144 American Midland Naturalist Monograph No. 6 



McKean, Mercer, and Westmoreland. Specimen figured: Houston Junction, Mercer Co., 

 July 12, 1902. J.A.S. 



12. Mnium cinclidioides (Blytt) Huebener 

 Plate XXVII 



Large, loosely cespitose, bright green, becoming dark when old: stems rigid, 

 under exceptional conditions reaching 15 or 20 cm or more, our specimens 

 sterile and about 4-8 cm high, stems dark brownish; leaves remote, thin, large, 

 the lower ones ovate to oblong and not at all decurrent, the upper rosulate 

 from a narrow base, widely oblong-lingulate or obovate, rounded and obtuse 

 v/ith a minute apiculus, more or less undulate, up to 7 or 8 mm long and 4 

 mm wide in our specimens, margin non-bordered, entire with the exception of 

 occasionally projecting marginal cells; costa ending considerably below the 

 apex; leaf-cells rhomboid-hexagonal, arranged in series radiating from the costa, 

 the marginal gradually becoming linear and parallel to the margin, all rather 

 thin-walled, chlorophyllose, the larj^est up to about .030 x .100 or .110 mm: 

 seta long, rather slender; capsule abruptly pendent, shortly oval; lid conic- 

 apiculate; peristome brownish: dioicous: mature in late spring or early summer. 



In bogs, pools, and swamps in the cooler parts of Europe, Asia, and North 

 America down in glaciated regions to New Jersey and Pennsylvania and south- 

 ward along the upland plateaus and mountains; generally sterile. 



Butler Co.: Wet bank of brook, north of Dougherty's Mills. July 28, 1935. Sid- 

 ney K. Eastwood. Crawford Co.: In Pymatuning Swamp, Linesville, June 12, 1905. 

 O.E.J, (figured). Sterile. Elk Co.: Wet wood in swamp. Sept. 2, 1935. Sidney K. 

 Eastwood. McKean Co.: Sphagnum Swamp, West Branch, July 5, 1896, and July 22, 

 1894. D.A.B. Sterile. Somerset Co.: Cranberry Glade Run, Laurel Hill mt. Swampy 

 woods. Elev. 2300 i ft. C.M.B. June 28, 1942. Vena::co Co.: Tarl;iln Run. near Van. 

 John Wurdack. Aug. 29, 1936. 



Family 16. AuLACOMrnACEAE 



Dioicous, rarely autoicous: robust to slender, more or less high-cespitose : 

 stem mostly with a central strand, with one to three innovations below the 

 apex, also with slender sterile shoots from the older portions; leaves 8-seriate, 

 gradually larger above, carinate or concave, ovate or oblong to lanceolate or 

 lance linear, acute to obtuse, non-bcrdered, mostly toothed above; costa mostly 

 incomplete, with median guides; areolation small, rounded, incrassate, mostly 

 papillose: sporogonia solitary; seta usually long, erect; capsule cernuous, rarely 

 erect, oblong to cylindric, with a short coUum, more or less 8-striate, plicate 

 when dry; annulus present; exothecial ce'ls elongate to rectangular, the longi- 

 tudinal walls thickened; phanerophore, stomata in the collum only; peristomes 

 free and essentially as in Byrum; spores .008-. 014 mm; operculum conic to ros- 

 trate; calyptra narrowly cucullate, Icng-rostrate, split on one side, fugacious. 



Inhabiting the colder and temperate parts of the world, in moist habitats 

 on soil, rocks, trees, etc. The genus Leptotheca with species in the south tem- 

 perate zone and the following: 



1. Aulacomnium Schwaegrichen 

 With characters as for the family, the stem sometimes bearing flagelliform 

 pseudopodia, which are leafless or nearly so and bear a cluster of gemmae at 



