444 Proceedings of the Royal Irish Academy^ 
aa. Leaves ovate or ovate-acuminate, secimd. 
Dioicous. 
Stem procumbent or sub-erect, sparingly and 
irregularly branched ; branches subcom- 
planate ; leaves complanate, sub-secund, 
lax, ovate-lanceolate, nerveless ; capsule 
turgid, ovate, plicate when dry ; lid 
conical, ...... 46. H. LmnBERGii. 
Stem erect or procumbent, irregularly pin- 
nate ; leaves imbricate, secund, broadly 
ovate or roundish, nerveless or faintly 
two-nerved at base, falcate at the apex of 
the branches, . . . ; . 47. H. scorpioides. 
aaa. Leaves mostly falcate, secund, nerve thin. 
Stem subpinnate ; cauline leaves crowded, 
secund; branch leaves falcate -secund, 
ovate-acuminate, concave, large, nerved 
nearly to the apex. Dioicous, . . 48. H. lycopodioides. 
Stem subpinnate ; branches simple, uncinate ; 
cauline leaves broadly ovate at base ; 
branch leaves falcate- secund, lanceolate- 
subulate, concave, slightly striate, nerve 
reaching half way. Dioicous, , . 49. H. vernicosum. 
Stems crowded, erect or procumbent, leaves 
circinate, secund, ovate- acuminate, sub- 
serrulate at the apex, nerve reaching 
above half way up. Monoicous, . 50. H. revolvens. 
Stem pinnately branched ; leaves circinate, 
secund, ovate-acuminate. Dioicous, . 5L H. intermedium. 
Stem erect or procumbent, pinnate; leaves 
falcate- secund, lanceolate-subulate from 
a broad base, serrate, striate, nerve 
reaching almost to the apex. Monoicous, 52. H. uncinatum. 
Stem flaccid, elongate, branches pinnate ; 
leaves rather loose, secund, falcate, ovate- 
acuminate, channelled or striated ; nerved 
to the apex ; capsule exannulate. Dioi- 
cous, 53. H, EXANNTJLATUM. 
