Two species of Pottiaceae are described from Mexico: Scopelophila norrisii sp. nov. and Tortula eckeliae sp. nov. The proposed Moss Flora of Mexico, organized by Dr. A. J. Sharp, has lent impetus to study of the mosses of this highly interesting area. While working through unidentified collections from TENN, I found a particularly interesting new species of Scopelophila (Mitt.) Lindb. Scopelophila norrisii sp. nov. (Fig. 1-6) Plantae tagetes tenues formantes, supra virides usque luteo-virides, infra brunneolae, costa foliorum nigrescente instructae. Caules leniter radiculosi, interdum ramificantes, filo centrale carentes. Folia in statu sicco incurva crispataque, in madido late patentia, anguste spathulata, pagina adaxiali trans folium late canaliculata, marginibus planis circa apicem integris usque leniter serrulatis, apice acuto interdum late apiculato instructa. Costa percurrens vel 1-4 cellulas sub apicem evadens, cellulis ducium 2 in strato unico, filo hydroideo nullo, strato stereidarum unico instructa. Cellulae laminares supernae rotundo-quadratae usque hexagonae, laeves, adaxialiter tumescentes, abaxialiter planae vel laxe convexae, secus margines in 3-seriebus parietibus crassis instructae; basales medialiter distinctae, rectangulato-tumescentes, hyalinae. Dioicae; perichaetia terminalia, foliis internis haud distinctis instructa; perigonia terminalia, foliis internis laxe vaginantibus. Seta infra leniter torta; theca brunnea, in sicco laevis, brevi-elliptica, collo subdistincto et cellulis exothecii rectangulatis et parietibus tenuibus instructa; annulus leniter differens, e cellulis parvis compositus; peristomium nullum. Sporae brunescentes, admodum laeves. Plants in a thin turf, green to yellow-green above, tan below, costa blackish. Stems weakly radiculose, occasionally branching, 1.0-2.5 mm long, pentagonal in transverse section, central strand absent, cells large, homogeneous in size, cortex with somewhat thicker walls, epidermis undifferentiated. Axillary hairs uniseriate, ca. 4-5 cells in length, basal cell brownish. Leaves incurved and curled when dry, wide-spreading when moist, narrowly spathulate, 1.7-2.2 mm long, adaxial surface broadly channelled across leaf, margins plane, entire to weakly serrulate above, apex acute, sometimes broadly apiculate, base scarcely differentiated to becoming broader below a wasp waist. Costa percurrent to ending 1-4 cells below apex, adaxial epidermal cells quadrate, smooth, 3-4 across the costa, abaxial epidermal cells elongate, smooth; transverse section of costa round, adaxial surface weakly bulging, adaxial epidermal cells in one layer, adaxial stereid band lacking, guide cells 2 in 1 layer, hydroid stand absent, abaxial stereid band strong, abaxial epidermal cells well differentiated, in one layer, lumina oval. Upper laminal cells rounded-quadrate to hexagonal, 8-10(13) im wide, 1:1, smooth, walls evenly thickened, adaxially bulging, abaxially flat to weakly onvex, thicker walled in three rows along leaf margins; basal laminal cells differentiated medially in lower /5 of leaf, bulging rectangular, to 30 jtm wide, 2:1, hyaline. Dioicous; perichaetia terminal, inner leaves scarcely differentiated; perigonia terminal, not gemmate, inner leaves loosely sheathing, prosenchymatous, deltoid, paraphyses absent. Seta 2.5-3.4 mm long, one per perichaetium, brown, twisted weakly clockwise below; theca 0.6-0.8 mm long, brown, smooth when dry, short-elliptical, neck weakly differentiated, macrostomous; exothecial cells rectangular, 15-20(25) jim wide, 2-3:1, walls thin; stomates present on neck, phaneropore; annulus weakly differentiated, of small cells; peristome lacking; operculum and calyptra not seen. Spores light brown, essentially smooth, 8-10 tm in diam. Laminal color in 2% KOH solution: deep yellow-