Evans: Hepaticae of Puerto Rico 19 



Even in a sterile condition, there is no Puerto Rico species 

 with which C. lineata is likely to be confused. Its comparatively 

 large size, its convex lobes with blunt apices, its peculiar lobules, 

 its convex leaf- cells with large trigones, its small underleaves, bifid 

 and with sharp divisions, will all serve to distinguish it. Fruiting 

 specimens are further distinguished by the beakless and flattened 

 perianth borne on a short and simple branch. 



t 



PYCNOLEJEUNEA 



The characters which have been relied upon in separating Bye* 

 nolejeunea from Cheilolejeunea are the robustness of the plants, the 

 closely imbricated leaves, the elongated lobules, the large under- 

 leaves and the five-keeled perianth. All of these characters, with 

 the exception of that drawn from the lobules, are fairly constant 

 and will usually serve to distinguish the genus not only from 

 . Cheilolejeunea, but also from Rectolejeunea. The lobule, however, 

 varies greatly in length and is sometimes scarcely longer than 

 broad. In the structure of the apical tooth and in the position of 



the hyaline papilla the lobule agrees with that found in Rectole- 

 jennea. 







The selection of the type species of Pycnolejennea is beset with 

 the same difficulties as in Cheilolejeunea. The first species men- 

 tioned by Spruce is Z. contigna Nees ; * the first species which he 

 describes is also called L. contigna, but the specimens from which 

 this description is drawn are now recognized as the type of Pycno-> 

 lejeimea Sprnceana Schiffn. ; f the first species which Schiffner lists 

 is P. macroloba (Mont.) Schiffn. % Under the circumstances the 

 writer suggests that P. Sprnceana be considered the type, since 

 this is really the first species which Spruce describes. 



Pycnolejeunea is confined to tropical and subtropical regions. 

 It attains its highest development in the East Indies and neigh- 

 boring islands, but has numerous representatives in America. At 

 the present time only one species is definitely known from Puerto 

 Rico. Most if not all of the species grow on bark, sometimes in 

 pure mats, sometimes in admixture with other hepatics. 



*Hep. Amaz. et And. 247. 1884. 



fBot. Jahrb. 23: 583. 1897. 



JEngler & Prantl, Nat. Pflanzenfam. i 3 : 124. 1893 { = Lejmnea macroloba 



Mont. Ann. Sci. Nat. Bot. II. 19: 260. 1843). 



