52 American Midland Naturalist Monograph No. 6 



dish-pellucid, mature in early summer; operculum conic-obtuse, about 6 mm 

 long; calyptra smooth, cucullate, slenderly straight-rostrate, about 2.5 mm 

 long, the beak reaching about 1.5 mm beyond the tip of the operculum; anther- 

 idial clusters gemmiform in axils of the perichaetial leaves. 



On bare soil, usually in woods. Europe, Asia, northern Africa, and, in 

 North America, from Nova Scotia to Ontario south to the Gulf of Mexico 

 and westward to Kansas. 



Common in our region, and now known from the following counties: Allegheny, Arm- 

 strong, Beaver Bedford, Butler, Centre, Crawford, Fayette, Lawrence. McKean, Washing- 

 ton, and Westmoreland. Specimen figured: Blackburn, Westmoreland County, O.E.J. 

 June 13, 1908. 



5. Ceratodon Bridel 



Dioicous, rarely autoicous; cespitose, green to brown or reddish-brown, 

 somewhat radiculose; stem 3-5-angled, with a central strand, thickly foliate, 

 often bushy-branched; leaves erect-spreading, appressed and more or less 

 twisted when dry, ovate to lance-linear, neither sheathing nor subulate-pointed, 

 margin revolute; costa strong, percurrent or long-excurrent, with median guides; 

 leaf-cells thick-walled, short-rectangular below, the upper quadrate to rounded, 

 smooth; perichaetial leaves distinctly sheathing; seta long and erect; capsule in- 

 clined to horizontal, elliptic-ovate to oblong, purplish to reddish-brown, shining, 

 when dry sulcate; annulus spirally deciduous, 2-4-seriate; peristome- teeth 16, 

 cleft nearly to the base into filiform divisions, united at the base into a tube, 

 the teeth closely articulated below, less closely above, papillose; operculum 

 conic, much shorter than the capsule; calyptra cucullate. 



A cosmopolitan genus consisting of 27 * species; 4 species in North Amer- 

 ica, only one occurring in our region. 



1. Ceratodon purpureus (Hedwig) Bridel 



{Mnium purpureiim Linnaeus; Dicranum purpurascens Hedwig; 

 Dicranum purpureum Hedwig) 



Plate X 



Densely and often rather deeply brownish- or reddish-cespitose, mostly 

 green above and dark brown below: stems mostly branched, erect, about 1 cm 

 high, dying away below; leaves lanceolate to linear-lanceolate, carinate, the 

 margins revolute to near apex; costa strong, percurrent, at base about one- 

 sixth to one-fourth the width of the leaf; seta about 1.5 cm long, erect, dark- 

 castaneous, lustrous, twisted when dry; capsule oblong-linear, at first erect, later 

 inclined to horizontal and more or less curved, irregularly sulcate, strumose, 

 about 2.5 mm long, dark red-brown, lustrous, annulus distinct, revoluble; peri- 

 stome-teeth dark red below, basally confluent, papillose, weakly trabeculate to 

 a little above the middle, bordered, hyaline above; operculum conic-elongate, 

 about one-fourth the length of the urn, often somewhat curved, usually darker 



* Brotherus (Pflanzenfamilien, 1924, 2nd. edit, p. 163) thinks these all can be 

 reduced to two species. 



