122 Rhodora (Jury 
repens L., Gaultheria procumbens L. anf Gaylussacia dumosa (Andr.) 
T. &G. (as var. Bigeloviana Fernald), which southward are character- 
istic of dry silicious habitats (pine or oak barrens and dry woods, 
ete.) but which northward, especially in the dominantly calcareous 
areas bordering the Gulf of St. Lawrence, are apparently able to exist, 
at least are found only in the acid bogs and black spruce swamps. 
In Newfoundland, P. rotundifolia, var. arenaria likewise has in- 
terchangeable habitats, sometimes occuring in open sandy or gravelly 
thickets or on pond-shores, but oftenest in wet sphagnous bogs or 
spruce swamps. In the latter habitat the branches of the subter- 
ranean stems become greatly elongated and their coriaceous, brown, 
oblong, blunt or mucronate bracts consequently remote; in the drier 
habitats the caudex is short and the bracts more crowded as in most 
European specimens. Var. arenaria, although not definitely known 
from the American continent, is the representative of the species in 
Greenland; and, now well known from Newfoundland, it is to be 
sought on the Labrador Peninsula and elsewhere in our northern 
regions. 
The two American varieties of P. rotundifolia may be distinguished 
as follows: 
P. ROTUNDIFOLIA L., var. ARENARIA Mert. & Koch in Roehling, FI. 
Deutschl. iii. 103 (1831); Koch, Syn. 478 (1838); Lange, Consp. FI. 
Groenl. 84 (1880); Andres, Oesterr. Bot. Zeitschr. lxiv. 239 (1914). 
P. intermedia Schleich. Cat. Pl. Helv. ed. 3, 23 (1815). P. maritima 
Kenyon, Phytol. ii. 727 (1847). Thelaia intermedia (Schleich.) Alef., 
Linnaea, xxviii. 65 (1856).—Leaf-blades 1.8-5 em. long, 1.5-4 em. 
broad: racemes 3-13-flowered, in anthesis 2-9 cm. long: lower 
braets 1-2 mm. broad: calyx 5-7 mm. broad, its firm lance-oblong 
to oblong-obovate lobes 1.6-3 mm. long: petals 5-7 mm. long, 4-6 mm. 
broad: anthers 2-2.7 mm. long.—Northern and middle Europe 
and Asia; Greenland and Newfoundland. The following New- 
FOUNDLAND specimens belong here: sphagnum swamp, Manuel’s, 
August 8, 1894, Robinson & Schrenk; cool thicket, Western Bay, 
Conception Bay, August 21, 1914, G. S. Torrey, no. 94; boggy places 
on hill southwest of Tilt Cove, August 21, 1911, Fernald, Wiegand & 
Darlington, no. 6001; open bogs among the hills, Grand Falls, July 
26, 1911, Fernald, Wiegand, Bartram & Darlington, no. 6000; wet 
boggy woods, Millerton Junction, Fernald, Wiegand & Darlington, 
no. 5998; gravelly beach, Middle Birchy Pond, July 11, 1910, Fer- 
nald & Wiegand, no. 3812. 
Var. americana (Sweet), n. comb. P. americana Sweet, Hort. 
Brit. ed. 2, 341 (1830); Fernald, Rropona, vi. 201 (1904); Andres, 
