Mylia Gray, Nat. Arr. Brit. Pl. 1:693. 1821.
[as Mylius; named for Willem Mylius, a Dutch physician]
Marie L. Hicks
Plants simple or sparingly branched, prostrate or decumbent with ascending apices when crowded, forming loose mats or thick tufts, green to reddish brown. Stems rather fleshy, 450 600 µm in diameter; branching mostly terminal or lateral and axillary; cortical and medullary cells not distinctly differentiated; rhizoids scattered over ventral stem surface, long, often dense, especially at leaf and underleaf bases. Leaves succubous oblique, alternate, circular to ovate in outline; leaf cells irregularly hexagonal, large, ca. 45 55 µm in diameter, with large, bulging trigones and thin intervening walls; oil bodies granular botryoidal, opaque, or hyaline. Underleaves present, lanceolate. Specialized asexual propagation by gemmae on leaf margins, ovate to elliptical, 1 2-celled. Sexual condition dioecious. Androecia intercalary; bracts imbricate, similar to leaves, with saccate base; antheridia 1 3 per bract with large jacket cells; stalk 1 seriate, long. Gynoecia terminal on main shoot; bracts sub orbicular, entire, larger than leaves, partially enclosing the perianth; bracteole present, lanceolate; perianth exerted about 1/4 1/2 above bracts, inflated, laterally compressed, the mouth wide, truncate, entire to ciliate; perigynium not present. Seta ca. 9 11 cells in diameter. Capsule short ovoid, 4 valved; walls 3 5 cells thick, exterior layer with thickenings that extend inward, the interior layers with semiannular thickenings; elaters 120 160 ´ 8 10 µm, 2 spiral. Spores 15 20 µm.
Species 4 (2 in the flora): North America, Europe and Asia.
SELECTED REFERENCES
Schuster, R.M. 1969. The Hepaticae and Anthocerotae of North America. New York.
