278 MR. F. STEPHANAS REVISION OP 



female, inserted on small postical brandies which do not spring 

 from the centre of the midrib, but sideways on it, and have an 

 axis which stands at right angles to that of the parental frond. 

 The ramification is therefore a lateral one ; if these plants were 

 not frondose Hepaticse provided with an unbroken wing in place 

 of leaves, this would have been recognized long ago. Hyme- 

 menophytum phyllanthus, which has a creeping undivided frond, 

 is best adapted to study the origin of these fertile branches. 



H. flabellatum, which has a dichotomous frond, is sometimes 

 described as having the flowers (instead of saying branches) 

 springing from the forks. This is not the case ; the midrib is 

 dividing before fertile branches are developed, which stand in 

 the angle of the forks, distant from the brown central fascicle of 

 the midrib, in which they materially differ from Sy?nphogyna and 

 all other frondose Hepaticse, Metzgeria excepted. This last 

 genus, though differing much in general appearance, is never- 

 theless the nearest ally of Uymenophytum ; for Metzgeria, too, 

 has lateral fertile branches (the sterile postical branches spring 

 also from the side of the midrib in both), on the antical 

 side of which pistillodia and antheridia are inserted ; both have 

 a midrib with an axial fascicle of long and narrow cells; in 

 both genera the female flower is protected by an annular de- 

 pressed involucre which surrounds the young flower and becomes 

 bivalved in Uymenophytum ; while in Metzgeria only the apical 

 valve is well developed, the postical part consisting of a semi- 

 annular row of cells. 



This involucre is closely united with the little branch on which 

 it is inserted ; so that only longitudinal sections will give a view 

 of all this. 



In Metzgeria I have seen it most clearly on a species from 

 Australia (M. australis, Steph. in Hedw. 1889, p. 266). More 

 of this can be found in my paper on "Hepaticae Australiae," 

 in the place cited. 



Of Uymenophytum three species are known, viz. H. flabella- 

 tu?n 9 leptopodum, and phyllanthus. Dr. Schiffner, in the Botany 

 of the 4 Gazelle ' Expedition, published a fourth one (Podomi- 

 trium majus), of which he has examined a fruiting or flowering 

 specimen. His description of the vegetative organs ends with 

 the remark: u Involucrum femineum ut in Podom. phyllanthus. 



This is rather scanty for a plant to which he has given a new 

 name, and of which certainly as much of a detailed description 



