a 
NortH AMERICAN SPECIES OF LESKEA 465 
Leaves ovate, subacute to obtuse, less than twice as long as wide. 
Leaves symmetric, biplicate, margins often revolute. L. gractlescens, 
Leaves asymmetric, not plicate, margins plane. L. obscura. 
HETEROLESKEA : leaves smooth or nearly so, costate or ecostate, median cells longer 
than wide ; peristomial teeth erect when dry. 
Leaves denticulate, ecostate. L. denticulata. 
Leaves entire or nearly so, costate ; 
Acumen longer than body ; 
Costa subpercurrent. L, nervosa. 
Costa short. L. Williamsi. 
Acumen shorter than body ; : 
Costa short, bifid. 
Leaves smooth. L. tectorum. 
Leaves subpapillose. L, cyrtophylla. 
1. LESKEA poLycarPaA Ehrh. Dec. Crypt. 96. 1788. 
Fypnum repens trichodes arboreum medium capitulis erectis Dill. 
Cat. Giss. 216. 1718. 
Fypnum trichodes, capsulis oblongis, in setis brevioribus Dill. 
Hist. Musc. 331. 1741. 
Hypnum medium Dicks. Crypt. 2: 12. 1790. 
flypnum polycarpon Hoffm. Deutsch. Fl. 2: 67. 1796. 
Leskea paludosa var. polycarpa Hartm. Skand. FI. Ed. 5, 337. 
1849. 
In spreading tufts or loose mats, pale green, sometimes dirty 
dark green, passing to yellowish green or reddish brown ; stems 
prostrate, 2-4 cm. long, radiculose, subpinnately branched ; cen- 
tral strand small, distinct: paraphyllia few, linear-lanceolate : 
stem-leaves * loosely appressed when dry, erect-spreading when 
moist, 0.8—1.2 mm. long, 0.35—0.45 mm. wide, from a subcordate, 
slightly decurrent, ovate or oblong-ovate base, lanceolate, grad- 
ually acute to abruptly acuminate, more or less secund and 
obliquely pointed, biplicate, entire, one or both basal margins 
usually recurved, costa disappearing below apex ; branch-leaves 
smaller, often obtuse or blunt-pointed ; median cells of stem-leaves 
roundish quadrate-hexagonal, 7-8 » wide, with one or two small 
papillae on each surface ; basal quadrate-oblong ; alar quadrate or 
transversely oval : monoicous: perichetial bracts erect, oblong-lance- 
olate, acuminate, inner subvaginant, plicate-striate, lightly costate ; 
pedicel about 1 cm. long, smooth; capsule erect, straight or 
* When stem-leaves are referred to those from the middle third of the stem are 
meant and when branch-leaves those from the middle third of a branch. In most 
species of this genus a considerable difference will be found between the upper and 
lower leaves. The plicae of the leaves are seen to the best advantage before pressure: 
is applied. 
