148 
LASTREA. 
IIIS is a large genus, and one of almost universal distribution. In the 
“ Synopsis Filicum ” it is considered as a section of the genus Nephr odium, 
differing from the typical species of 
Nephrodium in having the veins all 
free, and about 200 species are enu- 
merated as belonging to it. Of these 
only seven come within the scope of 
the work, although our list will be 
found to include nine species of Las- 
trea, this discrepancy being due to the 
fact that we take a somewhat more 
liberal estimate of what constitutes a species than the 
authors of the “ Synopsis,” and hence regard as distinct 
three plants — Lastrea spinulosa, L. reinota , and L. dilatata 
— which are united under the former specific name in 
the work in question. Although varying a good deal in 
size, texture, and cutting, there is a general resemblance 
among the species of Lastrea, and we do not find among 
the extra-European species any that call for special notice. 
The general habit and style of the genus will be gathered 
from the detailed descriptions of the species which fall 
within our limits ; and as all the European species are 
also British, and some of them very common, our readers 
will not find it difficult to make their acquaintance in a 
living state. The genus was named Lastrea (or rather 
Lastrcea, which was its original form, that now in use 
being adopted when its application was somewhat changed), 
and commemorates a French botanist, M. Delastre. 
LASTREA THELYPTERIS, Bory. 
This is a fern of boggy and marshy ground, which, 
although very widely distributed in England, cannot be 
considered a common plant, while in Scotland it is un- 
frequent, and in Ireland rare and local, although found 
in many widely-separated localities. It is a delicate- 
looking plant, with soft, membranous pale-green fronds, and 
a long, very slender branched rhizome, by which character 
it is distinguished from the species most nearly allied to 
it. Our coloured figure, which is much reduced, shows this 
rhizome, upon which the fronds are produced at irregular 
Ai 
*v , / r t e r rrr\ 
ASK. 
/ 
'‘= 3 . 
(a) FROND OF LASTREA THELYPTERIS 
(^) UNDER-SIDE OF FERTILE PINNA. 
