231 
Leaves usually oval or obovate, obtuse, four to six in a 
whorl. 2. H. tetraphylla. 
Very small Arctic plants, with linear, mucronate leaves, 
five to six in a whorl. 3. H. montana. 
1, Af algaris,. 1. Sp. Ply 4: (1753). 
Springing from a perennial rootstock, with annual, simple, 
erect stems and whorls of six to twelve or more one-nerved linear 
or lanceolate leaves which are more or less decayed (sphacelated) 
at the tips, and 10-20 mm. long by 1-3 mm. broad. Stamens 
with short, thick filaments and comparatively large two-celled 
anthers, which dehisce laterally. Fruit oval, or somewhat four- 
sided, hollow in the interior, 2 or 3 mm. long, stigmas persistent. 
Common in Arctic America and Canada, It occurs also in Moose- 
head Lake, Maine (Porter), west to Oregon, and thence to 
California (Parish) and New Mexico. Mr. Safford sends it from 
the Straits of Magellan, and it is common in Europe and Cen- 
tral Asia, 
Var. fluviatilis. Wart. Scand. Fl. 150 (1849). 
A very luxuriant, deep water form, entirely or nearly sub- 
merged, Leaves 6 cm. long by 2-3 mm. wide, grass-like, nu- 
merous, in closely crowded whorls. Lake Winipeg (Macoun), 
Keweenaw Peninsula, Michigan (Robbins) and Oregon aide 
Not uncommon in Sweden. 
2. H. tetraphylla. L. f. Supp. 81 (1781). 
H. lanceolata. Retz. Obs. Fasc. 3, 7, t. 1 (1783). 
H. maritima. Hell. Dis. Hipp. in Ust. Opusc. I. I. t. 
I (1786). 
This is usually a smaller plant than the preceding, rarely at- 
taining a height of over 20 cm. Sometimes, however, as in 
Labrador specimens, twice that height. The leaves are in whorls 
of fours or sixes, oval, obovate or occasionally oblanceolate, but 
little, if at all, decayed at the tips, and often feather- veined. Fruit 
less than 2 mm. in length. It ranges from Alaska and Hudson’s 
Bay to the Gulf of St. Lawrence, and from Sweden to Siberia. 
3. H. montana. Ledeb. in Reich. Bot. 1. 71 (1827). 
This diminutive northern plant, as Torrey and Gray remark, 
(Fl. N. A. p. 531), looks very much like a small Gatium. Stems 
3-6 cm. high. Leaves one-nerved, linear, mucronate, in fives 
