Micropterygium

Authority

Fulford, Margaret H. 1966. Manual of the leafy Hepaticae of Latin America--Part II. Mem. New York Bot. Gard. 11: 173-276.

Family

Lepidoziaceae

Scientific Name

Micropterygium

Description

Species Description - Leafy stems ascendent to erect from a prostrate, branched rhizome system, whitish to green, becoming light or dark brown, in mats or scattered among other bryophytes; stems simple or irregularly branched, the branches axillary, intercalary, lateral branches leafy, ventral branches leafy or flagelliform; in transverse section the stem with a cortical layer of 12 rows of slightly larger cells with thick, light to dark brown walls surrounding the medulla of usually colorless cells with thinner walls. Rhizome radial, with three rows of scale-leaves, branched, the branches intercalary, like the rhizome, or flagelliform, or erect radial, with three rows of small orbicular leaves and eventually becoming leafy, or leafy from the beginning. Rhizoids branched at the tijis, colorless to brown, on the scale-leaves of the rhizome and the flagelliform branches. Line of leaf insertion transverse to slightly oblique, attached to four cells of the stem, the leaves eciuitant-imbricatc. Leaves orbicular, broadly ovate, lanceolate to subrectangular in outline, concave to complicate, the keel broad to sharply acute, a ventral wing from the keel absent or rudimentary, to large, three to five cells wide and extending from the apex to the middle of the leaf or beyond (in one species the wings in pairs), the lobes equal or the dorsal lobe larger, the margins entire, crenulate, serrate, dentate or incised; the cell surface (ventral) plane, or convex, or with a conspicuous mamillose projection, the cuticle smooth, verruculose, papillose or rough-warty. Underleaves similar to the leaves, or smaller, orbicular, ovate, long oval, quadrate, or of only a few cells, in some species showing a decrease in size from the base of the stem to the tip. Plants dioicous, the sexual branches ventral from near the base of the leafy stem, more rarely from the rhrizome. Male inflorescence slender, short (very rarely terminal on the stem), usually catkin-like, hyaline, the bracts and bracteoles in four to ten series, smaller than the leaves and underleaves, the bracts concave, inflated, the bracteoles, small ovate, plane; antheridia one or two, in the axils of the bracts. Female inflorescence on a short sexual branch, without innovations, the bracts and bracteoles similar, in 3-4 series, different from the leaves, long ovate to ovate-lanceolate, toothed to laciniate-ciliate above. Perianth 4-6 mm long, terete below, trigonous and often with additional lobes above, the mouth contracted, three-parted and fringed with numerous cilia or ciliate laciniae Sporophyte capsule, long, red-brown. Spores small, red-brown.

Discussion

Type species: Jungermannia carinata Greville, Ann. Lye. Nat. Hist. N.Y. 1: 276. 1825.

Distribution

The genus is abundant in wet forests of tropical South America and extends southward into southern Brazil and northward into the West Indies. I have seen no specimens from Central America. Some of the species are restricted locally while others are widespread with seemingly several subspecies or varieties with distribution patterns which apparently overlap to some degree. Except for those species in which the stems with leaves tend to be radial the genus is readily recognized by the folded, flat

South America| West Indies|