51 



TASMANIAN BRYOPHYTA. 



By L. Bodway, 



(Read lOtli July, 1916. Issued separately SOtli Aug., 1916.) 



HEPATICS. 



The second class into which the Bryophyta are divided 

 i:, 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 fiat, 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 occasion- 

 ally being absent. They are usually of delicate consist- 

 ence, 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 perman- 

 ently 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 re- 

 duced 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 re- 

 duced character than the rest, but still of a form not to 

 b(' 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 : — 



Mahchantiales, 



jungermanniales, 



Anthocerotales. 



