io 4 ANNALS OF SCOTTISH NATURAL HISTORY 



cannot be identified with any hitherto known to me. The 

 first described has peculiarities such as to warrant its being 

 included in a new subgenus. 



In the following measurements of cells, etc., the micro- 

 millimetre, or the millionth part of a metre, is taken as the 

 unit. This unit is now generally indicated by the Greek 

 letter /n. This letter will, however, not be appended in any 

 case, so that 8, for instance, means 8 micro-millimetres. 



A review of species of Cainpylopus sent to me from 

 various parts of the world has enabled me to associate the 

 moss in question with one from New Zealand, placed by 

 Mr. Mitten in the genus Trickostomum, under the name 

 Tr. leptodum. This is Cainpylopus leptodus of Montagne. 

 The habit of the moss is entirely that of a Campylopus, but 

 Mr. Mitten, finding the teeth of the peristome slender and 

 split nearly to base, decided, on this peculiarity alone, to 

 classify it with the Tricliostoma. I prefer to refer it to a 

 subgenus which Mitten has named Pilopogon. There is, 

 however considerable dubiety as to whether the specimens 

 in my possession from New Zealand are identical with the 

 moss described by Mitten in Hooker's " Flora of New 

 Zealand," inasmuch as my specimens have the broad nerve 

 of Campylopus, whereas the nerve is there spoken of as 

 "slender." As I have not hitherto been able to obtain 

 authentic specimens of Mitten's moss, it might be as well, in 

 the absence of fruit in the Scottish specimens, to constitute a 

 new subgenus under the name Trachypogon. 



The following is the diagnosis of the Scottish species : 



CAMPYLOPUS (TRACHYPOGON) AURESCENS. Tufts densely csespi- 

 tose, yellow or golden yellow above, pale brown beneath ; stems i 

 to 2 inches in height, stoutish, sparingly dichotomous, often 

 fastigiately branched above, sparingly radiculose below, fasciculate- 

 leaved ; leaves lanceolate or lanceolate-subulate above, tipped with 

 a longish denticulate hyaline hair, margin incurved throughout ; 

 nerve \ to \ the width of leaf a little up from base a cross-section 

 shows it thickened in middle and often bulging behind, with two 

 rows of opaque cells, the anterior row showing cells 5 to 9 in 

 diameter, the posterior 4 to 6 diameter. In the middle of nerve in 

 front are occasionally seen traces of very minute cells, 3 to 4 in 

 diameter, and 3 to 6 in number, as in Dicranum or Campylopus 

 alpinus, but these cells are often entirely suppressed. The cells of 



