135 
ISOTHECIACEAE Spruce, Ann. and Mag. Nat. Hist. (II.) 3: 
285. 1849. 
.. Gametophyte generally large, never minute. Primary stems 
creeping, radiculose. Paraphyllia lacking (except in C/zaczum). 
Leaves smooth, often plicate or concave ; median leaf-cells linear, 
alar cells quadrate (except in Holmgrenia). Sporophyte long ex- 
serted. Seta smooth, twisted. Calyptra cucullate. Operculum 
conic to conic-rostrate. Columella persistent. Capsule erect, 
straight, not conspicuously contracted under the mouth when dry. 
Peristome double, well developed; teeth lanceolate, articulate. 
Segments of endostome linear to lanceolate, attached to a narrow 
basal membrane, free, or adherent to the teeth in two species of 
Pylaisiella ; cilia rudimentary or wanting. Spores roughened. 
Distinguished from the Brachytheciaceae by the straight erect 
capsule not contracted under the mouth when dry, absence of 
cilia and short basal membrane. 
Homalothecium and certain species of Brachythectum (notably 
B. acuminatum) have the capsule characters of this family, but 
their other characters show their relationship to be with the 
Brachytheciaceae. 
Key to the Gen 
Leaves costate, costa single, extending to the middle of me leaf or beyond. 
4. CLIMACIUM. 
Leaves ecostate or the costa short and double. 
Alar cells not quadrate. 3. HOLMGRENIA. 
Alar cells quadrate. 
Leaves complanate (except E. repens and E. ces act i ion large, 
persistent (except E. Drummondit). TODON. 
Leaves more or less falcate-secund especially at the tips of airte annulus 
narrow. . PYLAISIELLA. 
1. ENTODON C. Muell. Linnaea, 18: 704. 1844. Also Bot. 
| Let. 2: 740... 1844. 
[CvriNpRoTrHECIUM Br. & Sch. Bryol. Eur. fasc. 46, 47. pl. 
464, 465. 1851.] 
Gametophyte growing in Wide intricate mats. Stems densely 
leafy, creeping, subpinnately branching (stems erect and pinnate 
in Æ. orthocarpus); stem and branches more or less complanate- 
