[From the BuLLETIN oF THE TorREY BoTANICAL Crus, 47: 367-395, 14 O 1920.] 
Calymperaceae of North America 
R. S. WILLIAMS 
(WITH PLATES I 5-17) 
The next part of the North American Flora relating to mosses 
will comprise the families Fissidentaceae and Calymperaceae. 
The second of these families includes only two genera, Syrrhopodon 
and Calymperes. The results obtained from the study of this 
group are here offered in advance, partly to allow the illustrations 
of cross-sections of the leaves to be issued with the descriptions. 
SYRRHOPODON Schwaegr. Suppl. 2?: 110. 1824 
Dioicous or rarely autoicous.. Growing in mostly compact 
cushions of pale green to greenish brown color with more or less 
radiculose, branching stems from a few millimeters to 6-8 cm. 
high. Leaves with mostly imbricate, often conspicuously white 
base, mostly narrowed upward to a point varying from straight 
to crispate and from lanceolate to lingulate or ligulate, with acute 
or rounded, mostly denticulate apex and having a distinct border 
(except in S. martinicensts) either much thickened or of hyaline 
or yellowish cells. Costa stout, from nearly percurrent to excur- 
rent, often papillose or spiny on one or both sides, in cross-section 
showing one row of guide-cells with rarely a few accessory guide- 
cells, stereid bands above and below them and outer cells mostly 
differentiated. Leaf-cells throughout upper part of leaf chloro- 
phyllose and roundish or oval to quadratic, rarely smooth, mostly 
papillose or mamillose on one or both sides; cells of the erect base 
mostly hyaline (the cancellinae), square to. linear, changing 
abruptly into the green cells of upper part of leaf. Perichaetial 
leaves usually smaller than the stem-leaves. Seta erect, elongate 
367 
