?50 Transactions of tlie [Ses 



Fragilaria capucina. ' Diatoma elongatuni. 



Eunotia arcus. | m n var. j3. 



Synedra splendens. i n vulgare. 



ti ulna. ' Nitzscliia linearis. 

 Tabellaria flocculosa. u sigmoideae. 



Licmophora flabellata (mai-ine). _^ 



Grammatophora mariiia (marine). "■ ^'kyptoraphidieje. 



Denticula ocellata. Isthmia nervosa (marine). 



M tenuis. Cyclotella operculata. 



X.—NOTE ON THE GENUS LAMIUM. 

 By Mr MARK KING. 



{Bead Feb. 26, 1885.) 



The Natural Order of tlie Labiatas, in which the genus Lamium is 

 found, is one of the best marked and most easily recognised of all 

 the botanical groups. The Labiates are confined to the temperate 

 regions of the earth, their number diminishing towards the tropics 

 and either pole. Tlie Lamiums, or Dead-nettles, are perhaps the 

 best-known plants of the Order, — indeed they are so familiar to all, 

 that they are frequently passed by with, it may be, a single glance ; 

 and yet, like many of tlieir humble neighbours, they possess a most 

 interesting structure, and well repay any labour which may be 

 spent in their study, as is evidenced by the remarks upon the 

 flommon Dead-nettle in Sir John Lubbock's most readable book on 

 the ' Fertilisation of Wild Flowers.' Although mainly following 

 Hooker, in his last edition of the ' Student's Flora of the British 

 Islands' — (the latest and best arrangement of our native plants) — 

 I may state that I have given some attention to the genus Lamium, 

 and would desire to add my own remarks from observation of the 

 living plant from time to time. Perhaps the most striking family 

 resemblance in tlie Lamiums is found in the whorled inflorescence, 

 with the leafy bracts, these latter being often three oi^ four times 

 as large as the leaves. The generic name is probably derived from 

 the Greek word for a throat, in allusion to another well-marked 

 characteristic — namely, the throat-like corolla. There are at 

 least jive species of Lamium indigenous to, or thoroughly estab- 

 lished in, this country, and of these four may be considered as 

 generally distributed over Britain. The genus is conveniently 

 divided into annual and jyerennial plants, — the annual forms being 

 Lamium purpureum, L. intermedium, and L. amplexicaule ; while 



