Dicranum pyriforme Schultz
Plants 3 mm, gregarious or in loose, low tufts, forming low rosettes, appearing stemless, light to olive green. Leaves 3 mm, erect-patent, flexuose when dry, from lanceolate base gradually contracted into a long, fine, straight, concolorous subula which is distinctly canaliculate; margins serrate in the distal part of the leaves; alar cells scarcely differentiated; basal laminal cells hyaline, thin-walled, rectangular; distal laminal cells thick-walled, rectangular, ca. 4:1; costa filling 1/2--2/3 of leaf width, excurrent, in transverse section with large, empty, adaxial hyalocysts and abaxial groups of stereids, smooth at back. Specialized asexual reproduction by colorless, multicellular, long cylindric rhizoidal tubers, 300--700 µm long, deciduous leaves and small brood leaves produced at stem tips. Sporophytes not present in North America.
The description refers to North American plants---specimens from other parts of its range can look differently. This species was first recorded for North America (T. Arts and J.-P. Frahm 1990) based on collections made by W. D. Reese. The occurrence in North America at only three localities in Louisiana and Mississippi, and an additional unpublished record from Florida can perhaps be explained by introduction that was facilitated by the presence of rhizoidal tubers. It may therefore be doubted whether this species is native in North America. However, the small form found in the United States resembles a form that occurs in Brazil in similar habitats, from where it might have been introduced by birds. Similar disjunctions between Brazil and se North America are also found in Campylopus surinamensis, C. carolinae and C. angustiretis, which all conspicuously grow together on bare, acid, white sand. Campylopus pyriformis was also found mixed with C. surinamensis, but can be distinguished by the more elongate, narrow lanceolate leaves with a channelled apex, a longly excurrent nerve and a lamina ending at midleaf and colorless rhizoidal tubers instead of the reddish or reddish brown ones as in C. surinamensis.
Bare soil, also base of trees and old pine stumps in wet acid meadows and swamp forests; 0--50 m; Fla., La., Miss.; South America (Argentina, se Brazil, Chile); w Europe; c and s Africa, Atlantic Islands (Azores, Madiera, s Iceland); Australia; Pactific Islands (New Zealand, New Caledonia); Asia (China).