18 
the lower sometimes short-stalked; fruit ovoid, dull, obtusely angled, 
often slightly contracted below the middle, with a short beak; style 
short; stigma oval, oblique, at the base distinctly bounded. 
Am.: West Greenl. 64° 32’ (1). 
Geogr. area: Northern North America, Iceland, Europe, Northern 
Siberia. 
35. §. submuticum (Hartm.) Neum. 
S. hyperboreum Laest., Lge. Consp. Fl. Groenl. p.116; Roseny. Till. 
p. 709; Scheutz, Pl. vase. Jeniss. p. 162; Fl. D. t. 2792. 
Leaves long, narrow, 2—3 mm. broad, floating, slightly convex 
below; male head 1; female heads 1—4, the lower stalked and free 
from the angles of the sheaths; stigma sessile or very short-stalked, 
at the base not distinctly bounded, fruit ovoid, dull, obtusely angled, 
without beak. 
Am.: West Greenl. 60°—68° 37’ (!), As.: Mouth of the Yenissei. 
Geogr. area: Northern Canada, Iceland, Northern Scandinavia 
and Finland, Northern Siberia. 
36. S. affine Schnitzl. 
Macoun, Catal. IV p. 71; S. natans, Ledeb. Fl. Ross. [IV p.5; Rothr. 
Fl. of Alaska, p. 455. Fl. D. Suppl. t. 171. 
Leaves very long, narrow, 3—5 mm. broad, floating, convex 
below; stem-leaves with inflated sheaths; male heads 1—5, clu- 
stered; female heads 2—4; the lower long stalked and free from 
the angles of the sheaths; fruit fusiform, more or less contracted 
below the middle, shining, with rather long beak; style rather long; 
stigma linear-lanceolate, at the base distinctly bounded and slightly 
notched. 
Am.: Kotzebue Sound, West Greenl. c. 61° (1). 
Geogr. area: Unalashka, Northern North America, Iceland, Feerées, 
North, West and Central Europe, Siberia. 

Order IX. POTAMOGETONACEAE Aschs. (By C. H. OSTENFELD). 
Flowers perfect, perianth-segments 4, stamens 4, carpels 4; spike cylindrical 
Potamogeton. 
Flowers monoecious, perianth 0, stamens 1, carpel 1, spadix flat. . . Zostera. 
i. ZOSTERA TE: 
Sep Laamaninamse 
Lge. Consp. Fl. Groenl. p.117 and p.282; Kjellm., Vest-Eskim. Land, 
p- 53; Fl. D. t.15 and t. 1501. 
Rhizome creeping; leaves ribbon-shaped with 3—5 nerves, obtuse, 
often with a little kerf at the apex; flowers arranged in two rows on 
