Polygonum. POLYGON ACE. 247 
alien species, such as the vicinity of ports where a large 
trade in American grain is carried on, or the neighbourhood 
of mills where this grain is often handled in immense 
quantities, rather than in this isolated bog in Kerry. The 
most probable explanation is that the plant was introduced 
here about the time of the terrible famine of 1847, when 
American grain was distributed to the starving peasantry 
in this part of Kerry as elsewhere in the south and west 
of Ireland. The present restricted range of the plant outside 
America is, however, impossible to account for. The hard 
nuts and the prickly clinging character of this Polygonum 
would appear to lend themselves readily to its dispersion, 
but during the nineteen years that it has now (1907) been 
under observation, very little difference has been noted 
either in its quantity or in the area it occupies, except that 
in 1904 the plant was more abundant along the course of the 
stream than formerly ; these river-bed stations, however, 
vary no doubt from year to year with a dry or wet season. 
The fact that all the five Irish members of the North 
American group grow within a radius of less than twenty 
miles of this spot—one of them, Juncus tenuis, occurrmg 
abundantly within a few hundred yards of it—renders 
caution additionally necessary when enquiring into the 
standing of any newly discovered American plant within 
this area. The very restricted nature of its solitary station 
outside of America, would alone render it an unlikely native 
of Kerry and it is, moreover, worthy of note that the Poly- 
gonum is an annual, while the other members of the Irish 
American group are perennials with the exception of the 
aquatic plant Naias flexilis. And tempting as it undoubtedly 
is to make Polygonum sagitiatum an addition to this most 
interesting little group, it must be regarded rather as an 
alien in some way accidentally introduced many years ago 
and now fully established in a wild locality.* 
[P. Bisrorta Linn. Snakeweed.—VII. “In Sir Thomas 
Denny’s park near Tralee ” (Dr. Smith) Hist. of Kerry, 1756, 
* Mr. G. C. Druce when visiting the locality in 1906 was given the follow- 
ing explanation of the presence of this Polygonum by a peasant. About 
fifty years ago the owner of a small mill which formerly existed on this stream, 
ground there some Indian corn, the cargo of a boat wrecked on the neig’- 
bouring shore. According to this informant the Polygonum appeared in 
the neighbourhood the following year and thence spread to the sites where 
it is now found—vide Irish Nat. 1907, p. 150. The master of the local 
schools, a resident in the district all his life and now an old man, informed 
