Tasmanian Bryophyta

Abstract

Hepatics. The second class into which the Bryophyta are divided is a purely natural one. There are no intermediate forms through which the two groups are connected, though their close relationship is very apparent. There is always a natural distinction, requiring no arbitrary line to separate them.The gametophyte is varied in structure ; many have the form of a flat, green plate, while the greater number develop leaves; yet when leaves are present these have a distinction of insertion and structure quite different from those of Mosses. Leaves are always placed in two or three rows, two lateral and one ventral, the latter row occasionally being absent. They are usually of delicate consistence, never have a midrib, and are often divided. Most Hepatics live only under permanently moist conditions, but some few can survive even the drying conditions of bare rock at a high elevation.The characteristic feature of Hepatics is that while they have the typical antheridia, archegonia and permanently attached sporophyte of the class, the sporophyte has attained a much further reduction than amongst Mosses.It is no longer a hard-tissued, persistent being, but is reduced to a comparatively evanescent organ. In most it is a simple globular or oblong dark capsule, which splits into four valves at maturity, borne on a long or short pellucid stalk. In Marchantia and its allies the stalk is almost absent. In Riccia. reduction has reached its limit, and the sporophyte is reduced to a spherical spore sack, buried in the substance of its parent. One order of Hepatics, of which Anthoceros is the type, has a sporophyte of less reduced character than the rest, but still of a form not to be confused with that of a true moss; the shape is long and slender, and it splits from top to base into two valves.It is green, and still bears efficient stomata on its surface.Hepatics may be sorted into three perfectly natural Orders :— Marchantiales, Jungermanniales, Anthocerotales.This article describes the genera, including locations they are found. An index of genera is given at the end.

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