308 FRYE 
5. Marginal cells of lamellz notched in cross section. 
6. Capsule about as 1:14~-14, sharply 4—-angled. 
7. Plants 5>45°cm: hich.) ..255.6en sree 5. P. commune. 
4. Leaf point red, smooth, 4 mm. or shorter. 
5. Marginal cells of lamellze oval or flattened in cross section, 
not thickened, width to height about as 2: 1. 
6. Capsule unknown. 
7. blants' 4—Sem. high’) 5c eee 4. P. inconstans. 
1. Leaf margin serrate from the middle up. 
2. Margin plane below, erect or somewhat incurved above. 
3. Leaves sharply pointed, the point composed mostly of the excur- 
rent vein. 
4. Leaf point red, dentate, 1 mm. long or shorter. 
5. Marginal cells of lamellae notched in cross section. 
6. Capsule unknown. 
Ge leleevone seo) (oon jeikdolana ones, een o- 6. P. jensenn. 
1. Leaf margin entire. 
2. Margin plane or erect. 
3. Leaves sharply pointed, the vein excurrent as an arista. 
4. Arista red, smooth, 1 mm. long or shorter. 
5. Marginal cells of lamella notched in cross section. 
6. Capsule unknown. 
7 lAMts i5n0 Cla WIC yas Lacan eee 7. P. yukonense. 
2. Margin plainly incurved. 
3. Leaves blunt, cucullate. 
4. Arista or sharp point none. 
5. Marginal cells of lamella ovate, thickened, width to height 
about as I : 2. 
6. Capsule about as 1 :14, bluntly 6-angled. 
ie Jellevanis Does) (eines [NEI 4 4b oe 4 ees ae 8 P. sexangutare. 
3. Leaves sharply pointed, the vein excurrent as an arista. 
4. Arista red, rarely somewhat colorless at tip, rough, 4-14 mm. 
long. 
5. Marginal cells of lamelle ovate or flask-shaped. 
6. Capsule as 1 : 14-13, sharply 4- angled, 3-5 mm. long. 
7. Plants 2-10 cm. high. 
b. Stem without dense covering of rhizoids. 
g. P. juniperinum. 
6. Capsule about as 1:14, sharply 4-angled, 2-3mm. long. 
7. Stems mostly with dense covering of rhizoids. 
ro. P. strictum. 
