18 Evans: HEpATICAE OF PUERTO Rico - 
strated by Spruce. It is made up of two very distinct sections, 
one characterized by undivided underleaves, the other by bifid 
underleaves. Spruce considered both of these sections subgeneric 
in value and included them under the comprehensive genus 
Lejeunea. For the first he reserved the name Omphalanthus, 
changing it to Omphalo-Leeunea for the sake of consistency. 
The species included under the second section he transferred to 
his subgenus Zaxi-Lejeunca. This disposition of the matter has 
been followed by subsequent writers, including Schiffner, who 
raised both these subgenera to generic rank. In doing this, how- 
ever, he discarded the name Omphalo-Lejeunea and restored the 
original name Omphalanthus. 
As thus restricted the genus consists of a single variable 
species, O. filiformis, which has a very wide distribution in the 
American tropics. This species may be described as follows: 
OMPHALANTHUS FILIFORMIS (Swartz) Nees : 
Jungermannia filiformis Swartz, Prodr. Fl. Ind. Occ. 144. 1788. : 
Jungermannia birotunda Ehrh. Beitr. 4: 45. 1789. 
Jungermannia geminiflora Nees, in Martius, Fl. Bras. 1°: 354. 
Phragmicoma filiformis Nees, Naturg. Eur. Leberm. 3: 248. 
1838. 4 
Lejeunea filiformis Nees, in Montagne, Flor. Boliv. 64; d Orbigny, ~ 
Voy. dans l’Amér. Mérid. 7°. 1839. : 
Lejeunea geminifiora Nees, /. c. 66. 1839. 
Omphalanthus geminifiorus Nees, in G. L. & N. Syn. Hep. 303- 
1845. 
Omphalanthus filiformis Nees, ¢. c. 304. 1845. 
Lejeunea tenuifolia Tayl. Lond. Jour. Bot. 5: 391. 1846. 
Lejeunea (Omphalo-Lejeunea) filiformis Spruce, Hep. Amaz. et | 
And. 87. 1884. : 
Pale yellowish-green, becoming brownish with age, growing in 
loose tufts : stems erect or ascending, with few rhizoids, 0.15 mm. — 
in diameter, sparingly and irregularly branched, the branches ob-— 
liquely to widely spreading, with smaller leaves than the stem but — 
never microphyllous : leaves imbricated, the lobe attached by an 
almost longitudinal line, abruptly dilated from a narrow base, the 
inflated portion orbicular, 0.7 mm. long, convex and sometimes — 
