monocotyledons," and is still further distinguished by having only one seed-leaf, as may be seen when the seeds of any of them sprout, as shown in the Tulip, [p. 35].
It is within the limits of this definition, therefore, that all the plants described in this book come. They all have parallel-veined leaves, and the parts of their flowers are in "threes" or "sixes," as may be seen by consulting the coloured plates.
PLATE 3.
There is an apparent contradiction to this rule in the Daffodils (Narcissi) in which the "trumpet" or "corona" in the centre makes a seventh organ. A similar growth may be seen in such bulbous plants as the Eucharis, Hymenocallis, Pancratium, &c., that are usually grown under glass. This corona is analogous to the ligules or scale-like outgrowths so noticeable on the petals of the Campions (Lychnis), the chief difference being that in the Narcissi the ligules are joined together, become much larger, and often constitute the most attractive feature of the flowers.
Definition of a "Bulb."—Perhaps the very best-known example of a true bulb is the common or garden Onion. Another example is shown in the sketch of a Hyacinth and Tigridia.
| Tunicated Bulb of Hyacinth in section showing "Disc," and Scale Leaves s. l. | Tigridia Bulb, Showing thick Contractile Roots. |