180 American Midland Naturalist Monograph No. 6 



Family 25. Climaceae 



Dioicous; flowers on secondary stems and at base of branches; gregarious, 

 large and stately, growing in swamps: stems rhizome-Iilce, subterranean, radicu- 

 lose, with smooth, branched, reddish-brown rhizoids, secondary shoots 3- to 

 several-angled, erect, with more or less tree-like branching, with central strand; 

 branches leafy, cylindric, simple, pinnate or bi-pinnate; paraphyllia numerous; 

 leaves dimorphous, the rhizome and lower part of stem having scale-like and 

 appressed colored leaves, the upper stem and branches having green leaves; 

 leaves plicate; costa simple, homogeneous, ending below the apex, at the base 

 widened by two or three layers of laminal cells; leaf-cells smooth, upwardly 

 narrow-rhombic, downwards linear, the basal orange, the alar hyaline, lax, thin- 

 walled and forming a distinct group; perichaetial leaves numerous, long and 

 slender; sporogonia often aggregated: seta long, erect, stiff, sinistrorse; capsule 

 erect and symmetric in Cltmacium; exannulate; peristome double with the parts 

 of equal length; teeth confluent at base, reddish-brown, articulate, papillose, 

 ours not transversely striate, the lamellae numerous; inner peristome yellow, 

 papillose, with more or less of a basal membrane, the segments carinate, more 

 or less gaping along the keel, cilia none; spores medium size; operculum ros- 

 trate from a convex base; calyptra cucullate. 



Two genera: Pleuroz'opsis, with one species, in our regions bordering the 

 North Pacific, and the following: 



1. Cltmacium Weber and Mohr 



Mostly as characterized in the description of the family: branches simple, 

 or sometimes almost pinnate, unequal, attenuate; branch-leaves lance-ligulate 

 from a decurrent, auricled base, bluntly to sharply acute, sharply serrate above; 

 inner perichaetial leaves abruptly acuminate, entire, short-costate; costa of the 

 leaves strong, ending below the apex, dorsally toothed above: seta 15-45 mm 

 long, stiff, castaneous; capsule erect, symmetric, almost cylindric, castaneous; 

 teeth lance-linear, acuminate, with a dark red border, with low papillose dorsal, 

 plates, and with closely placed trabeculae; inner peristome orange, vertically 

 striate-papillose, segments linear, carinately gaping, finally divided; spores .015- 

 .020 mm, rusty, warty; calyptra long, narrow, enclosing whole capsule, cleft 

 on one side to apex, sometimes twisted. 



A widely distributed genus of about 5 species: 3 occurring in North 

 America and extending into our region. 



Key to the Species 



'i. Plants of dendroid habit B 



A. Plants not distinctly dendroid, median leaf-cells about 2-3:1 3. C Kindbergii 



B. Auricles not prominent; median leaf-cells 8-10:1 1. C. dendroides 



B. Auricles broad, median leaf-cells about 5-7:1 2. C. americamim 



1. Climacium dendroides [Linnaeus] Weber and Mohr 

 (Hypnum dendroides Linnaeus; Leskea dendroides Hedwig) 



Dendroidal, robust, bright or yellowish-green; the primary stems under- 

 ground, creeping, divided; the secondary stems rising to a height of sometimes 



