﻿Evans: The genus Plagiochasma 261 



perhaps justifiable, both spellings having been used by the original 

 authors. In 1874, Dumortier (7, p. 148) discarded both Plagio- 

 chasma and Aytonia and applied the name Otiona of Corda to the 

 genus. In 1877 Trevisan (39, p. 436) revived the name Rupinia 

 of the younger Linnaeus. In 1894 Le Jolis (19, pp. 109-116) gave 

 excellent reasons for discarding the names Aytonia, Otiona, and 

 Rupinia, and for retaining the name Plagiochasma. This course 

 is now advocated by both Stephani and Schiffner, who included 

 Plagiochasma in their proposed lists of nomina conservanda 

 presented at the International Botanical Congress of Brussels in 

 1910. The name Plagiochasma is therefore used in the present 



In 1 88 1 Leitgeb (18, p. 51) showed that P. Rousselianum 

 belonged in the genus Clevea, proposed by Lindberg in 1868, and 

 the species is now known as C. Rousseliana (Mont.) Leitg. In 

 1899 Howe (14, p. 39) showed that P. erythrospermum was a 

 synonym of Clevea hyalina (Sommerf.) Lindb. Between 1881 

 and 1898 the following species of Plagiochasma were published 

 (some of them under the name Aitonia): A. suhplana Spruce and 

 A. lanigera Spruce (32, pp. 567, 568), both of Ecuador; A. extensa 

 Steph., of Australia (33, P- 17); A. eximia Schiffn., A. Fischeriana 

 Steph., and A. microcephala Steph. (34, pp. 300, 301) all three of 

 Africa; A. fissisquama Steph. of China (35, p. 209); A. japonica 

 Steph., of Japan (36, p. 54); and P. pterospermum Massal., of 

 China (21, p. 46, pi. 13, f. 18). The various species added to the 

 genus since the Synopsis Hepaticarum increased the total number 

 to twenty-eight. 



In 1898 Stephani (37) published the last general account of 

 Plagiochasma in his Species Hepaticarum. With the exception of 

 Griffith's species, three of which he mentions but does not describe 

 on account of the lack of available material for study, he recognizes 

 as valid all the species previously published. He intimates, how- 

 ever, that P. pterospermum is probably a synonym of P. fissi- 

 squamum. Besides transferring to Plagiochasma the various 

 species described under Aitonia he restores to P. Aitonia and P. 

 Colsmannianum their original specific names and describes them 

 as P. rupestre and P. nepalense respectively. He likewise proposes 

 the following seven species as new: P. dschallanum, P. teniie, P. 



