Phytogeographical Excursion in the British Isles. 127 
Triticum litorale Host. ( =Agropyrum pungens auctt., non T. 
pungens Pers.) 
Duval-Jouve has shown that T. pungens Pers. is the hybrid 
between T. junceum and T. repens , and therefore the British plant, 
usually named Agropynun pungens R. and S. must bear the name 
T. litorale Host. It is a very characteristic species growing on 
rather old beaches where the soil is not bare sand, but somewhat 
clayey. I have never seen it on the Danish coasts and I doubt if 
it reaches as far north ; with us it is replaced by saline forms of 
7. repens L. ( T . litoreum Schum., etc.) and the polymorphous hybrid 
T. junceum x repens. 
We saw T. litorale in great quantities at Blakeney Point 
(Norfolk) and at different places near Portsmoth (Hayling I si.) and 
along Southampton Waters. At Blakeney Point and Calshot 
(Southampton Water) the hybrid T. junceum x litorale was also 
present, and at the first place perhaps also the hybrid T. litorale X 
repens. 
PoTAMOGETONAC^E. 
Potamogeton perfoliatus, var. lanceolatus Blytt. 
Perthshire, Loch of the Lows and Butterston Loch near 
Dunkeld. 
The form found in these two Scottish lochs answers well to the 
var. lanceolatus Blytt, described from Norway. 
PoLYPODI ACE/E. 
Polystichum lobatum (Sw) var. Plukenetic (Lois.) 
Ireland, Ballyvaghan (Glen Thna Mountain), limestone. 
The well known authority on Ferns, Mr. Christensen of Copen¬ 
hagen, has determined a curious form of P. lobatum , which super¬ 
ficially resembles P. lonchitis Roth, as given above ; it is the same 
as Mr. Druce (l.c. New Phyt., Vol. X, p. 323) names P. aculeatum 
Roth var. lonchitoid.es Deakin. 
The same authority considers the dubious form of Asplenium 
from Kynance Cove, the Lizard, referred to in Druce’s list as true 
Asplenium adiantum nigrum L. 
Salviniace^e. 
Azolla filiculoides Lam., with ripe microsporangia. 
The Azolla growing in abundance and fruiting in a little pond 
near a garden at Woodbastwick, E. Norfolk, is A. filiculoides Lam., 
not A. caroliniana Willd. as stated in Druce’s notes (New Phyt., 
Vol. X, p. 324). 1 
A . filiculoides is a species of American origin (mostly South- 
American) and it was introduced to Europe a long time ago ; it is 
now quite naturalized in West France (Cherbourg, Bordeaux, etc.) 
From A. caroliniana it differs in the more racemose branching 
of the fronds (not repeatedly pseudo-dichotomous) and the uni¬ 
cellular hairs on the upper surface of the upper leaves, as well as in 
microscopical characters which furnish a better distinction. 
1 As I did not collect the plant we saw in a pond near Queenstown 
Junction, Cork, I do not know if it is A. caroliniana or A. 
filiculoides. 
