American Species of Marchantia. 



239 



Fig. 2. Marchantia polymorpha L, 



Anatomical details. A, B, Epidermal pores of thallus, surface view, 

 X 225. C. Pore in cross-section, x 225. D-L Inner openings of pores, 

 X 225. J. Marginal portion of thallus, in section, showing two epidermal 

 papillae, x 225. K. Stalk of male receptacle, cross-section near base, 

 X 40. L. Female receptacle, section of part of disc, showing a pore and 

 three epidermal papillae, x 225. M. Part of involucre, x 50. N. Part 

 of cupule, showing three lobes, x 50. O, P. Epidermal papillae from 

 cupule, in section, x 225. A, D. Opdal, Norway, /. Hagen, in V. Schiff- 

 ner's Hep. Europ. Exsic. 15, type of var. mamillata Hagen. B, I, J. 

 Jamaica, A. W. Evans. C. Oaxaca, E. W. Nelson 2530. E, L-P. New 

 Haven, Connecticut, G. E. Nichols, A. W. Evans. F-H. Wilbraham, 

 Massachusetts, E. A. Chapin, G and H representing forma aquatica. K. 

 Eberswalde, Germany, A. W. Evans. 



