American Species of Marchantia. 299 



unknown among American species, where the involucres and 

 sporophytes invariably alternate with the lobes. Since there are 

 apparently no specimens of Plumier's plant in herbaria, it is 

 clear that M. chenopoda L. represents an unidentifiable plant, 

 and the logical course would be to give up the species altogether. 



In the literature of the Hepaticae, however, M. chenopoda 

 has an established place, and it seems justifiable to interpret it 

 according to the descriptions of later writers. Even Plumier's 

 figure gives us a little help because it shows that he occasionally 

 observed a five-lobed receptacle, although he makes no mention 

 of such a structure in his text. Since most subsequent writers 

 ascribe to the species definitely a five-lobed receptacle, and since 

 the species to which they assign the name is abundant in 

 Martinique, it is quite probable that their M. chenopoda is the 

 same as Plumier's plant. Unfortunately their descriptions and 

 figures are not without discrepancies, and it becomes evident that 

 Taylor at least did not distinguish between what is here called 

 M. chenopoda and M. domingensis. 



Apparently Swartz^^ was the first to describe the male recep- 

 tacles. He states that they are subpeltate, unsymmetrical, pal- 

 mate-quadrifid, plane and verruculose above (like the thallus), 

 and convex below, the rays or lobes being linear, obtuse, and 

 often unequal, with membranous, undulate margins. He cites no 

 stations for the species although he implies that it occurs in 

 Jamaica. Quadrifid receptacles are sometimes found in M. 

 domingensis, but it is probable that Swartz had the true M. cheno- 

 poda before him, and his description is definitely cited in tlie 

 Synopsis Hepaticarum. 



Schwaegrichen,*^ in 1814, quotes M. chenopoda from Africa 

 as well as from America, and F. Weber,'** the following year, 

 notes a similar extension of range. Neither writer adds anything 

 significant to our knowledge of the species, and it is probable 

 that their citation of African stations is based on incorrect deter- 

 minations, since all subsequent writers restrict the range of 

 M. chenopoda to America. 



A few years later Raddi*^ extended the known range of the 



*" Fl. Ind. Occid. 1880. Erlangen, 1806. 



^ Hist. Muse. Hepat. Prodr. 32. Leipzig, 1814. 



"Hist. Muse. Hepat. Prodr. 103. Kiel, 1815. 



^ Mem. Soe. Ital. Modena 19 : 44- 1823 ; 20 : pi. 6a, f. i, 2. 1829. 



Trans. Conn. Acad., Vol. XXI 21 1917 



