138 COLLINS AND HERVEY. 



on the same Fucus plumosus L. ; Agardh's genus has been generally 

 accepted, and many recent species have been included in it. 

 Ruprecht, however, 1856, p. 335, calls attention to the priority of 

 Stackhouse's name, and makes the combination Pluviaria aspleni- 

 oides, and also uses the P. pectinata of Stackhouse. Otto Kunze, 

 1891, p. 911, takes the same position, and makes new combinations 

 for 16 species of Ptilota, some of which, however, are unnecessary, 

 as the species had already been properly- transferred to Eujitilota 

 Kiitz. Schmitz, 1889, p. 450, retains Ptilota for most of the 

 species, including Stackhouse's type for Plumaria, but revivies 

 Plumaria for Ptilota elegaiis, Bonnemaison, a species unknown to 

 Stackliouse; and in 1896, p. 7, transfers to Plumaria, Ptilota Schous- 

 hoei Bornet in Bornet & Thuret, 1876, p. 34, CaUithamnion elegans 

 Schousboei in Agardh, 1828, p. 162. Under the international rules of 

 nomenclature, and probably under any rule, the name Plumaria 

 must be retained for Stackhouse's type, P. plwnosa and its congeners; 

 Ptilota founded on the same species, has no standing, and the only 

 name we find available for the species placed under Plumaria by 

 Schmitz is Gymnothamnion J. G. Agardh, 1892, p. 27, type Callitham- 

 nion elegans Schousboe. Accepting this in place of Plumaria Schmitz, 

 not Stackhouse, it will include Gymnothamnion elegans (Schousboe) 

 J. G. Agardh, 1892, p. 27; CaUithamnion elegans Schousboe in Agardh, 

 1828, p. 162; Bornet & Thuret, 1876, p. 32, PI. X; Ptilota Schousboei 

 Bornet in Bornet & Thuret, 1876, p. 34; Plumaria Schousboei Schmitz, 

 1896, p. 7. G. sericeum (Harvey) comb, nov.; Ptilota sericea 

 Harvey,^^ 1846-1851, PI. CXCI; P. degans Bonnemaison 1828, p. 70; 

 Plumaria elegans Schmitz, 1889, p. 450. G. Harveyi (Hooker) 

 comb. nov. ; Ptilota Harveyi Hooker, 1845, p. 271 ; Plumaria Harveyi 

 Schmitz, 1896, p. 7. G. pellucidum (Harvey) comb, nov.; Ptilota 

 pellucida Harvey in Hooker & Harvey, 1853-1855, p. 257; Plumaria 

 pellucida Schmitz, 1896, p. 7; also a new species, described below. 



The taxonomy is somewhat complicated ; of the five species credited 

 to this genus, two were published in 1828, Ptilota elegajis and CaUi- 

 thamnion elegans; in 1876 Bornet transferred the latter to Ptilota, 

 but as the specific name elegans was preoccupied, changed it to P. 

 Schousboei. In 1896 Schmitz transferred both to Plumaria with 

 specific names unchanged, but in 1892 J. G. Agardh had used CaUi- 

 thamnion elegans as the type of his new genus Gymnothamnion, hence 



18 Fucus sericeus Gmclin, 1768, p. 149, PI. XV, fig. 3, from Kamtschatka, 

 can hardly be a Gymnothamnion. See Ruprecht, 1856, p. 337. 



