1913] Fernald,— Polygonum maritimum 71 
Nuttall’s P. glaucum has been forced to fit the Linnean definition 
as a perennial, but usually with apologies for its annual character 
on our coast. When, however, the plant has stood upon its own 
merits it has as regularly been described as an annual. In his experi- 
ence with the plant in the field the writer has never seen any reason 
to question Torrey’s original statement that P. glaucum is “decidedly 
annual," nor do the herbarium specimens available give any evidence 
that this is not the fact. 
When, however, we examine authentic material of Polygonum 
maritimum, the plant of the sands of the Mediterranean, but found 
locally northward on the Atlantic coast as far as the Channel Islands 
and possibly England, we find that, although it may sometimes 
flower as an annual or biennial, it is, as described by Linnaeus, Torrey, | 
and the Mediterranean botanists, ordinarily a suffruticose plant with 
stout branches 1.5-4 mm. thick at base, and usually closely invested 
with very conspicuous overlapping white hyaline stipules, which are 
1-2 em. long and have numerous (usually 12) nerves, the longest of 
which are 8-18 mm. long. The annual American P. glaucum, on the 
other hand, has the tough but scarcely ligneous branches only 1-2 mm. 
thick, the lower internodes commonly exceeding the stipules, which 
are only 7-10 mm. long, with the longest nerves only 5-8 mm. in length. 
In their extremes the measurements of these two plants slightly over- 
lap, but when good fruit is examined it is found that the European 
P. maritimum has achenes 4.5-5 mm. long, with faces 2.5-3.5 mm. 
broad; while the American P. glaucum has the achenes distinctly 
smaller, 3-4 mm. long, with faces 1.6-2.2 mm. broad. In view of 
this aggregation of characters there seems, then, no good reason for 
longer confusing the endemic American P. glaucum Nutt. with its 
cousin of southern Europe, P. maritimum L. 
'The other glaucous large-fruited and petaloid-flowered Polygonum 
of the sands, the plant which abounds on the Magdalen Islands and 
is found on the neighboring sands of Prince Edward Island, Cape 
Breton and western Newfoundland, has also had an unfortunate 
experience in maintaining its own identity. This plant, like P. 
glaucum, is an annual, but it has greener usually less revolute leaves, 
shorter and therefore less conspicuous stipules, only 4-8 mm. long 
and with the longest nerves 3-5 mm. in length; and its achenes are 
1‘* Very rare and perhaps extinct in England.... In the Channel Islands it is 
much more plentiful.” — Syme, Engl. Bot. viii. 70 (1873). 
