76 American Midland Naturalist Monograph No. 6 



A. Small little-branched plants, up to 4 cm long: seta longer than the capsule 



2. O. Hallianum 



1. OcTODICERAS DEBILE (Schwaegrichen) Jennings 



(Octodiceraf julianus Bridal; Cor.omitrium Julicinum Montagne; 

 Fontinalis Juliana Savi) 



Plate LXI 



Plants up to 15 cm long, flaccid, floating, blackish-green below, much 

 branched: leaves up to 5 or 6 mm long, distant, spreading, numerous, linear- 

 lanceolate, entire, non-bordered, vaginant lamina one-fourth to one-third the 

 length of the leaf, inferior lamina not quite reaching base, costa ending slightly 

 below the apex; leaf-cells irregular hexagonal or more quadrate below, about 

 .015-.020x .020-. 030 mm, somewhat incrassate, within the border at the lower 

 outer corner of the vaginant lamina several rows of elongated linear-oblong 

 cells: seta shorter than capsule, pale, fragile at base, elliptic, erect, scarcely 

 raised above perichaetical bracts, symmetric; operculum conic-rostrate and 

 about as long as urn; peristome-teeth short, imperfect, 16, yellowish-pellucid, 

 irregularly cleft and perforate in upper part; calyptra conic, dark, erose at 

 base; spores about .020-. 022 mm, mature in summer. 



Almost cosmopolitan, but rather local, on stones and on wood in creeks 

 and springy swamps. 



This species has not been collected in western Pennsylvania except as follows: BuTLER 

 Co.: Walley Mill region^ Parker Twp., on submerged rocks in brook. Sidney K. East- 

 wood, July 14, 1935 (figured). Crawford Co.: On clay bank along Shenango River, 

 west of Lineville. W. R. Van Dersal, Oct. 15, 1933. Huntingdon Co.: Porter. 

 (Porter's Catalogue.) 



2. OcTODiCERAS Hallianum (SuIIivant and Lesquereux) 

 Jaeger and Sauerbeck 



{Conomitrium Hallianum SuIIivant and Lesquereux; Fissidens Hallianus Mitten) 



Plants smaller, up to 3-4 cm long, laxly tufted, dirty-green: stems sparsely 

 fasciculate-branching at base; leaves remote, narrowly linear-lanceolate, usually 

 in 5-10 pairs, entire, the sheath not reaching over one-fourth or one-third the 

 length of the upper pair of leaves, inferior lamina narrowing and reaching 

 almost to the base; cells irregularly hexagonal, tending to quadrate below, 

 about .015-. 022 mm: seta longer than capsule, pale; capsule pale, elliptic-oblong; 

 peristome-teeth undivided, reddish, subulate-lanceolate, articulate, inserted 

 below the mouth of urn, papillose; operculum acutely conic-rostrate and about 

 as long as urn; calyptra cucullate, covering the entire operculum; spores smooth, 

 about .018-.024 mm. 



On wood and stones, in streams, swamps, etc., New Jersey, New York, 

 Illinois, and Idaho. Not reported for our immediate region, but perhaps 

 overlooked on account of small size. 



Family 5. Pottiaceae 



Autoicous or dioicous, rarely par-, syn-, or polyoicous: mostly small or 

 medium,-sized, more or less densely cespitose, rarely gregarious: stems mostly 



