Chapter DIV: I. Calyptra dimidiate

SUB-DIV. I. _Peristome none._

ANŒCTANGIUM (72). Caps. oval or obovate, erect, with a short slightly inflated neck; lid conico-convex with a long slender oblique beak; stems erect, cæspitose. 139.

SUB-DIV. II. _Perist. single, of 16 teeth._

HABRODON (77). Caps. oval-oblong erect, calyptra large, lid conical; st. sub-erect, l. spreading, nerveless, soft and opaque; per. teeth simple, linear, inserted below mouth of caps., remotely articulate: dioicous. 141.

SUB-DIV. III. _Peristome almost single._

_a._ _inner peristome very short and indistinct._

LEUCODON (73). Caps. oval erect, on a short pedicel; calyptra large; outer teeth 16 bifid or perforate, not hygroscopic; surculi erect simple; leaves plicato-striate, nerveless. 139.

PTEROGONIUM (78). Caps. oblong erect, on a long seta; calyptra small; outer teeth 16 simple, hygroscopic; surculi dendroid, with fasciculate curved branches; leaves not striate. 141.

LEPTODON (75). Caps. oval on a very short seta; calyptra and vaginula hairy; teeth 16 linear-lanceolate, entire or fissile, not hygroscopic; surculi pinnate; branches curled when dry; leaves very obtuse. 140.

SUB-DIV. IV. _Peristome double._

_a._ _Inner perist. of 16 cilia._

ANTITRICHIA (74). Caps, oval, regular, on a short curved seta; calyptra rather large smooth; inner peristome of 16 filiform processes; outer 16 tapering teeth with a medial line; surculi procumbent, pinnate. 140.

ANOMODON (76). Caps. oval-oblong erect, on a long seta; lid obliquely rostrate; calyptra small; perist. as in last: stems erect with erect branches, cæspitose; leaves of close texture acuminate, nerved. 140.

CYLINDROTHECIUM (81). Caps. cylindrical, regular, erect; outer teeth 16 inserted below mouth of capsule; inner of 16 narrow carinate processes; lid shortly rostellate; stem procumbent pinnate; leaves ovate concave, faintly two-nerved at base. 142.

NECKERA (85). Caps. oval-oblong, immersed or pedicillate; lid obliquely rostrate, outer teeth 16 linear-subulate, long, connivent into a cone; inner as above; stems pinnate; leaves complanate. St. sub-erect from a creeping rhizome. 182.

_b._ _Inner peristome a membrane divided half way into 16 carinate
segments with or without cilia._

* Caps. symmetrical, erect or sub-erect.

OMALIA (84). Leaves complanate smooth, falciform, obtuse, serrulate at apex, not undulate (allied to _Neckera_).

LESKEA (82). Perist. outer of 16 narrow barred teeth, inner without (rarely with) intermediate cilia, leaves mostly ovate, nerved or nerveless, entire, spreading every way. 143.

CLIMACIUM (80). Caps. oblong, erect; lid adhering to the persistent columella; outer teeth linear-lanceolate, confluent at base, trabeculate, with a medial line; inner alternate and longer than outer, lacunose without cilia, the two segments of each process united only at apex; stem dendroid, erect. 142.

ISOTHECIUM (79). Caps. oval, sub-erect, symmetrical; lid not adhering to columella; outer teeth 16 barred, with a medial line; inner with intermediate cilia, two or three together; stem dendroid drooping; branches fasciculate or pinnate. 142.

* * Caps. unequal, cernuous.

HYPNUM (83). Caps. cernuous, sometimes nearly erect, rarely pendulous, ovate or oblong, more or less curved, and sometimes slightly apophysate; outer teeth 16 equidistant lanceolate acuminate, barred, inner alternating, often perforate, with intermediate cilia, one, two or three together. 145.

_c._ Inner perist. a reticulated cone.

DICHELYMA (90). Peristome like _Fontinalis_; caps. scarcely exserted; calyptra long twisted; leaves nerved. 185.