1966] 



LEAFY HEPATICAE OF LATIN AMERICA — PART II 



181 



short, one or two cells thick. Female branches occasional, the bracts and brac- 

 teoles in three or four series, different from the leaves, orbicular-ovate, divided 

 above. Perianth to 6 cm long, cylindric to fusiform, of several layers of cells 

 below, one-layered above, the mouth contracted, crcnulate to long-ciliate. Shoot/ 

 sporophyte relationship a shoot-calyptra. Sporophyte stalk, the seta, with a 

 layer of 8-16 large cells surrounding 12 to 45 similar or smaller cells; capsule 

 spherical, with a 3- or 4-layered wall, the outermost layer with brown knot-like 

 thickenings along the radial walls, the innermost layer with brown bands across 

 the inner tangential wall; spores small, brown; elaters long, slender, bispiral. 

 Sporeling of the Nardia type. 



Type species: Jungermannia reptans L. 



This large genus is most abundant in the mountain forests of tropical and 

 subtropical regions, with a few species extending northward into the Northern 

 Hemisphere, or southward from the subtropics as in Bazzania. A few species 

 have an Antarctic distribution. 



Unlike Bazzania, this genus does not consist of obvious, well-marked groups 

 or sections, although differentiation has progressed along certain well-defined 

 lines. There is a high degree of variability among the plants of some species and 

 even between male and female plants of some species, so that limits of certain 

 taxa are arbitrary. 



Key to the Species 



1. Plants of tropical, subtropical, and warm temperate areas. 

 2. Plants very slender, filiform, appearing denuded ; leaves scale-like. 

 3. Stems irregularly branched, the branches very long, often dichotomous. 



2. L. subdichotoma. 

 3. Stems pinnately branched, the branches shorter, of limited growth. 

 4. Lateral branches mostly simple; leaves plane or nearly so. 



5. Leaves spreading, cuneate, the segments widely spreading; plants brown. 



1. L. patens. 



5. Leaves spreading, the segments tending to be connivent; plants brownish- 

 green. 4. L. portoricensis. 

 4. Lateral branches usually with several (often tufted) secondary branches; 

 stem leaves strongly concave, the segments incurved, touching the stem; 

 plants brownish. 3. L. incurvata. 

 2. Plants small to large; leaves larger, not scale-like; stems regularly pinnate to 

 bi- or tripinnate. 



3. Plants of small to medium size ; stems with leaves less than 0.8 mm broad. 

 4. Leaves very obliquely inserted, the line of attachment appearing to be nearly 

 longitudinal. 



5. Leaf segments long, the cells mostly 30-36 /*, quadrate, thin-walled. 



5. L. reptans. 



5. Leaf segments very short, widely divergent; leaves divided to one-fifth 

 of their length; leaf cells 14-19X14 m, the walls thickened; plants 

 turgid, whitish. 6. L. aequiloba. 



4. Leave less obliquely inserted, often subtransverse. 



5. Leaves conspicuously rectangular; segments long, straight, the cells 30-36 n, 



thin-walled. 5. L. reptans. 



5. Leaves not conspicuously rectangular, either cuneate, subquadrate or 

 truncate-ovate. 



6. Leaves cuneate, the segments widely divergent, plane or incurved. 

 7. Plants green to whitish; leaves usually widely spreading even when 



dry; leaf segments at least half the length of the leaf. 7. L. squarrosa. 



7. Plants greenish to brownish; leaves appressed when dry; leaf-segments 

 plane to incurved, long-triangular. 

 8. Bases of the leaf-segments mostb' four to six cells wide. 



