Ptychomitrium polyphyllum

Found at Carlingnose Point, in the only hectad in the county with a previous record. Nice moss, recently encountered on an outing in D&G too. Ptychomitrium means folded mitre, presumably because of the lines on the capsule. Leaves crisp on drying and even a bit of dryness sees them start to curl over.

(Frey keying:
Acrocarps, p.141
1. Not Buxbaumidae
2. Not Tetraphidae
3. Not lfs strictly in two rows
7. Not filaments on ventral costa
9. Upper laminal cells +/- isodiametric
37. Not Cinclidotaceae
38. Not capsules globose
39. Not Meesiaceae
40. Lower laminal cells weakly differentiated (I take issue with this, as with Didymodon rigidulus!)
44. Leaf margins unbordered
45. Plants forming small cushions or patches on rocks, lvs crisped when dry, laminal cells smooth, capsules usually present, ovoid-ellipsoid, calyptra mitrate (?) ->Ptychomitriaceae, p.275

1.3.4. Leaf margins dentate, blackish below, seta yellowish, capsules ellipsoid, on exposed rocks and walls

Nestling in a R.fasciculare cushion

Torn calyptra is typical, curling leaves

Blanket of revolute margins

Leaves

Toothed margin towards apex

Leaf section (not bad, eh?)