1919] Fernald,— Lomatogonium 195 
S. pusilla Pursh, Fl. Am. Sept. i. 101 (1814). ZL. sulcatum (Rottb.) 
Reichenb. ex Kostel. All. Med.-Pharm. Fl. iii. 1048 (1834).  Narketis 
rotata (L.) Raf. Fl. Tell. iii. 26 (1836). N. hyperborea Raf. 1. c. (1836). 
Pleurogyna sulcata (Rottb.) G. Don, Gen. Syst. iv. 188 (1837).  Pleuro- 
gyne rotata (L.) Griseb. Gen. et Sp. Gent. 309 (1839). P. Purshit 
Steud. Nom. ed. 2, ii. 355 (1841). P. carinthiaca, var. pusilla (Pursh) 
Gray, Syn. Fl. N. A. ii. pt. 1, 124 (1878). P. fontana A. Nels. Proc. 
Biol. Soc. Wash. xvii. 177 (1904). 
The plant of eastern America,— southwestern Greenland, southern 
Labrador, Newfoundland and eastern Quebec!— is extremely vari- 
able. Some individuals beautifully match Gmelin’s plate? of the 
Siberian plant originally taken up by Linnaeus as Swertia rotata, a plant 
with lance-attenuate leaves and calyx-segments. Others, the major- 
ity, have the blunter, more oblong-lanceolate leaves of Pleurogyne 
rotata, var. americana Griseb;? while more extreme individuals have 
the leaves and sometimes the calyx-segments oval and quite obtuse. 
These extremes, often occurring in the same colonies and connected by 
abundant transitional specimens, are not varietally distinct but at 
most can be recognized merely as somewhat striking forms. 
Neither does it seem possible to distinguish clearly Pleurogyne 
rotata, var. tenuifolia Griseb.,' which is apparently identical with P. 
fontana A. Nelson? The latter plant is usually taller and more 
fastigiate than the maritime individuals and it has more slender 
leaves and calyx-segments. Nelson argues, furthermore, that it can- 
not be P. rotata because “That species seems to skirt the northern 
boundary of the continent, from Labrador and Greenland to Alaska," 
while * P. fontana seems to be closely circumscribed, being probably 
confined to north central Colorado and the adajcent border of Wyo- 
ming.” He further says that “the most obvious difference is the 
different arrangement of the leaves; P. fontana being relatively naked 
below while in P. rotata the leaves are crowded or even rosulate at base." 
Now, looking into these characters in the order of their importance, 
we find that of 42 individuals seen from Colorado and Wyoming 14 
1 Pursh's Sùwerlia pusilla was said by him to come from *'the alpine regions of the White-hills 
of New Hampshire... . In the Banksian Museum are specimens from Labrador, in every respect 
agreeing with the New Hampshire plant." But no material of Pursh's plant from New Hamp- 
shire is known nor is it probable that the plant occurs southwest of the lower St. Lawrence. 
There it is confined to brackish sands or springy borders of saline marshes. 
2 Gmel. Fl. Sib. iv. t. liii, fig. 1 (1769). 
. 3 Griseb. Gen. et Sp. Gent. 309 (1839). 
4 Griseb. l. c. (1839). 
5 A. Nelson, Proc. Biol. Soc. Wash. xvii. 177 (1904). 
