36 THE BOTANICAL EXCHANGE CLUB OF THE BRITISH ISLES. 
“ It is not very easy to give a name to your Roxburgh plant further 
than that suggested in my footnote. Some of the larger foreign 
specimens of P. decipiens come very close. From P. salicifolius , 
Wolfg. ! of which we have the type here, it differs in the more rounded 
base and more obtuse apex of its leaves, but might pretty well go to 
it.” Through the kindness of Dr. Boswell, I have examples of P. 
nitens from four different localities. The Tweed and Teviot plant 
differs from all these, and is also very different from Mr. Ley’s 
Herefordshire P. salicifolius , distributed through the Club (see 
Report, 1877, p. 10 ). — Andrew Brotherston. A dubious plant, 
and it is not easy to . give a name without fruiting specimens. I 
cannot think it comes under P. nitens. It approaches specimens 
named P. undulatus , Wolfg., and in its peduncles and spikes it 
resembles P. salicifolius, Wolfg. — Arthur Bennett. 
Polamogeton heterophyllus , Schreb., form with broad-based sub- 
merged leaves. Kirbister Loch, Orkney, July, 1875. — J. T. Boswell. 
Potamogeton zosterifolius, Schum. Canal, Warwick, 1877. — 
R. L. Baker. 1878. — H. Bromwich. 
Potaniogeto?i pectinatus, L., genuinus. Loch of Kirbister, Orphir, 
Orkney, August, 1880.- — J. T. Boswell. 
Potamogeto?i filiformis , Nolte. Mud at bottom of brackish water 
near the Bridge of Brogar, Loch of Harray, Orkney, 24th September, 
1880. — H. Halcro Johnston. 
Zaimichellia polycarpa , Nolte, var. tcnuissima, Fries. Kirbister 
Loch, Orphir, Orkney, August, 1880. — J. T. Boswell. 
Ruppia rostellata, Koch, var. nana tnihi. In the Oyce of Firth, 
Orkney, August, 1880. Stem creeping, wholly buried in the mud, 
which is covered by the sea at high water. Peduncles very short, 
curving downwards, so as to bury the fruit in the silt ; stalks of the nuts 
usually shorter than in the ordinary form of R. rostellata, but many 
times longer than the nuts ; nuts very oblique and rostrate, as in 
R. rostellata ; leaves setaceous ; sheaths not swollen. This plant is 
much like No. 205 of Balansa’s ‘‘Plantes d’Algerie,” 1852, named 
Ruppia maritima , var. acaulis, J. Gay, from “ Bords de la Macta, 
dans une mare d’eau salee,” but that has the nuts nearly regular, 
greatly swollen, and not rostrate ; indeed, they are very like those of 
R. Drepane?isis , Tineo, which I' have from Sicily. The Orkney plant 
has some resemblance to R. brachypus , Gay, but has shorter stems, 
narrower sheaths, and much longer, stalks to the nuts, which are less 
swollen and distinctly rostrate. — John T. Boswell. 
Zoster a angustifolia , Reich. Oyce of Firth, Orkney, August and 
September, 1880. — J. T. Boswell and H. Halcro Johnston. 
Alisma lanceolata , With. Coleshill Pool, Warwickshire, Sept., 
1876. — H. Bromwich. Not la?ueolata, With. — J. G. 
Iris Pseudacorus , L. Swampy meadow, Kelvedon, Essex, June, 
1880. — E. G. Varenne. This appears to me to be the I. pseudo- 
Acorus, Boreau, Flore du Centre, 3 me ed., tome 1", p. 635. Botanical 
Exchange Club Report, 1878, p. 19. /. acoriformis , Bor., the more 
widely-distributed and common form, is readily (as far as my experi- 
ence goes) distinguished by the different colour and shape of its 
outer perianth-segments and the much broader stigmas. To do 
justice to the critical forms of Iris, a flower, to accompany each 
