American Species of Marchantia. 309 



Fig. 20. Marchantia chenopoda L. 



Anatomical details. A. Cells from compact ventral tissue in cross- 

 section, including two sclerotic cells and a cell containing oil-bodies, x lOO. 

 B. Cells from same tissue in longitudinal section, including a sclerotic 

 cell, X 100. C-E. Cells from basal portions of median scales, x lOO. 

 F. Stalk of male receptacle, cross-section, x 50. G-L Stalks of female 

 receptacles, cross-sections, x 50: G, showing a stalk of average size; H, 

 a slender stalk near the middle; and I, the same slender stalk near the 

 base. J-M. Portions of involucres : J, x 40 ; L-M, x 100. A-G, J. 

 Jamaica, A. W. Evans 405, W. R. Maxon 880. H, I. Panama, R. S. 

 Williams 1084. K. Vera Cruz, Barnes & Land 631. L. Costa Rica, 

 Cook & Doyle 301. M. Bolivia, R. S. Williams 2143. 



