Evans: HEpaTIcAE OF PuERtTo RIco 537 
longer branch and is normally destitute of an innovation, the bracts 
are as large as the vegetative leaves or larger, and the male spikes 
bear bracteoles throughout their entire length. Odontolejeunea 
differs from Symdiezidium in its dentate leaves and underleaves, in 
its denticulate lobules, and in its longer female branch with large 
bracts. 
Four species of Symbiesidinm have been reported from Puerto 
Rico, two by Hampe and Gottsche from the collections of Schwan- 
ecke, and two others by Stephani from the collections of Sintenis. 
Of these four species only two occur in the material studied by 
the writer. These two species are described and figured in the 
present paper, and attention is called to the other two species. 
SYMBIEZIDIUM TRANSVERSALE (Swartz) Trevis. 
Jungermannia transversalis Swartz, Prodr. Fl. Ind. Occ. 144. 
1788. 
Phragmicoma transversalis Nees, Naturg. Europ. Leberm. 3: 248. 
1838. 
Lyeunea transversalis Nees; G. L. & N. Syn. Hep. 310. 1845 
(excluding § and r)- 
Symbiezidium transversale Trevis. Mem, Ist. Lomb. II. 4: 403. 
1877, 
Lejeunea (Platy-Lejeunea) transversalis Spruce, Hep. Amaz. et 
And. 124. 1884. 
P latylejeunea transversalis Schiffn. ; Engler & Prantl, Nat. Pflan- 
zenfam. 1°: 13h. 1895. 
Brownish- or yellowish-green, rarely bright-green, slightly 
glossy, at first scattered but afterwards forming depressed mats of 
considerable extent : stems prostrate, loosely adherent to the sub- 
stratum, 0.25 mm. in diameter, at first simple or sparingly branched, 
becoming copiously and irregularly pinnate with age, the branches 
Prostrate, similar to the stem but with somewhat smaller leaves, 
hot microphyllous : leaves imbricated, the lobe widely spreading, 
alcate, ovate, on robust stems from 1.5-2 mm. long, 1.2 mm. wide, 
rounded to slightly cordate at the base and arching across or a 
little beyond the axis, antical margin slightly outwardly curved to 
the broad and rounded apex, postical margin incurved near keel 
and forming with it a rounded or obtuse angle; lobule ovate or 
®vate-lanceolate in general outline, 0.45 mm. long, 0.2 mm. wide, 
strongly inflated in the basal half; cells of lobe averaging 25 at 
