1917] Fernald,— Variations of Polygonum pensylvanicum 71 
‘Mr. Bicknell to be the prevailing form on Nantucket, where, as on 
Block Island, it is characteristic of sandy pond-shores near the sea, 
has been beautifully described by Mr. Bicknell, who, apparently from 
his disinclination to recognize varieties, left the plant without a dis- 
tinguishing name. Mr. Bicknell’s description is so accurate and so 
clearly applies to the plant of Block Island as well as of Nantucket 
that it is here quoted: 
“ PERSICARIA PENNSYLVANICA (L.) Small. The common erect form 
of this plant with lanceolate tapering leaves and cylindric spikes of 
rather pale pink ovoid-oblong flowers is uncommon on Nantucket 
and was met with only twice — at Wauwinet and in Quaise. The 
prevailing form is mostly prostrate or ascending and is confined 
almost exclusively to the sandy shores of ponds near the ocean on the 
south and east sides of the island. In its extreme development it is 
notably different from the erect narrow-spiked form but appears to 
be a state of the latter, rather than an intrinsically diverse plant. By 
comparison it is characterized by short-oblong or even subglobose 
more densely flowered spikes, usually of a bright rose-color or carmine- 
red, although sometimes pale, the flowers shorter and almost orbicular 
in outline, the achenes rather larger, thicker, and more broadly orbicu- 
lar, often more abruptly narrowed to a rather shorter style; the leaves 
are often marked above by a dark chevron and are commonly shorter, 
broader and less attenuate to a blunt or rounded apex and on shorter 
petioles, the upper most often sessile. The plant is often firmly pros- 
trate and is sometimes very small, stems bearing mature spikes being 
sometimes only 1 dm. long.” ! 
So far as the writer is able to determine this characteristic plant is 
known only from the two outer islands, Nantucket and Block Island, 
although it is naturally to be expected on the shores of Martha’s Vine- 
yard, the Buzzard’s Bay region and Long Island. In its distribution 
it is coincident with many other extreme variations and localized 
species, and it seems to the writer well worthy varietal recognition. 
We have, then, in eastern North America three well pronounced 
geographic variations passing as Polygonum pensylvanicum and the 
question naturally arises as to which was the plant of Linnaeus. In 
this particular case happily Linnaeus left no question, for he well de- 
scribes the coastal plain plant with strigose or scabrous lower leaf-sur- 
faces as having “ Folia lanceolata, acuminata, subtus ad modum scabra.” ? 
These notes, which were originally based upon the material in the 
1 Bicknell, Bull. Torr. Bot. Club, xxxvi. 452 (1909). 
2 L. Sp. Pl. i. 362 (1753). 
