Gardeners Chronicle & New Horticulturist, ns.  5: 665-666 (May 20, 1876)
Lilium species

In the last two numbers of the Annates des Sciences Naturelles M. Duchartre has published his remarks on the bulbs of certain Lilies, in continuation of those which he made in 1872 on the bulbs of L. Thomsonianum. In the present communication he speaks of the mode of development of the bulbs of Lilium giganteum and L. cordifolium, as well as of the germination of sundry other species, such as L. auratum, callosum, Szovitzianum, tenuifolium, and Thunbergianum. We hive no space to do more than give a summary of M. Duchartre's conclusions, which show that there is a great diversity in the first development of the species and the formation of their bulbs, even in the case of very nearly allied species.

1. In some species the germination is rapid, in others slow. The first are usually plants of small dimensions, which flower three or four years after germination, such as L. tenuifolium and L. Thunbergianum; the latter, of slower growth, are plants of larger size, with bigger bulbs, such as L. giganteum, L. cordifolium, L. auratum, &c. In the one case a few weeks are sufficient for the germination of the seed, in the other a year or even two years are required.

3. Lilies which germinate and grow rapidly produce during the first year three or four leaves in addition to the seed-leaf or cotyledon; on the contrary, those species which germinate and grow slowly only thrust their seed-leaf above-ground during the first year. The first ordinary leaf only appears in the second year, during which time it remains usually solitary, or, less commonly, the young plant developes two or three leaves in the course of the second year, as in L. auratum. According to M. Max Leichtlin, in L. monadelphum and L. Szovitzianum the seed-leaf or cotyledon is not raised at all from the soil, save as a little scale, and M. Duchartre says that L. speciosum and L. polyphyllum germinate in a similar manner.

3. In all Lilies the radicle in the first stages of germination developes into a well marked pivot (taproot), but while in most of the species the activity and even the existence of this pivot are limited to the first year, as in L. giganteum, L. auratum, L. Szovitzianum, L. tenuifolium, and L. Thunbergianum, in other species the activity and development of this portion of the seedling are continued during the second year, as in L. cordifolium and L. callosum. This important physiological difference may be manifested in species very nearly related to each other, such as L. giganteum and L. cordifolium.

4. In the great majority of Lilies the "tigellum" does not sensibly develope after germination, but in L. giganteum it forms a hypocotyledonary axis (i.e., a portion of stem below the seed-leaf) of three millimetres in length.

5. L. giganteum is the only species yet observed in which two generations of adventitious roots are produced in succession, the first arising from the base of the tigellum and disappearing with it; the second forming at the base of the little bulb which is formed, and multiplying rapidly as the latter increases in size. In the other species, where the tigellum remains rudimentary, the first of these generations of adventitious roots is, of necessity, wanting.

6. The first appearance of the bulb is always due to the notable growth in thickness of the sheathing portion of the seed-leaf or cotyledon.

7. The sheath of the cotyledon remains throughout the first year, and in the larger species it remains fresh during a longer or shorter period of the second year. During all this time the gradual increase in size of the young bulb is principally due to the thickening of this sheath.

8. The internal parts of the young bulb only contribute, in the first instance, in a very small degree to the increasing thickness of the bulb; but when the sheath of the seed-leaf is exhausted and withered, then they gradually increase, so as ultimately to constitute the mass of the bulb, and develope, some into leaves, others into nourishing scales, the size increasing till a flower-stem is produced. When the flower-stem so formed is terminal it dies after fructification, and the bulb is then annual or monocarpic. But when the flower-stem originates from a lateral or axillary bud, and it therefore constitutes a branch, several may be produced year after year, and the bulb then becomes perennial or polycarpic.