Flora of North America species comparison

Campylopus introflexus occurs in masses in sand dunes along the west coast of North America and throughout the Southern Hemisphere. The species was introduced in Great Britain in 1942, and since the beginning of the 1970s has been aggressively spreading through Europe. It now ranges from Iceland to Spain and from Ireland to Poland. The first record in North America dates from August, 1975, and was made on a gravel roof of a building of Humboldt University, Arcata, California. The species is undoubtedly introduced in North America and is spreading here as rapidly as in Europe. The name C. introflexus was used previously for C. pilifer, thus all old references for C. introflexus in North America have to be referred to that species. Also, specimens of C. surinamensis and C. oerstedianus from North America were named as C. introflexus. Campylopus introflexus is easily recognized by the reflexed hair points. Female plants have terminal perichaetial buds. Problems may rarely arise with forms from shaded habitats, in which the hairpoints are absent or so short that they are not reflexed.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The disjunction of Campylopus tallulensis from southeastern North America to Mexico, which is also met in other bryophytes and flowering plants, is considered to be a result of a former continuous range in the Tertiary. Campylopus tallulensis was included in C. flexuosus by American authors. There is a superficial similarity regarding the habit and the shape of the distal laminal cells. Campylopus flexuosus is, however, easily distinguished by thick-walled basal laminal cells and the presence of microphyllous brood branches. Plants of C. tallulensis from Mexico and eastern North America are robust and yellowish to golden green. In contrast, the specimens collected in Illinois, Mississippi (in part), and Arkansas are more slender and dark green, resembling C. subulatus in appearance. It is not known whether these differences in color depend on a different geological substrate or are the expression of different populations. Both species are anatomically very similar with thin-walled hyaline basal laminal cells, almost quadrate distal laminal cells, a costa excurrent in a sometimes subhyaline point and being roughened at the abaxial side like a rat’s tail file and a channeled leaf apex. The only way to distinguish both species seems to be the transverse section of the costa, which shows very distinct groups of abaxial stereids in C. tallulensis but no abaxial stereids in C. subulatus. Furthermore, the adaxial hyalocysts of C. tallulensis are twice as wide as those of C. subulatus (J.-P. Frahm 1994). On the basis of this character, the only records of C. subulatus in North America from California belong to this species and are not extensions of the range of C. tallulensis from Mexico.

(Discussion copyrighted by Flora of North America; reprinted with permission.)