1968] 



LEAFY HEPATICAE OF LATIN AMERICA PART III 



375 



attached — 2 + 2 lateral, and 4 on the convex ventral side) surrounding a medulla 

 of smaller cells. Branches frequent, occasionally lateral of the Frullania type (the 

 thallus "forking"), more frequently ventral-intercalary, axillary, thalloid, or flagel- 

 liform, or foliate-sexual. Rhizoids in tufts associated with the underleaves or in 

 discrete tufts in three rows on the flagelliform branches. Wings formed from leaves 

 fused edge to edge along the lateral margins, more rarely fused only part way, the 

 succubous habit sometimes evident. Underleaves reduced to a few cells, 2, 4, 6 or 8 

 cells wide, 1-3 cells high. Plants monoicous or dioicous, the inflorescences foliaceous. 

 Male inflorescence long spicate, terminal on a flagelliform tip of the thallus or as a 

 ventral sexual branch; bracts bifid, monandrous, bracteoles few-celled. Female 

 inflorescence on a short ventral branch, the bracts and bracteoles in 3 series, the 

 innermost series largest, bifid. Perianth cylindrical below, 3-keeled above, the mouth 

 3-lobed, 6-laciniate. Shoot-sporophyte relationship a shoot-calyptra with unfertilized 

 archegonia to near the apex. Capsule small, oblong in outline, the wall 2-layered; 

 seta in transverse section, of 8 large outer cells surrounding 4 similar cells. 

 Type species: Pteropsiella frondijormis Spruce, 1876. 



Key to the Species 



Margins of the thallus conspicuously serrate; cells of the outer 1 or 2 rows smaller 



than those of the rest of the wing. 2. P. serrulata. 



Margins of the thallus entire or with an occasional several-celled tooth; marginal 



cells scarcely different from those of the rest of the wing. 1. P. frondijormis. 



1. Pteropsiella frondiformis Spruce, Jour. Bot. London 14: 161. 1876. 

 Cephalozia subg. Pteropsiella, frondijormis Spruce, On Cephalosia 25. 1882. 



Thallus prostrate, olive-green to dark green, 1-3 cm long, 3-5 mm wide, the 

 axis flattened dorsally, of 2 cortical rows of large cells between the 2 broad uni- 

 stratose wings, sometimes becoming flagelliform at the tip; branches occasionally 

 lateral, of the Frullania type (the thallus "forked"), usually ventral-intercalary, in 

 the axils of the minute underleaves, forming a winged thallus, or a flagelliform or 

 a sexual branch. Rhizoids from the base of the few-celled underleaves. Wing margin 

 straight or occasionally incised or with 1- to 3-celled irregular teeth, these then 

 bearing the "slime" papillae; papillae elongate parallel to the margin, mostly 160 X 

 10-17 /a; cells of the wing quadrate to rectangular in outline, 34-75 X 30-40 /x, 

 the marginal row not essentially different, the walls thin, without trigones, the cuticle 

 faintly verruculose. Underleaves 2-4 cells across, one to a few cells high. Plants 

 dioicous. Male inflorescence foliaceous, long, spike-like, leafy, ventral or terminal 

 on the winged thallus, the bracts in 2 rows, in 8-12 series, bifid or retuse, the bracte- 

 oles few-celled. Female inflorescence foliaceous, on a short sexual branch, the bracts 

 and bracteoles large, bifid, the segments incised. Perianth long, cylindrical below, 

 with three rounded keels above, the mouth ciliate-laciniate. 



PI. 102. Fig. 1, a-i. 



Habitat: On moist river banks, sandy flats and decaying bark and wood in 

 shaded areas. 



VENEZUELA: Bolivar: near Salto de Pacairao, 1220 m, Steyermark 60485 (F). 

 BRAZIL: San Gabriel et San Carlos, Spruce, Hep. Sprue, (isotypes G, NY). 



margin of smaller cells and scattered long papillae, X 200. 2 c. Terminal male inflorescence, X SO. 

 2 d. Segment from the mouth of the perianth, X 200. Drawn from an isotype, Spruce, Hep. 

 Sprue. (NY). 



