Pleurocarps with curved leaves

(If you need to know what a pleurocarp is, click here)

A. Brachythecium

B. Other or unknown — 1

1 Stems red; robust, rigid, irregularly pinnately branched; abundant in upland woods and on hillsides in wetter districts of north and west — Rhytidiadelphus loreus

Stems green or blackish; habitats various — 2

2 On trees — Hypnum cupressiforme

Some other habitat — 3

3 Terrestrial: on banks, wall-tops, stony ground, etc. — 4

Semi-aquatic: in marshes or bogs, or on wet rocks by streams and lakes —7

4 Shoots tending to be flattened in one plane, up to 4-5 mm. wide; leaves often transversely wrinkled; plant of calcareous rocks — Neckera crispa (falcate forms)

Shoots not tending to be flattened in one plane, not above 2 mm. wide — 5

5 Plant with numerous nearly erect shoots, themselves sparingly branched; glossy, light yellowish green plant of grassy banks, etc., chiefly on acid soils — Brachythecium albicans (Brachythecium key)

 Shoots mainly prostrate or nearly so, with numerous pinnate branches — 6

6 Branches very crowded; shoot tips notably pale green, their ends strongly curled in various directions; abundant in calcareous habitats — Ctenidium molluscum

Branches not crowded; all leaves regularly curved and turned downwards (but not strongly curled as above); abundant, wide- spread, very variable species — Hypnum cupressiforme

7 On rocks, by lakes, streams or waterfalls — 8

On peaty or other soil, in marshes, bogs or pools —13

8 Plant dark red-brown, purple-brown or blackish green; primary stem prostrate with long (8-15 cm.), little branched, nearly prostrate secondary shoots — Scorpidium scorpioides

Plant yellowish green to golden; secondary shoots either short, erect and nearly simple or long and freely branched —9

9 Primary stem prostrate with few or many short, nearly simple erect or ascending secondary shoots — 10

Secondary shoots long and freely branched, often regularly pinnate — 11

10 Shoots bright glossy green, tinged golden brown; leaves crowded; leaf apex acute — Brachythecium plumosum (Brachythecium key)

Shoots dull yellowish green to brownish; leaves not crowded, lower parts of stems often quite bare of leaves; leaf apex blunt — Hygrohypnum palustre

11 Older stems much interwoven with red-brown tomentum (rhizoids); leaves uniformly and strongly curved; nerve present —  Cratoneuron commutatum (Cf. also C. filicinum, which has shorter, much less strongly curved leaves.)

Red-brown tomentum lacking; leaves more strongly curved at shoot tips than elsewhere; nerve absent —12

12 Young shoots very small and crowded, their leaves strongly curled; on calcareous rocks — Ctenidium molluscum

Young shoots not crowded, often elongated, their leaves only lightly curved; mainly on siliceous rocks by waterfalls, etc. — Hyocomium armoricum

13 Leaves only about 1 mm. long; on wet ground in lime-rich marshes and fens — 14

Leaves longer (2-4 mm.); habitat various, but rarely as above — 15

14 Young shoots very small and crowded, their leaves strongly curled; nerve absent — Ctenidium molluscum

Young shoots not crowded, nerve present — Cratoneuron filicinum

15 Leaves crowded; noticeably broad, concave and shortly pointed at their tips; dark red-brown, purplish or blackish green plant with long, prostrate, little-branched shoots on wet peat — Scorpidium scorpioides

Leaves finely pointed; combination of leaf shape and habitat not as above; habitats various —16

16 Leaves strongly and uniformly curved (almost to form semi-circle); shoots often variegated orange and crimson — Drepanocladus revolvens

Leaves slightly curved, or rather strongly curved only at shoot tips — 17

17 Whole plant glossy yellowish green; leaves not above 2 mm. long; on wet ground — Brachythecium rutabulum (marsh forms) (Barchythecium key)

Plant blackish below, dull or glossy yellowish green or reddish above; leaves 3-4 mm. long; chiefly in pools —18

18 Plant light green or yellowish; leaves often nearly straight, usually rather wide with fairly short fine point — Drepanocladus aduncus

Plant usually dark, often dark olive-green or reddish above and brown or black below; leaves rather strongly curved at shoot tips, very narrow and finely pointed; in acidic (base-poor) waters — D. fluitans or D. exannulatus

(N.B. In some districts, especially in mountain habitats, D. exannulatus is commoner than D .fluitans. The two cannot be separated with certainty except under the microscope.)

If moss does not key out here, try the other pleurocarps key or the Brachythecium key.


For comments about this site please mail to:

(e-mail address given as graphic to avoid spam)