14 Cavers: Notes on Vorkshire Bryophytes. 
J. hutchinsine as ‘rocks and stones over which water trickles, 
and very moist places in shaded situations near waterfalls,’ and 
Spruce gives a similar habitat for the South American plants 
referred to this species. In the numerous British and South 
American specimens I have examined, the lobules though 
varying considerably in form, even on the same branch, are 
flat or slightly concave, strongly recalling the young lobules 
of /. dilatata and F. tamarisct as well as the mature lobules 
of Frullanias cultivated in very damp surroundings. In the 
Hawaiian species, /. piligera, described and figured by Evans, * 
the lobules are mostly of the pitcher type, and this species 
grows ‘on the ground and on trunks of trees in damp places,’ 
resembling in habitat the pitcher-bearing /rudlanzas and not 
the thoroughly moisture-loving /. hutchinsine. 
Water-storing arrangements of various kinds exist in several 
genera outside of Frudlanza and its allies, but well developed and 
stalked cylindrical pitchers of the /7//anza type are rarely met 
with in other genera. One of the few examples is the genus 
Polyotus (Lepidolaena) which is restricted to the temperate and 
cold regions of the Southern Hemisphere. In this genus (Fig. 5) 
the pitchers are developed more freely than in Aru/lania,; each 
sideleaf usually has a pair of pitchers, and they are sometimes 
borne on the underleaves as well. 
In Frullania the stem consists of uniform cells, and is some- 
what flattened above and below; the number of cells rarely 
exceeds ten in the median horizontal plane (Fig. 3). The leaves 
are only one cell in thickness, except at the base, where they 
are often two-layered close to the junction with the stem. The 
cells are about uniform in size and shape, but in /. ¢amarisct 
and /. microphylla there is usually a line of longer and wider 
cells along the middle of the upper lobe, which doubtless serves 
the function of a mid-rib, and in /. fragi/zfolia similar cells 
occur singly or in groups. Each cell contains several chloro- 
plasts lying in the layer of protoplasm lining the cell wall, and 
numerous oil-bodies occur in the central part of the cell. The 
originally thin and colourless cell walls usually become strongly 
thickened, especially at the angles, and deeply stained red, 
brown, or purple. The outer walls usually project somewhat, 
especially on the upper side of the leaf; these projections are 
usually well marked in /. ¢amarisct, and doubtless give this 
species its characteristic glossy appearance. The lateral 
* The Hawaiian Hepatice of the tribe /ubuloidee. ‘Trans. Connecticut 
Acad.’, 1900, p. 407. 
Naturalist, 
