Ptychostomum, Hornschuch, 1824

Spence, John R., 2020, Studies in Austral Bryaceae (Bryopsida) I. New Combinations in Ptychostomum Hornsch. from southern South America, Phytotaxa 437 (2), pp. 60-65 : 62-63

Subgenus Ptychostomum

1. Plants often pink to red, rarely green; spores 18–24 µm; capsule elongate-clavate, ± straight, peristome well-developed; sexuality dioicous................................................................................................................................................................................. P. pallens

- Plants green, yellow-green to brown; spores 12–35 µm, capsule turbinate to clavate, straight or rarely curved, peristome welldeveloped to strongly reduced; sexuality dioicous, autoicous or synoicous ......................................................................................2

2. Autoicous; plants green; leaf with distinct limbidium; spores> 30 µm, capsule elongate-clavate, somewhat curved; peristome reduced, cilia absent ........................................................................................................................................................... P. cernuum

- Dioicous or synoicous; plants green to yellow-green or brown; leaf limbidium present or absent; spores <30 µm; capsule turbinate to short-clavate, typically not curved, peristome well-developed to strongly reduced ......................................................................3

3. Leaves strongly recurved when wet, with narrow decurrent base; basal most proximal laminal cells somewhat inflated, distinct from cells above; capsule unknown ....................................................................................................................................... P. nivale

- Leaves erect but not recurved when wet, base broader, not decurrent; proximal laminal cells not inflated or distinct from cells above; capsules often present .............................................................................................................................................................4

4. Leaf margins plane; sexuality dioicous; spores 12–16 µm, capsule turbinate, cilia present and well-developed ......... P. turbinatum

- Leaf margin recurved proximally; sexuality synoicous; spores 22–26 µm, capsule clavate, cilia absent ................... P. mucronatum