1 1 6 The Scottish Naturalist. 



those of ohtusifolius. R. aquaticus Auct. Suec. is not yet known 

 as British, but from its distribution there is no reason why j 

 should not occur. It is probably owing to the fact that this name 

 has been, and still is, applied so variously, that Nyman credits 

 England and Scotland with B. Hippolapathum Fries instead of 

 with B. domesticus Hartm. Altogether, the Shetland Docks ap- 

 peared to me very interesting ; and I regretted that I had not the 

 means to make a more extensive collection of the various forms, 



Populus. I did not see P, nigra at the Burn of Sunday- 

 banks ; but it was nearly dusk when I reached the spot. It is 

 an extremely unlikely tree to have been planted here ; and I have 

 no doubt the tree found here will prove to be P. tremula, 

 jvhich occurs as a native of Orkney and Caithness. 

 : Salix herbacea L. Common on the hills of Foula, at 

 i ooo- 1 400 feet. 



Sparganium affine Schniz. This is, apparently, the com- 

 mon species of the islands. According to Dr. Neuman, who has 

 for some time studied the Scandinavian species, there are three 

 forms included under this name. All of these occur in Britain, 

 but I am at present imperfectly acquainted with their distinguish- 

 ing features. So far as can be seen from the specimens, none of 

 which are in good fruit, the common form in Shetland is S. 

 affine, genuinum ; and it occurs copiously (U.) in the Loch 

 of Cliff, Burn of Burrafirth, &c. Besides this, another form 

 occurs, which Dr. Neuman regards as a distinct species or sub- 

 species. Fortunately, I obtained a few examples of this plant ' 

 in good fruit. I await the publication of my friend's expected 

 paper on the genus, before giving a description of this plant. 



+ S. minimum Fries. ? A plant is abundant in the Mai- 

 land Burn, Unst, which Dr. Neuman believes to be this species. 

 Owing to the depth of water all the flower-heads were submerged ; 

 and consequently the female heads were not fertilised, so that the 

 fruit was very imperfect. The only other European species to 

 which the plant could be referred is S. hyperboreum Lsest. ; but 

 Dr. .Neuman reports as indicated above, after examining the fruit 

 in the fresh state.* J 



Potamogeton heterophyllus Schreb, and P. nitens. Web. : 



* (I should be grateful for examples of Scotch Spargania in ripe fruit, either 

 on |oan or in exchange. ) 



