4 ON BRITISH SPECIES OF ISOETES. 
to M. Durieu, and they concurred in stating that the plants from the 
two places near Llanberis and that from Ben Voirlich are T. echino- 
spora. In the spring of 1862, I obtained, through the kindness of the 
Rev. A. Beverly and Mr. W. Sutherland (both of Aberdeen), specimens 
of the Z. echinospora gathered in a lake not many miles from that city, 
and called by the two names of Loch Park and Loch Drum. "These I 
sent to Paris, and had my determination of them also confirmed. 
Having thus fully established the existence of the plant in England 
and Scotland, and convinced myself of the distinctness of the species 
from J. lacustris, I introduced it into the fifth edition of my * Manual,’ 
which was published in May, 1862. 
Soon after that date, I learned from M. Gay that he intended to 
visit North Wales for the purpose of examining Isoëtes, as he had re- 
cently done in Central France (of which journey a very full and inter- 
esting account will be found in the * Bulletin de la Société Botanique 
de France,’ viii. and ix.), and determined to join him in his search. I 
also persuaded my accurate friend Newbould to accompany me. The 
three arrived at Llanberis on August 13, and remained there until 
August 21, when we were obliged to leave M. Gay to complete his re- 
searches alone. We found J. lacustris to be exceedingly abundant in 
nearly all the lakes and mountain tarns of that district, and obtained 
I. echinospora in the places where Mr. Wilson and I had formerly ga- 
thered it, and in several other places in the neighbourhood. Z. echino- 
spora is by far the less common plant, and is never found except where 
there is peat at the bottom of the water. After a very little experience, 
assisted by the teaching of M. Gay, Mr. Newbould and I acquired fa- 
cility in distinguishing the plants when growing, and could lean over 
the side of a boat and select the T. echinospora with certainty. The 
spreading leaves (fronds) and pale green colour of it contrast well with 
the dark tint and usually erect leaves of J. lacustris. The plants some- 
times grow together, but, as T have already said, it is useless to look 
for I. echinospora in any place where the water does not rest — a 
peat soil. 
It now remains for British botanists to discover the distribution of 
these two plants in Britain. There must be more than two localities 
for it in Scotland; there probably are others in England and Wales, 
and surely it exists in Ireland. I have taken some trouble to obtain 
specimens from different places, but have not succeeded in acquiring 
