105 
THE BRITISH SPECIES OF NAJAS. 
By A. B, Renpuz, M.A., D.Se. 
(Puate 408.) 
In the Journal of Botany for 1864 Alexander Braun published 
the first modern systematic account of the genus Najas. At that 
time it was represented in our flora by one species, N. flewilis, 
which had been found by Professor Daniel Oliver in Connemara 
in 1850. Since 1864, the occurrence of N. flewilis in Scotland, the 
discovery of N. marina by Mr. Arthur Bennett in a Norfolk broad, 
and the establishment of the tropical species V. gram in 
hester canal have been record d two species 
fully deseri and figured in this Journal. Mr. Cle Reid’s 
was formerly more widely distributed in England than at present, 
and have also quite recently added two new ones to the list of 
British species—namely, N. minor All. and N. graminea Delil. 
As it seems likely that N. minor may be growing somewhere in our 
islands at the present day, a plate has been prepared showing the 
habit of the plant, and also enlarged figures of its flowers and 
fruit. These are all drawn from South German specimens; the 
and its species; it may, however, be of use to give here a shor 
account of the four species which we may now claim as British. 
Najas is of world-wide distribution, occurring, except in the 
frigid zones, in suitable localities in almost every botanical region. 
It grows completely submerged in fresh or brackish water, generally 
in ponds, lakes, or rivers. ere are thirty-one known species, 
which fall into two well-marked subgenera—Eunasas, including the 
single widely-distributed NV. marina; and CavuLINIA ( separated as a 
genus by Willdenow), which includes the remaining thirty. he 
sented by the three remaining British species. The other section 
is a small one confined to the warmer parts of the Old World, and 
ope. Our British species, though few, are 
therefore highly representative of the genus. They may be at once 
distinguished by leaf-characters, as will be seen from the following 
clavis :— 
Internodes and backs of leaves spine-bearing . WN. marina. 
nternodes and backs of leaves smoo 
Marginal leaf-teeth conspicuous . 
Marginal leaf-teeth inconspicuous. 
-sheaths sloping . . + + + 
Leaf-sheaths auricled . . - - + + 
Journat or Botrany.—Vot. 38. ([Aprit, 1900.) I 
N. minor. 
N. flexilis. 
. N. graminea. 
