Hypnum.] BRYACE^. 321 



oval, the alar quadrate or ti'ansversely oval, not enlarged ; 

 branch-leaves much smaller, ovate-acuminate, all minutely ser- 

 rulate ; paraphyllia few, leaf-like. Capsule oval or oblong, 

 curved. Peristome large ; cilia 2 or 3. — Heterocladium^ Bruch 

 & Schimp. 



4. H. dimorphum, Brid. Dioecious : plants loosely ces- 

 pitose, entwining, rigid, yellowish gi-een : stem-leaves ovate- 

 lanceolate, long-acuminate, broadly cordate and decurrent at 

 base, curved back from the middle ; costa very obscure, short 

 and geminate ; branch-leaves suberect, ovate, concave, obtuse, 

 imbricate ; para])hyllia few and small, filiform or oval, ciliate ; 

 perichffitial leaves long, ecostate, reflexed from the middle, 

 whitish : capsule oblong, incurved or horizontally inclined, 

 slightly constricted under the orifice ; lid short, conical-obtuse. • 

 — Muse. Recent. Suppl. ii. 1-19. Heterocladium dimorphum, 

 Bruch & Schimp. Bryol. Eur. t. 479. 



Hab. White Mountains and Nova Scotia (James). 



5. H. procurrens. Dioecious: plants yellowish green; 

 stems arcuate, procumbent; branches irregularly pinnate or 

 bipinnate : stem-leaves divergent, compressed, gradually nar- 

 rowed to a filiform point, minutely serrulate on the borders, 

 with two unequal costae vanishing in the middle ; areolation 

 elongated in the middle of the leaves, oblong on the margins 

 and toward the apex, all smooth and pellucid ; branch-leaves 

 unequilateral, obtuse ; the perichjetial broadly ovate, convolute 

 at the base, spreading at the apex : capsule oval, horizontal, 

 long-pedicellate. — Pteroffonium procurrens, Mitten, Journ. 

 Linn. Soc. viii. 37, t. 7. 



Hab. British America (Drummond). 



Of looser habit than the last. Pedicel an inch long. 



Subgenus III. THUIDIUM. (PI. 6.) 



Primary stems densely rooting, the secondary 1-3-pinnately 

 ramulose. Stem-leaves larger, decurrent, cordate-triangular, 

 more or less long-acuminate, strongly costate, papillate on the 

 lower face or on both; paraphyllia numerous and multiform; 

 branch-leaves smaller, ovate-lanceolate, concave, imbricate; 

 areolation small, round-hexagonal, sometimes long-linear at 



