ae ee ee 
1912] Evans,— Notes on New England Hepaticae,— IX 5 
The true R. lamellosa is a species of the Mediterranean region, and 
all records of its occurrence in North America need careful inves- 
tigation. 
The thallus of R. Austini is of a pale glaucous green color and is 
apparently never pigmented with purple. It sometimes forms a 
complete rosette about 1.5 cm. in diameter but often fails to do so, 
and the plants then occur irregularly scattered or in more or less com- 
pact mats. The thallus forks from one to three times, the branches 
measuring 1.5-3 mm. in width and 3-4 mm. in length. The terminal 
branches taper gradually to blunt points. On the upper surface in 
the apical region a deep and narrow sulcus is visible, from which the 
flanks curve abruptly away. The sulcus is usually very short and the 
older parts of the thallus are plane or nearly so. The ventral scales 
are large, crowded and hyaline and project considerably beyond the 
margin of the thallus, thus forming a distinct translucent border. 
The margins of the scales are either entire or minutely and irregularly 
crenulate from projecting cells. The plant is quite destitute of 
marginal or surface cilia. In cross section the lower surface appears 
plane or slightly convex in the median region, while the sides ascend 
obliquely and meet the upper surface at a sharp angle of about 60 
degrees. The thickness of the thallus is usually from one fourth to 
one third as great as the width. The epidermis consists of colorless 
and rounded thin-walled cells, which soon break down. Their place 
is taken by the second series of cells, which gradually lose their green 
contents but retain their thin walls. 
Although the species is monoicous the capsules are not abundantly 
produced. In fresh material they are completely hidden until the 
tissue above them begins to discolor and to become disintegrated. 
The spores are brown and measure 85-100 u in maximum diameter 
The angles between the faces of the spore are rounded, and there is 
no wing developed at the junction between the convex face and the 
three triangular faces. The convex face is covered over with anasto- 
mosing ridges about 2 u high, which form a distinct reticulum, and the 
ridges do not project appreciably at the angles of the meshes. The 
latter number about nine across the face of the spore and average 
about 10 u in width. The triangular faces are marked with still 
lower ridges, irregularly arranged and not forming a network. 
The three related species, R. Austini, R. americana, and R. lamellosa, 
form a definite group characterized by a flat thallus destitute of cilia 
