Holotype: Atrichum lescurii T. P. James, Bull. Torrey Club 6: 33. 1875.
This distinctive, monotypic genus was merged with Lyellia by Salmon (1901),
but apart from the lack of a peristome, Bartramiopsis and Lyellia have little in
common. The capsule of Bartramiopsis does not develop the conspicuous disc
characteristic of Lyellia and Alophosia, and unlike the strongly dorsiventral,
angled capsules of these genera, the fruit of Bartramiopsis is terete and campanulate,
like that of the South American Dendroligotrichum dendroides (Hedw.)
Broth., although much smaller and with the stomata confined to the gradually
tapering apophysis, and not dispersed over the whole exothecium.
The strong convexity of the upper layer of cells of the bistratose leaf lamina
suggests both Lyellia and Alophosia. This condition results from the apparent
loss of lamellae except for those along the median portion of the leaf, without
the loss of the ventral cells, which retain their size and shape. Strongly convex
ventral cells are also characteristic of Dendroligotrichum, Microdendron, and a
number of Pogonatum species. Compared with Lyellia, Bartreimiopsis is more
slender in all its parts, although in this respect it does not differ from Alophosia.
As in Alophosia, the stem of Bartramiopsis has an indistinct central strand, composed
of only slightly thickened hydroids.
Bartramiopsis lescurii has many unique features, among them the sharply
serrated lamellae, and the long cilia borne on the margins of the leaf sheath (Fig.
64). Whatever its relationships, Bartramiopsis seems abundantly deserving of its
independent generic status.
The distribution of Bartramiopsis (Schofield, 1965; Fig. 90) indicates that
it belongs to the group of plants called southern Beringia radiants by Hulten
(1937). These distinctly oceanic plants were presumably uniformly distributed
over their present Asian and American areas as well as the coast of southern
Beringia before the period of maximum glaciation. This area was then broken
up by the relatively severe climatic conditions prevailing in Beringia during
maximum glaciation. In the case of Bartramiopsis, the old area may have been
partially restored by northward radiation in postglacial times.