Monographs Details: Archilejeunea bischleriana Gradst.
Authority: Gradstein, S. Robbert. 1994. Lejeuneaceae: Ptychantheae, Brachiolejeuneae. Fl. Neotrop. Monogr. 62: 216. (Published by NYBG Press)
Synonyms:Archilejeunea auberiana (Mont.) Steph.
Description:Species Description - Autoicous, copiously fertile. Plants 1.5-3 cm long × 1.5 mm wide, glossy green to brown green, not becoming black, creeping to ascending to erect on twigs. Stems in cross section on average composed of 12-14 epidermal cells surrounding 25 smaller medullary cells, epidermis cells subrectangular, 25-30 × 18-25 µm, medullary cells 13-20 µm in diam., all cell walls slightly thickened; ventral merophyte four cell rows wide. Leaves ± imbricate, dorsal lobe ovate-oblong, ca. 0.75 × 0.5 mm, apex rounded, plane, margins plane or slightly recurved, ventral margin curved, forming an angle of ca. 120° with the keel; median cells about 25-40 µm in largest diam., trigones small, simple or irregularly radiate, intermediate thickenings scarce, 0-1 per wall; oil bodies coarsely segmented, 3-7 in median leaf cells. Lobules almost invariably well-developed (a few reduced lobules may be present at branch bases and on innovations), short rectangular, ca. 1/3 x lobe length, apex truncate, with one sharp, 2 cells long, outwardly pointing tooth, free margin weakly bordered by elongated, thin-walled cells. Underleaves distant, small, reniform, 2-3 × stem width, apex truncate, margins plane. Androecia terminating elongated vegetative branches or occupying specialized branches, bracts in 4-10 series, bracteoles distinctly smaller than underleaves, becoming almost reduced near the apex of the spike. Gynoecia with only one lejeuneoid innovation, sometimes with an additional "pseudo-innovation" of the Lejeunea-type, innovations usually repeatedly fertile, bracts smaller than leaves, suberect, with reduced lobules; bracteole elongated, rather small, about 1/4-1/3 × perianth length. Perianths long exserted, cylindrical-obpyriform, short-stalked at base, ca. 1.2 mm long, 5-keeled over most of their length, the keels narrowly winged and crenulate, apex truncate; beak short, 3-4 cells long. Sporophyte not observed.

Discussion:Archilejeunea bischleriana is named in honor of Dr. Helene Bischler, Paris who first collected the species. The species shows affinities to both A. auberiana and A. parviflora but is different from either of them. The outstanding characters of A. bischleriana are the small, truncate lobules, which show hardly any tendency for reduction and have one sharp tooth and a more or less bordered free margin, and small, reniform underleaves. Unlike the other species of the subgenus Dibrachiella, innovations in Archilejeunea bischleriana are invariably singly.

With A. parviflora the species shares occurrence in the shaded understory of moist forests, although those in which A. bischleriana grows are considerably wetter than any of the forests in which A. parviflora has been found. The species also shares with A. parviflora the somewhat enlarged stem epidermis, a character unusual for Archilejeunea. In other respects (lobules, underleaves) the two species are quite different, however.
Distribution:Colombia South America| Chocó Colombia South America|