- 50 — 
forms: — (1). leaves 1.2X0. 8 mm, imbricate or patent at the tip, lan- 
ceolate, long acuminate, revolute to apex, marginal teeth in pairs, costa 
slender, long excurrent, with dentate, piliform point; areolation rectangular, 
papillae at the lower angles; (2), leaves plane, obtuse, crenulate, the costa 
ceasing below the apex, or percurrent, or somewhat excurrent. Perigonial ' 
leaves broadly lanceolate, gradually acuminate. — {Essai, 410.) 
Range: — Alaska, Canada and Greenland, south to California, Col- 
orado and Minnesota, usually at considerable altitudes. 
van BOREALIS. (Hag.) Loeske, Hedw. 45 : 206. (1906). 
Ph. fontana var. borealis Hagen, Kgl. Norsk. Vidensk. Selsk. 
1888. 
Stem but little branched; leaves dimorphous; the upper roundish- 
oval, crenulate at apex, costa ceasing below apex or sometimes per- 
current; the lower leaves oval lanceolate, areolation lax, especially at 
the base. — {Essai. 412.) Range: — Alaska, Montana. 
var. COMPACTA (Schimp.) Dismier, Essai. 413. (1908). 
Ph. fontana var. compacta Schimp. Syn. Muse. Ed. 2: 220. 
(1876). 
, Tufts compact, closely interwoven with radicles, stems very long 
(l5 cm.). Range: — Greenland, Labrador, British Columbia. 
var. HETEROPHYLLA Dismier. 
' Varies from the type in that the stems end in very slender innova- 
tions which have the leaves distant, and wholly different in form and 
structure from those of the main stems. Range: — Selkirk Mts. 
A boreal or alpine species which, while readily distinguished when 
in normal condition, approaches Ph. fontana when growing at lower 
altitudes. The shape and margin of the leaves, and the slender, 
piliform, excurrent costa give it a very distinct facies under the 
microscope. 
All specimens of Ph. acutiflora Kindb., Hedw. 35 : 67. (1896),* 
examined were referable either to Ph. fontana or to the present species . 
10. Philonotis CAESPITOSA Wils., in sched. Muse. Brit. No. 278. 
Braithw., Br. Moss El. 2 : 210. t.77. E. (1893). 
Tufts more or less dense, stems 5-7 cm. high, simple or branched, 
subverticillate ; stem leaves, secund, oval, lanceolate-acuminate, falcate, 
wholly plane, without plicae, margin denticulate, the teeth simple above and 
in pairs below: papillae over the upper ends of the upper cells, but in 
the lower ones over the basal angles. Perigonial leaves very large, 
concave, acute, rarely obtuse, with the weak costa vanishing at the apex, 
or slightly excurrent. — {Essai, 397.) 
M. Dismier refers to this by error as Ph. acutifolia, Kindb. 
