246 American Midland Naturalist Monograph No. 6 



3. Hygrohypnum oCHR^CEUM (Turner) Loeske 



(Hypnum ochrdceum Turner; Amblystegium ochraceum Lindberg; 

 Limnobium ochraceum Bryologia Europaea) 



Plate XLV 



Yellowish or rusty green, softly cespitose in wide tufts: stems up to 8 or 9 

 cm long, ascending or horizontally floating, sparsely and irregularly pinnately 

 branched, without rhizoids, the stems and branches somewhat hooked at the 

 apex, the cortical cells of the stem very large and thin-walled; leaves falcate- 

 secund, concave, plicate, widely lance-oblong to ovate-oblong, somewhat 

 rounded at the base, the margins plane, entire excepting for slight serration at 

 the rather widely sub-obtuse apex; costa single or double, often reaching half 

 the length of the leaf; median leaf-cells linear-vermicular, about 8-14:1, fair- 

 ly thick-walled, usually rounded at the ends, the apical oval-rhomboid and 

 much shorter, the basal l.-'.rger and towards the angles of the leaf forming dis- 

 tinct decurrent auricles of abruptly enlarged, hyaline, inflated, rectangular cells: 

 perichaetial leaves ecostate, lance-acuminate: seta slender, flexuous, erect; cap- 

 sules sub-erect to cernuous from a short erect coUum, oblong, arcuate; lid 

 convex, mamillate; peristome hypnoid, the teeth yellowish, broadly margined, 

 rather distantly trabeculate, equalled in length by the carinately split segments, 

 the cilia shorter, unequal, nodose, two or three in number; annulus large, usual- 

 ly 3-seriate; spores mature in spring or early summer. 



On rocks in streams or on dripping ledges, in the mountains of northern 



and temperate Europe and Asia, and, in North America, from the Arctic 



regions south to the latitude of New Jersey and West Virginia. 



Although rare in this district, so far as now known, this species may eventually be 

 found to be not uncommon in cool, rocky streams in the more mountainous parts of our 

 region. Fayette Co.: On rock in streim, Bl'e Hole Creek. C.M.B. lulv 5, 1948. 

 Westmoreland Co.: In mountain rivulet, Mellon's estate, Laurel Hill Mt., New Flor- 

 ence, September 8-10, 1907. O.E.J. Sterile (figured). 



4. Hygrohypnum Closteri (Austin) Grout 



(Hypnum Closteri Austin) 



Slender, in loose tufts, green to yellowish; stems creeping, irregularly 

 branched; leaves rather widely spaced, spreading, not or rarely secund, leaves 

 ovate or oblong-ovate, rarely reaching 1 mm long, flat apex obtuse, margin 

 entire, only very slightly decurrent; costa normally single, reaching to mid- 

 leaf or beyond; median leaf-cells linear, somewhat opaque, about 3-5:1, apical 

 shorter; basal shorter and wider, alar but little enlarged: seta 6-8 mm long, 

 castaneous; capsule, brown, ovoid, cernuous, arcuate, much constricted below 

 mouth when dry and old; annulate; lid low-conic, apiculate; spores ripe in 

 spring. 



On stones in cool streams. Vermont to eastern Pennsylvania and Virginia, 

 but not yet found in our region. 



4a. Hygrohypnum Closteri f. serru latum Grout 

 Lseaf-cells more hyaline; leaves often serrulate above. 

 McKean Co.: Bolivar Run, Burnett No. 3208 (Type). September II, 1898. 



