A KEY TO TIIE BRITISH SPHAGKA 
311 
II. St. Is. with wide base; Is. entire. 
a. St. Is. lingulate. 
# St. Is. fibrillose; outer side of br. 1. 
with large non-bordered pores . S. rubellum Wils. 
## St. Is. without fibrils; outer side of 
br. 1. with small bordered pores. 
Br. Is. imbricate . S. fuscum Klinggr. 
Br. Is. erecto-patent . S. Warnst orjii Buss. 
b. St. Is. triangular to triangular-lingu- 
late. 
* Br. Is. minute, under 1 mm. S. subtile Warnst. 
## Br. Is. over 1 mm. 
f St. Is. fibrillose. 
St. cortex with pores . S. tenerum Sail. 
St. cortex without pores . S. acutifolium Ehrh. 
ft St. Is. without fibrils. 
Wood cylinder never red; st. 
cortex porose . S. quinquefarium Warnst. 
Wood cylinder reddish to dark 
purple; St. cortex rarely with 
pores . 
Group Bigiha. 
Cblor. cells completely enclosed ; st. Is. minute. 
Group Sqtjarrosa. 
A. Stem cortex 2-3-layered. 
B. Stem cortex 3-4-layared. 
Group Cuspidata. 
A. Branch leaves narrow or widelv lanceolate. 
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I. Chlor. cells, of the br. Is. trapezoid. 
a. St. Is. equilateral, to isosceles, triangular. 
St. cortex clearly differentiated. 
St. Is. obtuse. 
St. is. acuminate. 
Br. Is. serrate.. 
Br. Is. entire . 
St. cortex not clearly differentiated... 
b. St. Is. with the apex rounded and more 
or less lacerato-bifid . 
II. Cblor. cells of the br. Is. triangular. 
a. Chlor. cells not reaching the surface of 
the 1. 
St. Is. with narrow base . S. Lindbergii Schimp, 
St. Is. wider at the base. 
St. Is. obtuse. 
St. Is. without fibrils . S. obtusum Warnst. 
St. Is. fibrillose . S. balticum Buss. 
St. Is. acuminate. 
S. plumulosum Boll. 
S. compact-urn DC. 
S. squarrosum Pers. 
iS. teres Angstr. 
S. Dusenii C. Jens. 
S. serratum Aust. 
S. cuspidatum Ehrh. 
S.fallax Klinggr. 
S. rip avium Angstr. 
