(from the small one with which I commenced), the stout stem becomes naked below, sparingly leafy upward, with long, linear, coriaceous, acute or obtuse leaves, the capsules are both axillary and spicate, but the spike is interrupted, the scales being at one time small, and at another foliaceous. This approaches the L. taxifolium, Sw., and L. linifolium, L., natives of various parts of the world, also L. gnidioides, L., Cape specimens of which differ from the normal state of varium only in having axillary capsules, whilst in other localities it becomes pendulous and spicate; and so with regard to the L. Flagellaria, Bory, of New Zealand, which I cannot distinguish, except by its mode of growth, from L. varium. To dwell at length upon all the varieties of this species would be out of place here, and occupy many pages; the transitions from it to Phlegmaria are not obscure, the variations of that plant being excessive.
The importance of the question, "whether two perfectly similar plants, from remote quarters of the globe, are to be considered as belonging to one species," has induced me to canvass very fully the claims of many supposed forms of Lycopodium to the title of distinct species. In all such cases, my first object has been to determine whether the plant inhabits various intermediate countries. When, as is the case with Callitriche verna (p. 11.), Montia fontana (p. 13.), Gentiana prostrata (p. 56, in note), Myosotis fulva (p. 57, note), and Trisetum subspicatum (p. 97.), they are found to do so, there need be little hesitation in referring them, after due examination, to one plant; in such instances, the supposition of a double creation of the same species, or of one of them being a variety of some other really distinct plant, which plant wholly resembles another from other countries, would be confessedly a gratuitous assumption. Where however no intermediate stations can be detected, these suppositions become more plausible; the only alternatives to such conclusions being, 1st, the possibility of the species being destroyed in the intervening positions which it may formerly have inhabited; 2nd, the great improbability that the seed has been carried at once from one polar region to the other; or, lastly, what I have endeavoured to establish with regard to Lycopodium varium and Selago, that the species does exist in all intermediate latitudes, but in a hitherto unrecognised form; a circumstance the less to be wondered at on many accounts, and the following in particular. Our daily increasing knowledge of Ferns proves that the species are infinitely more widely distributed than has been supposed. The several species being variable in limited areas, it is to be expected that the amount of variation should increase proportionally with the space they cover; because the individual species of many widely distributed genera, as Lycopodium, have often themselves wide ranges; because the lower we descend in the scale, according to which all known vegetable productions are now arranged, the more universally we find the species scattered over the surface of the globe; and lastly, the minute size and abundance of the sporules of Lycopodium are favourable to their extended dispersion.
Theca quadrifida, rarius octofida; valvulis apice operculo persistente connexis. Calyptra mitræformis. Vaginula apophysiformis, setam brevissimam occultans, demum stipitata.
The peduncle, which elevates the mature capsule in this genus, is nothing more than an elongated receptacle (pseudopodium, Brid.) of a white colour; such as is also found in Sphagnum. In an early stage, this receptacle scarcely differs in appearance from that of other mosses; by its subsequent elongation the theca is elevated, generally above
- ↑ I here most gratefully acknowledge the invaluable assistance afforded me in the more complete determination, and in the diagnoses and descriptions, of the mosses, by our old and valued friend William Wilson, Esq., of Warrington; whose accuracy in botanical, and especially in microscopical investigation, and knowledge of this tribe of plants, are beyond praise.—J. D. H.
