70 LEJEUNEA. 
cells, with irregularly thickened walls, in a single stratum, or partly— 
especially towards the middle of the valves—in two or three strata; and 
it does not reach down quite to the base of the valves. In all cases the 
surface is unequally papillose, and as it were, spongy.* 
The elaters are almost exactly like those of Frullania in form and 
position, but they vary greatly in number, even in the same subgenus, 
although apparently constant in each species. In Bryopteris filicna 50 
have been counted on a single valve, in Br. diffusa only 30; and some of 
the minuter Lejewneew have only 6 or 7—some even only 5—on a valve. 
The included fibre is simple— very rarely bipartite—thin, broad, and 
rather closely twisted; in a few species, however, of which our L, calearea 
is one, the most powerful instruments fail to show any twisting, but only 
an undulation, The Spores are large, globose (;™™ in diameter) or 
oblongo-globose (34; x 35 or x ay™) , polyhedral by mutual pressure, but 
losing their angles “when steeped long enough ; the sporoderm tubercu- 
lose or warty; the nucleus greenish in the fresh state, but turning yellow- 
brown. 
Many dioicous and some monoicous species are, when sterile, repro- 
duced by gemme or “ propagula,” which are round or oval disks (quite 
like the first growth from the spore of Anthoceros t), springing from one 
or more mar ginal cells of the leaves, and increasing in size mainly by the 
bisection of their peripheral cells until they become 6 or more cells broad, 
when they develop a minute branchlet with a pair of rudimentary leaves 
from their margin, and drop off, to begin a separate existence. Adventi- 
tious ramuli are rarer, but are produced occasionally, even in the minutest 
species, ¢.g., in those of the subgenus Drepanolejeunea, where they spring 
from the surface of the leaves, or from any part of the branches. They 
bear very minute leaves, often reduced to the basal sac. 
The subdivision of this vast genus, whether into so-called genera or 
into sections, has not hitherto been attempted on the basis of a thorough 
study and comparison of all the species. The few “genera” separated 
from it by the authors of the ‘Synopsis’ are like morsels chipped off a 
block of marble, and reduced to something like symmetry, but leaving 
the remainder a somewhat rude conglomerate, although it really includes 
many other well-marked groups—some of them of greater value than 
those already struck off—and admits of being divided throughout into 
natural subgenera (or genera, for those who prefer to so re gard | them). I 
will briefly review the genera carved out of Lejewnea by the authors of the 
‘Synopsis,’ premising that all have entire underleaves except the last 
(Omphalanthus), which comprises both holostipous and_ schizostipous 
species. 
Their first genus, Bryopteris—previously proposed by Nees (Hep. Eur. 
ITI.) asa subgenus of Frullania—is a natural group enough, distinguished 
by the robust closely-pinnate stems (with subopposite branches) springing 
from a creeping caudex ; the 9 flowers on very short and perfectly simple 
ramuli ; the trigono-fusiform perianths ; the very numerous elaters, and 
other characters. An aberrant member is Br. diffusa, which is dicho- 
tomous throughout, except that the branches are still pinnulate with the 
? flowers as in the type-species, Br. filicina (Hook.), to which the leaves, 
* Of Archilejeunca nine n. sp. I have noted: Capsula facie 
interna crebre papillosa, papillis plurimis brevibus, aliis autem in pilum fere 
elongatis. 
+ Cf. Hofmeister, on the Higher Cryptogamia, Tab. i. 
