60 MEESEACEAE 



ACAULON C. Muell. 

 The species of this genus are distinguished by their broadly 

 ovate loosely areolate smooth costate leaves; leaves and leaf 

 cells broader and proportionately shorter than in Ephemerum, 

 but growing in the same situations. Early spring. 



Perichaetial and upper leaves carinate, margins reflexed triquetrum 



Perichaetial and upper leaves concave, margins plane rufescens 



A. rufescens Jaeg. Fields Brooklyn, Austin (24270)!; "old 

 fields, N. J.," Muse. App. 51; Closter, Austin, Bx!; Tottenville, 

 S. Id., E. G. B., Bx! 



A. triquetrum (Spruce) CM. "Sandy fields, Toms River, N. 

 J.," Muse. App. 52. 



Family 16. MEESEACEAE 



Plants of wet boggy places, frequently growing with Sphagna. 

 Leaves spreading to squarrose-recurved, of a rather firm struc- 

 ture, ovate-lanceolate to elongated-lanceolate. Costa long and 

 stout, ending a little below the apex. Leaf cells smooth 

 (papillose in Paludella), rather small above, large and more 

 elongated below. Seta usually very long and slender. Calyptra 

 cucullate. Capsules curved-pyriform, with a conspicuous neck, 

 smooth or somewhat striate when dry; operculum small, short 

 conical; mouth small; annulus of one or two rows of cells; peri- 

 stome double, the inner usually much longer than the outer 

 and consisting of 16 narrow segments alternating with the teeth, 

 cilia sometimes present. 



All of our mosses of this family seem to be rather rare. The 

 bog habitat, the long seta and the curved pear-shaped capsules 

 with a small mouth, clearly establish the identity of any mem- 

 ber. 



MEESEA Hedw. 



Stems more or less elongated and radiculose. Upper leaf 

 cells rectangular to hexagono-rectangular. Neck of capsules 

 long; segments of inner peristome often united by lateral hair- 

 like appendages bearing nodules; teeth short, usually obtuse. 

 The spores of our species ripen from late June to August. 



o 



M. triquetra (L.) Angstr. 'Wet meadows. Closter, N. J.," 

 Muse. App. 217. 



