Jungermannia compressa Hooker
Plants with laterally compressed shoots 20 120 × 2 3 mm, erect or sub erect, forming thick mats or turfs, green to reddish brown or purplish, often appearing scorched. Stems fleshy, 250 360 µm in diameter, branches few, intercalary from distal stems; rhizoids few, colorless, often absent near stem apex. Leaves imbricate, erect appressed, orbicular to reniform, ca. 1 1.8 × 1.2 2.8 mm, with rounded, entire apices, slightly concave, shortly decurrent dorsally; median leaf cells 30 40 × 25 35 µm, marginal cells smaller, subquadrate, 18 25 µm; cuticle smooth; trigones distinct, small to large and bulging; oil bodies 1 3 per cell, ovoid to ellipsoid, 10 14 × 7 10 µm, shining, smooth, homogeneous or segmented with few segments. Underleaves spreading, small, up to 0.5 mm, subulate to lanceolate, most developed at shoot apices, often vestigial on lower part of stem. Sexual condition dioicous. Androecia terminal, becoming intercalary; bracts in 3 4 pairs, similar to leaves. Gynoecia terminal on main stems, bracts inserted on perigynium, larger and broader than leaves, reniform, exceeding length of perianth, hiding it; bracteole lanceolate, occasionally lobed, not connate to bracts; perianth conical, purplish, mouth crenulate; perigynium swollen, often purplish, continuous with stem, ca. 2 times longer than perianth. Sporophyte capsule brown; elaters 2 spiral. Spores 10 15 µm, slightly papillate, reddish brown.
Wet rocks along streams or in peaty bogs, Arctic alpine; s Greenland; B.C.; Alaska, Wash.; Europe; Asia; Atlantic Islands (Iceland).