356 THE JOURNAL OF BOTANY 



name," and that to make it effective he should have added 

 " Bryitm ruhelluvi Hoffm., etc." But the citation of " (Hoffm.) " 

 together with the specification of its inclusion in the Subgenus 

 or Section Erijthrophyllum makes it absolutely certain what 

 species he is referring to, and it would seem somewhat gratuitous 

 hair-splitting to reject the combination on this ground. If 

 retained in Barhula the name should I think therefore stand as : 

 Barbula rubella (Hoffm.) Lindb. Muse. Scand. p. 22 (1879). 



DiCEANOLOMA DiCHOTOMUM (P. Beauv.) Par. 



C. Miiller, Syn. i, describes Dicranum dichotomuvi (P. Beauv.) 

 Brid. from I. Bourbon, in the section with the nerve serrate (at 

 back) ; D. Billardieri Schwaeg., from Australia, Cape of Good 

 Hope, etc., in that with nerve smooth. The distinction cannot 

 hold, as the Australasian plant has the nerve normally serrate at 

 back. He does not compare the two species otherwise, nor do 

 the descriptions suggest any difference, beyond the fact that the 

 inner perichgetial leaves of I). Billardieri are described as "intima 

 sensim longius acuminata obsolete denticulata " ; but this again 

 is erroneous, as one of the most essential characters of the 

 Australasian species consists in the fact that the inner perichgetial 

 leaves are obtuse and muticous (rarely if ever with a short mucro), 

 a character scarcely if at all found in any other species of the 

 genus. 



Hampe subsequently separated the Cape plant as D. com- 

 mutatum, and subsequent authors have assumed its distinctness 

 from D. Billardieri and D. dicJiotomiwi. 



If the Australasian plant were a locally distributed species, 

 and if the separating characters of the African plants were con- 

 stant, even though slight, it would be natural to consider them 

 as distinct species. The case, however, is far otherwise. To 

 begin with, D. Billardieri is a wddely spread and common species 

 through a considerable part of the sub-antarctic region. The 

 Handbook of the N.Z. Flora gives it as " abundant in all the 

 islands, and as far south as Campbell's Island." I have from 

 twenty-five to thirty gatherings of it in my herbarium from these 

 regions. It is a common plant in Australia and Tasmania. It is 

 also recorded by Mitten from Juan Fernandez, Peru and Valdivia, 

 and by Cardot from numerous localities in Chile, Patagonia, 

 Fuegia and the Falklands. I have studied the New Zealand and 

 Australian plant carefully ; like other widely distributed and 

 common species, it shows a fair range of variation in habit, size, 

 length of leaf, and certain structural characters, but it is by no 

 means a highly variable moss, and it has a habit and especially a 

 leaf-structure which are very characteristic and by which it is 

 easily recognised. I think therefore it is not assuming too much 

 to state that in my opinion all the African plants mentioned, 

 together with one or two to be referred to later, are absolutely 

 identical with the Australasian and South American species. 



I have examined the type of Hampe's D. commutatimi, to- 

 gether with his MS. notes. He gives certain points of habit. 



