Jf 
NOTES ON YORKSHIRE BRYOPHYTES.* 
IV. Frullania and Jubula. 
E. CAVERS, DSc bles, 
Professor of Biology, Hartley University College, Southampton. 
Tue genus Frudlania, one of the most sharply defined and easily 
recognised among leafy liverworts, is represented by over 300 
species, the great majority of which are tropical. Only six 
species occur in Europe; five of these are found in Britain, 
and four in Yorkshire (/. délatata, F. tamarisct, F. microphylla, 
F. fragilifolia). The two first named are the commonest, 
and they are perhaps the most elegant of our native liver- 
worts (Plate V.). Most of the species of Arullania grow as 
epiphytes on bark of trees, but some grow on rocks; for 
example, /. dilatata is nearly always found on trees, whereas 
F. tamarisct appears to grow most frequently on rocks, though 
also found sometimes on trees. Our native species often form 
fairly large matted layers, the overlapping branches being 
closely pressed to the substratum, but in some tropical species 
the plants hang from the branches of trees in ‘huge masses, 
sometimes half a yard long, and too bulky to be grasped in 
the arms.’ + 
The genus /ubu/a has a curious geographic range. The 
type-species, /. huéchinsi@, was discovered in Ireland, and 
besides occurring in several scattered Irish localities, plants 
more or less varying from the type have since been found 
along the western side of England, Wales, and Scotland, and 
a few years ago in West Yorkshire. /wbu/a apparently occurs 
nowhere else in the temperate regions, but it has a wide dis- 
tribution in the tropics, especially in Central and South America. 
Further reference will be made to this genus, which is by some 
writers merged in Frudlanra, though it stands well apart from 
the latter in many respects. The greater part of this paper, 
however, deals with Frul/anta, especially /. dtlatata and 
F. tamarisct, abundant living material of which was available 
for investigation. 
In Frullania, as in leafy liverworts in general, there is a 
main axis bearing lateral branches in two opposite rows, and 
both main axis and branches consist of a cylindrical stem from 
which arise two rows of sideleaves and a single row of under- 
* For previous articles see the ‘ Naturalist’ for September and November, 
1903, and July and August, 1904. 
+ Spruce, Hepatice amazonice et andine, p. 38. 
1907 January rt. 
