1968] 



LEAFY HEPATICAE OF LATIN AMERICA PART III 



361 



slime papilla not parallel to the margin; cell-wall thin, the cuticle smooth. Under- 

 leaves of 2 adjacent cells, which may cut off rhizoid initials at the base. Plants 

 monoicous. Male inflorescence terminal or becoming intercalary on the stem or a 

 leafy branch, the bracts and bracteoles in up to 10 series, the bracts bifid, with a 

 lamina 4-6 cells wide, the bracteoles like the underleaves. Female inflorescence on 

 a short leafy branch, the bracts and bracteoles foliaceous, in 2 or 3 series, long, bifid 

 to one-half their length, the segments subulate. Perianth long, cylindrical below, 

 3-keeled above, the mouth of 6 slender lacineae. 



PI. 95. Fig. 2, a-c. 

 Habitat: On compact soil and on decaying wood in humid forests. 



PUERTO RICO: La Juanita, near Las Marias, E. G. Britton 3992 (NY). 

 BRAZIL: S. Gabriel, Spruce, Hep. Sprue. (NY); fl. Negro, cataracts, Spruce, Hep. Sprue. 

 (isotype NY); S. Gabriel and Panure, Spruce, Hep. Sprue. (BM, G-13418, NY). 



Arachniopsis Spruce, On Ccphalozia 84. 1882. 



Plants very small, confervoid, whitish, yellowish or bluish green; stems thread- 

 like, 1-3 cm long, sometimes becoming flagelliform at the tips, often branched; 

 branches ventral-intercalary, in the axils of the underleaves, leafy or more rarely 

 flagelliform, or short leafy and bearing a female or occasionally a male inflorescence. 

 Rhizoids slender, from the cells of the underleaves. Line of leaf insertion subtransverse 

 or oblique with the leaves succubous. Leaves of one or a pair of filiform, uniseriate 

 segments 4-6 or more cells long, the tip cell short. Underleaves usually of 2 adjacent 

 cells capped with slime papillae. Plants monoicous and dioicous. Male inflorescence 

 terminal on a stem or leafy branch, the bracts similar to the leaves, monandrous, 

 the bracteoles similar to the underleaves. Female inflorescence terminal on a short 

 branch, the bracts and bracteoles in 3-5 series, with a lamina and long segments, 

 the outer series bifid, the inner series largest, quadrifid. Perianth cylindrical below, 

 with 3 rounded keels above, the mouth laciniate with 12 long lacineae. Regeneration 

 from the tip or upper cells of the leaf. Sporophyte not seen. 



Type species: lectotype Jungermannia diacantha Montagne, 1856. 



Key to the Species 



1. All leaves of a plant of 1 row of 3-5 cells. 3. A. pecten. 

 1. Leaves of a pair of uniseriate segments free to the base (here and there only one segment 

 may develop). 



2. The pair of leaf segments flattened, parallel, one above the other. 4. A. dissotricha. 



2. Segments of a pair arising at almost the same level, widely spreading, slender, 6-10 

 cells long. 



3. Leaf segments mostly flaccid; cells 78-90 m X 20-26 /x. 2. A. coactilis. 



3. Leaf segments often stiff and bristle-like; cells mostly 130 X 20 /i. 1. A. diacantha. 



1. Arachniopsis diacantha (Montagne) Howe, Bull. Torrey Club. 29: 288. 1902. 



Jungermannia diacantha Montagne, Ann. Sci. Nat. IV. Bot. 5: 349. 1856. 

 Arachniopsis coactilis var. capillacea Spruce, On Cephalozia 85. 1882. 

 Arachniopsis capillacea Spruce, ms. Hep. Sprue. 



Portion of a "flagelliform" branch, a reversion similar to the adult stage of R. monodactylus, 

 X 200. 1 n. Underleaf with two rows of cells, X 200. Drawn from isotypes, Spruce, Hep. Sprue. 

 (NY). 



Fig. 2. R. monodactylus. 2 a. Stem, dorsal view, X 200. 2 b. Underleaf on a stem, X 200. 

 2 c. Tip of a perianth segment. Drawn from an isotype, Spruce, Hep. Sprue. (NY). 



