286 A MANUAL OF MOSSES 



8. ACROCLADIUM Mitten. 



Autoicoiis or dioicous: robust; rather stiffly but loosely 

 cespitose, lustrous, green to yellowish or brownish ; stems long, 

 densely foliate, the dpex of the shoots rigid and acuminate by 

 reason of the convolute apical leaves,- the stems erect, not bear- 

 ing rhizoids, and rather regularly complanately pinnate, or 

 procumbent, here and there with fascicles of rhizoids, irregu- 

 larly branched; leaves appressed, smooth, drying somewhat 

 imbricate, when damp erect-spreading, concave, from a narrow 

 and sub-decurreht base broadly oblong-ovate, obtuse, rarely 

 apiculate, entire, the margin apically rnore or less involute ; 

 costa double, short, or none; leaf-cells narrowly vermicular, 

 smooth, wider and porose towards the base, in the excavate 

 alar portions lax, oval-4-6-sided, hyaline, thin-walled, forming 

 a distinct auricular groiip ; inner perichaetial leaves erect, en- 

 tire : seta i-7 cm. high, twisted, reddish ; capsule horizontal 

 from an erect collum, oblong to cylindric, drying arcuate and 

 dorsally gibbous, smooth or plicate, little narrowed below the 

 mouth; peristome normally hypnoid with appendiculate cilia; 

 lid convex-conic. 



As here recognized the genus consists of 3 species ; two in 

 the Southern Hemisphere and the following: 



i. Acrocladium cuspidatum [Linnseus] Lindberg. 



(Hypnuni cuspidatum Linnjeus; H. flexile Bridel ; Callicrgon 

 cuspidatum Kindberg). 



(Plate XL) 



Tall and moderately robust \yith characters mainly as out- 

 lined for the genus : leaves usually bright, glossy, yellowish- 

 green, or almost pure green, broadly ellijptic-oblong, up to 2.5 

 mm. long, concave-cucullate, entire, the apex often apiculate, 

 ecostate or the costa short and double, leaves crowded, usually 

 more or less erect-spreading when moist, towards the tips of 

 the stems and branches imbricate-convolute so as to make the 

 tips cuspidate ; median leaf-cells linear-vermicular, about 

 10-15:1, the alar suddenly inflated, thin-walled, hexagonal, 

 hyaline or colored, forming a very distinct group, the apical 

 rather abruptly shorter, rounded, and incrassate : seta 4-6 cm. 

 long; capsule reddish-brown; peristome-teeth orange, hyaline- 

 bordered, the margins step-like above; cilia 3, appendiculate, 

 slightly shorter than the narrowly cleft segments ; spores ma- 

 ture in summer, the large capsules being but rarely pro- 

 duced ; annulus 3-seriate. 



In marshy places, swamps, and bogs ; Europe, Asia, north- 

 ern Africa, and, in North America, through Canada and the 

 northern part of the United States. Rather uncommon in 

 our region. 



