J. Guerra et al., PTERYGONEURUM-SUBSESSILE (BRID) JUR VAR KIENERI HAB (MUSCI, POTTIACEAE), A PUTATIVE HYBRID, Nova Hedwigia, 58(3-4), 1994, pp. 507-510
The hybrid origin of Pterygoneurum subsessile var. kieneri is postulat
ed. The type material studied presents cleistocarpous capsule similar
to those of Phascum cuspidatum and intermediate gametophytic character
s between Pterygoneurum ovatum and Phascum cuspidatum, species observe
d together in the same sample.