— 125 — 
gen. thick. Stem us. not pinnate, r. with paraphyllia. Leaves 
sometimes not faleate. 
III. Harpidium. Leaves gen. not mamillose, in few species 
striate; cells gen. narrow exc. the gen. hyaline or sometimes 
not distinct alar; costa gen. not thick. Stem us. not radiculose, 
. sometimes pinnate; paraphyllia wanting. Leaves (in few species) 
. sometimes not falcate. 
aa. Alar leaf-cells not distinct. 
= I Riparia. Leaves gen. straight subdistichous; lower basal 
= œlls nearly uniform subquadrate in 2—5 rows. Monoecious 
often fruiting. Stem often radieulose. — Growing princ. on 
logs in water. 
. 2, Revolventia. Leaves falcate; lower basal cells gen. few, 
short and dilated. Sometimes monoecious. Stem not radiculose. 
. Leaves often reddish. — Growing in swamps. 
= bb. Alar leaf-cells distinct. 
3, Adunea. Leaves not r. straight (princ. in H. fluitans, H. 
exannulatum and H. elodes), r. plicate when moist. Us. dioe- 
cious, not often fruiting. Stem r. radiculose. Leaves sometimes 
(prine. in H., exannulatum) reddish. — Growing in swamps. 
4. Unecinata. Leaves us. falcate, gen. plicate. Us. monoecious, 
often fruiting. Stem r. radiculose. Leaves greenish. — Growing 
on dry stones, base of trees and dry earth, r. in water, 
. b. Leaves recurved at borders below, subundulate when dry. 
Ty, Rhytidium. Leaves faintly rough above at both sides, 
faleate or nearly straight; alar (angular) cells small very nume- 
rous.: Stem without rhizoids and paraphyllia. 
B. Leaves with short double or indistinct (in H. resupinatum 
Sometimes simple) costa, falcate or (sometimes In H. cupressi- 
forme) straight, sometimes (in subg. Cupressma and Campylo- 
ullum). recurved at borders. Stem sometimes (in Cupressina) 
Wilh paraphyllia. Dioecious or monoecious. 
Ye Pseudo-Hylocomium. Leaves spreading when dry, large 
enticulate not circinnate, us. plicate below; special alar cells 
Not defined. Stem not or irregularly pinnate, not creeping. 
. Be —— e do. MD 
> ampylophyllum. Leaves spreading when , 
: ood: "ra ta subcircinnate - plicate; alar cells small 
“istinct. Stem pinnate creeping. Monoecious. 
: VIL. Tamea Leaves me spreading when dry, pT 
entire not. circinnate, sometimes striate or plicate; alar 
