227 



pits are narrow. In Leiicolejeunea, on the contrary, there is no 

 pigmentation, the hyahne papilla is borne at the distal base of 

 the apical tooth, the trigones are small, the intermediate thicken- 

 ings are few and far between (except sometimes at the base of 

 the lobe), and the pits are wide. The antheridial spikes in 

 Arcliilejeuiiea are terminal or intercalary on leading branches 

 and the bracteoles are borne throughout their entire length, 

 while in LeiLcolejetmea the spikes occupy short branches and the 

 bracteoles are limited to the base. In both genera the leaves 

 are rounded to very obtuse at the apex, the underleaves are 

 undivided, the female branch bears one or two subfloral innova- 

 tions, and the perianth is five-keeled. 



It is probable that Leiicolejciinea, in spite of its undivided un- 

 derleaves, bears a certain relationship to the genera Cheilolejciinea 

 and Pycnolcjewica of the Lejeuneae Schizostipae. In some cases 

 it resembles them so strongly in habit and general appearance 

 that it is difficult to distinguish it from them in the field. It dif- 

 fers from Cheiiolejewica in its five-keeled perianth and in the 

 structure of the lobule, the hyaline papilla although distal being 

 displaced into the sinus. In Pycnolcjeiinea the papilla is proxi- 

 mal in position. 



In addition to the three species already mentioned, Lejeunea 

 xanthocarpa Lehm. & Lindenb. and Lejeunea rotiindistipiila 

 Lindenb. may be safely referred to Leucolejcimea. The genus is 

 most at home in the tropics, but its range extends well into tem- 

 perate regions. The first species given below may be designated 

 the type of the genus. 



Leucolejeunea clypeata (Schwein.) 



Jiingermannia clypeata Schwein. Spec. Fl. Amer. Sept. Crypt. 



Hep. 12. 1 82 1. 

 Lejeunea clypeata SuUiv. in Gray, Manual, Ed. I. 685. 1848. 

 Archilejeunea clypeata Schiffn. in Engler & Prantl, Nat. Pflanzen- 



fam. i^ : 130. 1895. 



On rocks and trees. Massachusetts and New York, south to 

 Georp-ia and Louisiana. 



