American Species of Marchantia. 



279 



observed by the writer. The nearest approach to an entire con- 

 dition is seen in Fig. 12, E, although even here the margin is 

 distinctly and closely crenulate; in Fig. 12, F, the crenulate con- 

 dition is more pronounced, some of the teeth being two cells long ; 

 in Fig. 12, G, a crenulate portion directly adjoins a short-ciliate 

 portion, in which the cilia are two or three cells long ; in Fig. 



Fjg. 12. Marchantia domingensis Lehm. & Lindenb. 



Anatomical details. A. Stalk of male receptacle, cross-section, x 40. 

 B-D. Stalks of female receptacles, cross-sections, x 40. C having been 

 cut near base. E-J. Parts of involucres, x 100: H and I were dissected 

 from a single involucre; J, from another involucre on the same recep- 

 tacle. K. Part of cupule, x 100. A. Florida, A''. L. T. Nelson 47. B, F. 

 Texas, F. D. Heald. C, H-J. Jamaica, E. G. Britton 668. D. St. Kitts, 

 Britton & Cowell 626. E. Alabama, Earle & Baker 52. G. Guatemala, 

 Cook & Griggs 82. K. Cokely, Jamaica, IV. Harris. 



12, H-J, taken from a single receptacle, the variation to be 

 expected is shown wnth especial clearness, some of the margmal 

 teeth or cilia being straight and some curved. In all probability 

 the laciniate and fimbriate involucres of the descriptions have 

 been the result of irregular tears in old material. 



In the case of the male receptacle, Sullivant states that the 

 number of lobes in M. disjuncta is normally seven, although some 



