Pterygoneurum undetermined

Fedosov, V. E., Fedorova, A. V., Ignatova, E. A. & Ignatov, M. S., 2025, On the genus Pterygoneurum (Pottiaceae, Bryophyta) in Russia, Arctoa 34 (1), pp. 31-43 : 41

KEY TO IDENTIFICATION OF PTERYGONEURUM SPECIES IN THE HOLARCTIC REGION

1. Setae longer than urn; capsules exserted ............. 2

— Setae shorter than urn; capsules immersed .......... 8

2. Leaf margins recurved to revolute; upper laminal cells with forked papillae on both surfaces ... P. volgense

— Leaf margins plain or slightly recurved; upper laminal cells smooth or with simple or forked papillae on dorsal surface ................................................... 3

3. Leaves short awned; lamellae without lateral outgrowths .................................................................. 4

— Leaves with long hyaline hair point; lamellae often with lateral outgrowths .......................................... 7

4. Capsules cylindric; opercula composed of cells in oblique rows; peristome remnants occasionally present; spores 20–26 µm ...................... P. arcticum

— Capsules ovate to short cylindric; opercula composed of cells in straight rows; peristome remnants absent; spores (22–)30–58 µm ........................................... 5

5. Distal laminal cells with forked papillae on dorsal side ..................................................... P. papillosum

— Distal laminal cells smooth or with simple papillae on dorsal side ......................................................... 6

6. Capsules short cylindric; spores 38–48 µm; [North Siberia] .............................................. P. ovatum p.p.

— Capsules ovate; spores 35–58 µm; [Mediterranean region] .............................................. P. sampaianum

7. Opercula composed of cells in oblique rows ........... ........................................................... P. lamellatum

— Opercula composed of cells in straight rows .......... ................................................................ P. ovatum

8. Capsules stegocarpous ......................... P. subsessile

— Capsules cleistocarpous ........................................ 9

9. Distal laminal cells with simple or forked papillae on dorsal surface; ventral lamellae 4–10(–15) cells high, with forked or C-shaped papillae; paroicous. .............................................................. P. sibiricum

— Distal laminal cells smooth or with simple papillae on dorsal surface; ventral lamellae 1–4 cells high, with simple papillae; perigonia well below perichaetia ........................................................... P. kozlovii