1920] Fernald & Wiegand,—Cerastiums of Section Orthodon 171 
Basal leafy branches and offshoots herbaceous, 
with few axillary tufts of oblong leaves: 
petals about equalling to !$ longer than the 
sepals, with ascending lobes and pubescent 
or ciliate claw. 
Sepals 7-10 mm. long: capsule 1.7-2.3 cm. 
long: seed 1.3-1.8 mm. in diameter . 7. C. unalaschkense. 
Sepals 4-7 mm. long: capsule 7-11 mm. long: 
seed 0.5-0.7 mm. in diameter . . . 8. C. vulgatum. 
Basal branches and offshoots becoming dry and 
marcescent, bearing conspicuous axillary 
fascicles or leafy tufts: petals 2-3 times as 
long as the sepals; the broad lobes spreading 
during anthesis; the claw glabrous . . 9. C. arvense. 
1. C. ALPINUM L. Densely or loosely matted; the flowering 
stems weak, 0.1-3 dm. long, hirsute, glandular or lanate; the basal 
offshoots lanate or at least their leaves with the pubescence entang- 
ling at tip: leaves of the season oval, oblong, lanceolate or narrowly 
ovate, 0.5-2 cm. long; bracts similar or the uppermost slightly 
scarious-margined: flowers 1-6: pedicels straight, strongly ascend- 
ing, finally spreading, much longer than the calyx, in fruit becoming 
(except in extremely dwarfed forms) 1.5-5 em. long: sepals ovate- 
lanceolate, in anthesis 5.5-9, in fruit 6-10 mm. long: petals cuneate- 
obovate, about twice as long as the calyx; the 2 oblong lobes ascend- 
ing: capsule nearly straight, ca cm. long: seeds tuberculate, 
1-1.3 mm. in diameter.—Sp. PI. 438 (1753).—A_ very variable 
arctic-alpine species, represented with us by the following varieties. 
Var. LEGITIMUM Lindblom. Summit of stem, pedicels and calyx 
with straight short glandless pubescence.—Physiogrüph. Sallsk. 
Tidskr. i. 336 (1837)—reprinted in part in Flora (1841) 591. C. 
alpinum L. sensu stricto. Centunculus alpinus (L.) Scop. Fl. Carn. 
ed. 2, i. 321 (1772). Stellaria alpina (L.) S. F. Gray, Nat. Arr. Brit. 
Pl. ii. 660 (1821). C. mutabile alpinum (L.) Gren. Mém. Soc. Émul. 
DL 71 (1841). C. alpinum, var. hirsutum Fenzl in Ledeb. FI. 
Ross. AM (1842).—Arctie regions, south on granitic, schistose or 
icu rocks and gravel to Labrador, Ungava and Keewatin. "The 
more southerly stations are as follows. LABRADOR: Kangalaksiorvik 
Bay, September 1-10, 1908, Owen Bryant; 20 miles north of Nachvak, 
August 28, 1908, H. S. Forbes; near Hopedale, Knuth; Indian Har- 
bor, Hamilton Inlet, August 2, 1891, Bowdoin College Exped., no. 
175; St. Francis Harbor, July 20, 1891, Bowdoin College Exped., no. 
112; Dumpling Harbor, July 7, 1864, B. P. Mann. Uneava: Port 
Burwell, Hudson Straits, July 18, 1910, J. M. Macoun, no. 79,081; 
Digges Island, September 16, 1884, H. Bell; Great Whale River, 
Hudson Bay, July 5, 1899, A. P. Low, no. 63,164, in part. KEE- 
WATIN: Churchill, August 15, 1879, R. Bell, no. 4216, August 18, 
191C, J. M. Macoun, no. 79,082; Cape Henrietta Maria, August 18, 
1904, Spreadborough, no. 62,328. 
Forma PULVINATA Simmons, Vasc. Pl. Ellesmerel. 122 (1906).— 
A condensed arctic form with succulent glabrous leaves. 
