Ptychostomum turbinatum, also known as topshape thread-moss or pear-fruited bryum, is a species of moss found in continental Europe and the US.

[1][2] The species became extinct across the British Isles in the 1940s according to the Species Recovery Trust and in 2001 according to the IUCN, and it has not reestablished since.

[3][4][5] Splachnobryum kieneri is listed by the USDA as a synonym.

[6] It grows on the edges of ditches and ponds, on calcareous,[7] gravelly ground.

The leaves' color ranges from dull green to yellow-green.