178 THE VOYAGE OF H.M.S. CHALLENGER. 



Asterella hemisphaerica, Beauv. 



Astertl/a Ifmiaplarrku, Beauv. in Diet, Sc. Nat, iii. p. 258; Mitt, in Jcmrn. Linn. Soc. Lond., xv. 



p. 65. 

 Eeboulia hemisphcerica, Eaddi ; G. L. N., Synop. Hepat., p. 548. 



Tristan da Cunha. — Imperfectly fruited specimens — Moseley. 

 A very widely diffused plant. 



Marchantia polymorpha, Linn. 



Marchantia polymorpha, Linn., Sp. PI., ed. 2, p. 1G03; G. L. N., Synop. Hepat., p. 522; Taylor in 

 Hook. Lond. Journ. Bot., 1844, p. 400. 



Tristan da Cunha. Moseley. 

 Almost cosmopolitan. 



Anthoceros plicatus, Mitt. 



Anthoceros plicatus, Mitt, n. sp., in Journ. Linn. Soc. Lond., xv. p. 65. : 



Frondes procumbentes, lobati, planiusculi, marginibus iucurvis squamulis minutis 

 limbatis ; iuvolucrum apice dilatatum, infundibuliforme, fructus brevis, decurvus, plicis 

 longitudinalibus striatus. — Anthoceros Icevis, Mitt, in Journ. Linn. Soc. Lond., xv. p. 65, 

 non Linn. 



Frondes 2-3mm. lati, post exsiccationem atrati. Fructus cum involucro 2-3mm. longus. 



Tristan da Cunha. — Endemic. Growing on the ground in the same manner as 

 Anthoceros Icevis — Moseley. 



The greater portion of the specimen of this species is without fruit, but on a small 

 piece a few rather young fruits have been found. These resemble the similar parts of the 

 genus Notothylas, but they show a distinct involucre as usual in Anthoceros ; the fruit itself 

 is distinctly plicate, but too young to show in what manner it opens, and the spores are 

 not fully formed. The margin of the fronds appears to have the very small scales as if in 

 several rows. 



Thouars (Esquisse Fl. Trist., pp. 27-30) enumerates eleven Hepatic* and twenty-three 

 Musci, most of which are clearly the same as those collected by later travellers, whilst the 

 rest are doubtful. We are not aware that Thouars's collection was ever revised. 



LIOHENES. 

 LICHENACEI. 



Stereocaulei. 

 Stereocaulon mixtum, Nyl. 



Stereocaulon mixtum, Kyi., Synop. Lich., i. p. 238 ; Crorubie in Journ. Linn. Soc. Lond., xvi. p. 222. 



Tristan da Cunha. Moseley. 



West Indies ; Mexico ; New Grenada ; Bolivia ; Sandwich Islands. 



