408 
C. E. Moss. 
from the Isle of Wight; and this plant also has its leaves doubly 
serrate, the leaves of the barren stem strongly cordate, and the 
flowers more numerous in each verticillaster. 
“ Polygonum nviculare L.” (agg.).—The forms of this excessively 
variable “ species” were frequently discussed on the excursion. It 
was a great advantage to have Professor Lindman at hand, for he 
probably knows more about the forms in question than any other 
botanist. Quite recently, Professor Lindman (in Svenslc. Bot. 
Tidskrift , vi, iii (1912) ) has published his mature views with regard 
to them. He divides the aggregate “ P. aviculare L.” into two 
species, P. heterophyllum and P. ceqnale ; and a third allied plant 
he had previously described as P. calccitum. 
P. heterophyllum Lindman op. cit., p. 690.—Common, chiefly 
in arable land, as far north as Forfarshire (!) at least. 
P. heterophyllum var. angustissimum Lindman op. cit., 
p. 691 ; P. aviculare var. angustissimum Meisner in DC. Prodr. xiv, 
98 (1856).—This has been drawn for the Cambridge British Flora 
by Mr. Hunnybun, from Huntingdonshire specimens. Probably it 
is not uncommon. 
P. heterophyllum subsp. rurivagum Lindman loc. cit. ; P. 
rurivagum [Jordan ex] Boreau FI. Centr. France ii, 560 (1857). This 
is very abundant in chalky cornfields, e.g., in Cambridgeshire. It is 
usually described as an erect plant; but, like all forms of “P. 
aviculare L.,” it is prostrate or decumbent at maturity. Almost every 
form of “ P. aviculare L.” has its small-leaved and small-fruited 
form ; and the latter are often named “ P. microspermum." 
P. heterophyllum var. litorale Lindman loc. cit. ; P. litorale 
Persoon Syn. i, 439, 385 (1805) non Meisner.—This is a hemi- 
halophytic form, the P. aviculare var. litorale of many botanists. 
P* heterophyllum var. caespitosum Lindman loc. cit .; P. 
avicidare var. depressum Meisner in DC. Prodr. xiv, 98 (18 ) partim. 
Recorded by Professor Lindman from near Cambridge. 
P. requale Lindman op. cit. p. 692. Common, as far north 
as Forfarshire (!) at least, chiefly by waysides. 
Professor Lindman points out that the plants are visited by 
small Diptera, and suggests that hybrids occur. This suggestion 
is, in my view, a very reasonable one. 
P. calcatum Lindman in Botan. Notiser 139 (1904).— 
Professor Lindman last year sent me specimens of this plant; and 
I had no difficulty in recognising it, when 1 saw it on Arthur’s Seat, 
near Edinburgh, last September. I sent a number of my specimens 
