i6 The Ottawa Naturalist. [April 



on well developed individuals : rhizoids yellowish to reddish : 

 leaves imbricated, obliquely inserted, widely spreading, very 

 broadly orbicular, 1.9 mm. long, 3 mm. wide, antical lobe 

 often a little smaller than the postical, broadly ovate, slightly 

 decurrent, antical margin rounded, apex rounded to subacute, 

 usually terminating in an apiculum consisting' of a row of 

 from one to four cells ; sinus (in explanate leaves) varying 

 from obtuse to broadly and shallowly lunulate or truncate ; 

 postical lobe orbicular, postical margin rounded, sometimes 

 subcordate at base, more rarely short-decurrent, apex 

 rounded to obtuse, sometimes apiculate ; margin repand, in- 

 distinctly crenulate from projecting colls, sometimes bearing 

 one or two short teeth at about the middle of the antical lobe 

 or near the postical base ; leaf-cells at the edge of leaf 

 0.025 X 0.021 mm., in the middle isodiametric, averaging 0.031 

 mm., slightly elongated at the base, trigones slightly bulging 

 into cell-cavities ; verrucuiae of cuticle densely crowded, oval or 

 circular in outline : underleaves with lanceolate or subulate 

 long-attenuate divisions, each i .4 mm. long, o. 17 mm. wide; 

 marginal cilia six to fifteen on each division, mostly two to 

 twenty cells long and one to five cells wide at base ; cells of 

 underleaf with more uniformly thickened walls than in leaf, 

 trigones indistinct, cuticle verruculose : inflorescence dioicous; 

 $ bracts alternate in about three pairs, the innermost quad- 

 rate, 2 mm. long, with sharper lobes than in the leaves, both 

 antical and postical commonly apiculate, marginal teeth more 

 usual than on ordinary leaves: innermost bracteole often torn 

 in two and carried down by the developing perigynium ; 

 perianth ovate in outline, 2 7 mm. long, 1.4 mm. in diameter, 

 one cell thick, irregularly lobed at the contracted mouth, the 

 lobes short-ciliate on their margins with cilia from one to four 

 cells long and one cell broad throughout ; perigynium cylin- 

 drical, hollow, roanded at the apex, 3 mm. long, 1.4 mm. in 

 diameter, the wall about ten cells thick (0.25 mm.), some- 

 what thinner toward junction with perianth : calyptra about 

 five cells thick (0.15 mm.) over capsule, thicker in lower part; 

 archegonia usually ten to sixteen : antheridia few in the axil 

 of each $ bract. {Plate I.) 



