2. = REVUE BRYOLOGIQUE 
perichætial leaves : Operculum very small consisting of little 
beyond the beak, which is but slightly enlarged at the base, 0,35 
to 0,40 mm. long, dehiscing under pressure at maturity : Calyptra 
_asin W. crispa: Cells of the exothecium ehortly rectangular or 
 quadrate with rather thicker walls than in W. crispa, mostly 
0,040 to 0,055 mm. long and 0,031 to 0,040 mm. broad, irregu- 
- larly interspersed with a few longer cells, up to 0,063 mm. in 
length, smaller towards the mouth, where there are about two 
rows of very small incrassate cells : Stomata few and difficult to 
trace at the base of the capsule. There is no trace of a peristome, 
but portions of a membrane covering the mouth are visible, as 
in W. microstoma, on the dehiscence of the operculum. Spores 
0,015 to 0,018 mm. in diameter, reddish brown and rather coar- 
_ sely papillose. 
= Hab : A rough stony field on the chalk hills near Lewes, Sussex. 
Capsules mature about the end of March. : 
I did not find any trace of reciprocal h ybridity, such as I found 
in the hybrids between W. crispa and W. crispala, but the mate- 
rial examined was unfortunately very scanty. a. 
The influence of W. microstoma on the hybrid capsules is 
__ Shown in their more elongate form, the longer seta, the readier 
dehiscence of the operculum, the membrane partially covering 
the mouth, the rather more elongated cells of the exothecium and 
the slightly larger spores. These modifications, though compara- 
tively slight, affect all the characters and show, if we accept 
Dr Weismann's theory, a fairly equal distribution of the elements 
of the germ plasm of the two parents, though there is a distinet 
preponderance, as in the case of the other hybrids described by 
me, of the influence of the mother plant. 
The use of the term « hybrid » as applied to these capsules and 
others due to a similar origin has been questioned and no doubt 
they are not exactly änalogous to the hybrids among the flowe- 
ring plants. It has further been suggested that the term should be 
reserved for the plants, which may result from the germination 
of the spores of such capsules. The existence of such mosses, 
however, though ambiguous forms, such as the interesting Grim- 
mia glauca recently described by M. Cardot (Rev. Bryol. 1905, 
_ p.16), have had such an origin -suggested for them, has never 
… been definitely proved. Since I do not think that any ambiguity 
is involved in the use of the term hybrid for the capsules under 
discussion and il is, in my opinion, preferable to describing them 
as distinel species, L have adhered to my former usage. 
Fe W.-E. NicuoLson. 
Lewes, 17 th November 1905. 
