The globose capsule of Targionia is situated on the lower surface of the frond; and at maturity splits verti cally into two hemispherical valves. It contains nume rous very minute seeds, combined by threads into a dense globular mass. In this genus elateres, or seed dispersers, are altogether wanting.
The pericarp of Sphxrocarpus is unknown. In the bottom of the calyx, there appears at maturity a dense mass of extremely minute seeds, combined into a glo bular form by numerous threads, as in Targionia. In glauca the capsule, having. emerged sonic time before maturity from the substance of the frond in which the germen was lodged, appears of a roundish form. At maturity thc upper part of the capsule separates, and a mass of dark-Loloured seeds comes in view. This is the only known hepatic moss, having an obvious pericarp, which is not valvular.
Seeds of Hepatic Mosses.
These vary much in form, size, surface, and colour, in different genera, and even species of the same genus. In Jungermannia, they are usually spherical ; but in J. ser pyllifolia, J. minutissima, and J. calyptrifolia, they are oblong, somewhat angular in the two latter; in J. ept phylla, thcy are irregular in form, but usually more or less oblong or ovate. In size they vary very much, some times a small capsule containing a great number of seeds, while a much larger one contains comparatively few. And, as in the foliose mosses, some of the minutest spe cies are noted for the largeness of their seeds. Thus J. minutissima and J. calyptrifolia, two microscopic spe cies, have both large seeds compared with the size of the plants and of the capsule ; while in J. Trichomanis thcy are small and numerous. Their surface is usually smooth ; yet in J. Hutchinsix, they are marked with spots which appear to be minute tubercles; in J. dila tata, and J. Tarnarisci, they are tuberculated ; and in J. pusilla, they are echinated. Their colour is usually some shade of brown, varying from yellowish-brown to olive-brown ; but different shades of green are also far from uncommon. In the capsule, as NVCII as when fall ing out, they usually appear quite separate and uncon nected; but those of J. Hookeri, and J. Blasia, are usu ally enveloped three together, in a pellucid membrane. In J. Blasia, parcels of two, and of four arc also found within one membrane ; and it seems to give way before the escape of the seeds as they fall out separately. In J.
Hookeri the membrane is no longer visible when the seeds are quite mature ; yet as they usually fall out in threes, it seems probable that the membrane continues to exist.
In 'Marchantia also, the seeds are of a spherical form, at least in the species polymorpha and conica, the spe cies which come most frequently under observation in this neighbourhood. In M. conica, their surface is co vered with minute spots, which probably are tubercles.
The seeds of Monoclea and Anthoceros are also near ly spherical. In Monoclea their surface is smooth, in Anthoceros it is echinated.
The seeds of Riccia glauca appear, at an early period, like white smooth globules. When more advanced, they become flattened, of a greenish colour, surrounded by a pellucid white line. At maturity, they become dark brown, hemispherical, or in some instances nearly ovate, with a prominent point always at one, and sometimes at both extreinities.
The germination of the seeds of hepatic mosses has been observed in species of the two genera Jungermannia and Marchantia.
In Apfil 1780, Hedwig sowed some of the seeds of J. epiphylla, by shaking son-te of the mature capsules over a flowerpot, the earth in which had been properly pre pared for this experiment. After the lapse of a fcw days, they began to swell, and afterwards, from the narrower and lighter coloured extremity, a white, sitnple, and very pellucid root proceeded. The upper part of the seeds became at first reticulated, and afterwards they expanded into perfect plants. Thus it has been satis factorily proved, that in Jungerrnannia, the little gra nules contained in the capsules are really seeds.
On the germination of Marchantia, experiments were made by Neckar, as early as 1772. In 1779, Hedwig repeated the experiment with the seeds of M. polymor pha. Having. prepared a flowerpot, containing that sort of mould which he reckoned most agreeable to this species, and in a clue degree of moisture, he cau tiously shook over it some stellated receptacles. of which the capsules. were open. The pots were then covered with branches of boxwood, which had been well washed in spring-water. In eight clays aftcr the sowing, the whole earth in the flowerpot assumed a ”-reenish huc, afterwards distinct plants could be easily traced ; and in the following spring, both peltate and stellated receptacles were produced by them.