ON BRITISH SPECIES OF ISOETES. 3 
“Expédition ‘scientifique.’ Although I could not have the slightest - 
doubt concerning the name of the plant, I took an opportunity of 
sending specimens to France, and obtaining from M. Durieu de Maison- 
neuve, the first describer of the species, and M. J. Gay, the next best 
authority on the genus, a confirmation of my nomenclature. I need 
not enter into a discussion of the characters of the plant, for they are 
given, to the best of my ability, in the last edition of my * Manual ;’ 
and a good illustration of it, under the mistaken name of J. Duriei, is 
to be found in Hooker's * British Ferns? (t. 56). Nevertheless, it may 
be well to remark that the maerospores of I. Hystrix are bluntly tuber- 
cled, whilst those of 7. Duriai are “ fortement! et profondément scrobi- 
eulées ;" that is to say, the whole macrospore is covered with a net- 
work of elevated lines with deep hollows between them in I. Duriei, 
and with minute blunt tubercles in J. Hystrix. It is true that a 
tolerably high magnifying power is required to show these structures ; 
but of course that does not detract from their value. We may reason- 
ably hope that this curious plant will be found in Devon or Cont- 
wall before many years have passed. 
I now turn to the other addition to our flora,—a true addition, since 
it is found in England and Scotland. On August 6, 1845, in com- 
pany with Dr. Balfour and a small party of students, I visited Loch 
Sloy and Ben Voirlich, near Loch Lomond, in Scotland, and gathered 
what I then called Z. /acustris in a little pool near to the top of the 
mountain. In 1847 I collected a plant, also then called Z. lacustris, 
in the river that runs out of the lakes at Llanberis, in North Wales: 
on that occasion in company with my friend Newbould. At an earlier 
time Mr. W. Wilson gathered a specimen of the same plant as those 
just mentioned, in * a pool near Llyn-y-Cwn,” near Llanberis. The bo- 
tanical guide, John Roberts, calls this pool Llyn-y-Cwn-bach. The 
specimens remained wrongly named until 1860, in which year I sent a 
considerable number of specimens of Isoétes to M. Gay, at Paris. By 
letter, dated September 5 of that year, he informed me that my speci- 
mens proved that there were two species in the country surrounding 
the village of Llanberis, namely Z. lacustris, Linn., and I. echinospora, 
Dur. He also kindly gave me the requisite information by which to 
know them. T thereby determined the true name of the Scottish 
specimens and that found by Mr. Wilson; but, to render assurance 
doubly sure, I sent them to M. Gay, who showed the whole collection 
B 2 
