Monographs Details: Herberta M.Fleisch.
Authority: Fulford, Margaret H. 1963. Manual of the leafy Hepaticae of Latin America--Part I. Mem. New York Bot. Gard. 11: 1-172.
Description:Genus Description - Leafy plants yellowish to brown, often becoming reddish or purple, ascendent to erect, or pendent, from a prostrate rhizome (often obscure) with scalelike leaves; leafy stems of medium size or robust, to 30 cm long, or thin and delicate and very short, sparingly irregularly branched; branches rarely lateral, of the Frullania type, with the lanceolate half-leaf at the dorsal base, more frequently intercalary, from the axils of the underleaves or from the stem at the ventral base of the leaf or either side of the underleaf, leafy or flagelliform; stem in transverse section with a cortical band of one to three layers of cells with thick, deep brown to yellow walls, and a medulla of many larger cells with progressively thinner walls toward the middle, the pits numerous. Rhizoids thin-walled, from cells of the lower part of the underleaf or the scale-leaves of the flagelliform branches. Line of leaf insertion transverse. Leaves elongate to subquadrate, symmetric to asymmetric, deeply bifid (rarely trifid), the segments linear to lanceolate, the margins entire, serrate, toothed or appendiculate, especially near the base; vitta of narrow, elongate, thick-walled cells always present, bifurcating near the base of the leaf or just below the sinus, ending below the tips of the segments or in the tips; oil bodies four to eight per cell (at least in some species) round to oval, homogenous. Underleaves as large as the leaves, similar, symmetric. Plants dioicous. Male inflorescence terminal becoming intercalary on the stem, the bracts and bracteoles like the underleaves, pouched; antheridia large, spherical, usually in pairs in the axils of both the bracts and the bracteoles, the stalk of two rows of cells. Female inflorescence terminal on the leafy stem or long branch, with one or two subfloral innovations of unlimited growth, the inflorescence appearing to be on a short lateral or ventral branch, the bracts and bracteoles similar, in three to six series, increasing in size and degree of marginal serration from the leaves to the perianth, paraphyses often present among the bracts. Perianth fusiform, more or less 3-keeled, the third keel ventral, with three supplementary folds, divided to the middle into three bilobed (trilobed) divisions; slime papillae on the margins and surface of the segments. Shoot/sporophyte relationship a shoot-calyptra. Sporophyte capsule spherical, dark brown to black, the wall to 100 µ. thick, of five to seven layers of cells, the outer layer with characteristic red-brown knots on the outer radial walls, the innermost layer with half-rings on the inner tangential wall; elaters bispiral to the tips. Spores yellow to brown. Vegetative reproduction by means of leaf cladia from single dedifferentiated cells of old leaves and underleaves.
Discussion:Schisma Dumortier, Comm. Bot. 114. 1822.
Sendtnera C. G. Nees in G. L. & N. Syn. Hep. 238. 1844.
Type species: Jungcrmonnia juniperoidca Swartz.
The genus is readily recognized in the field because of its large size, habit, and the three rows of very similar, deeply bifid leaves and underleaves. For the most part, the species are more difficult to separate, since the most dependable diagnostic characters are microscopic.
There is considerable variation within any species, mostly in the size of the stems, the length of the leaves and underleaves, the number of appendages on the margins of the lamina of the leaves and underleaves, and the degree of thickening, but not the pattern, of the cell walls.
The genus is found primarily in elevated regions of the tropics but there is one species in Patagonia and several others in the Northern Hemisphere.