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THE BRITISH SPECIES OF ARCTIUM. 

 By A. H. Evans, M.A. 



Of late years there has been a widespread idea in Britain that 

 the genus Arctium presented great difficulties to its students, both 

 as regard nomenclature and the identification of our native species. 

 The synonymy certainly involves some difficult questions, but I 

 hope here to show that the identification is comparatively simple. 

 A great part of the confusion is probably due to excessive reliance 

 on herbarium specimens, the use of which, though most important 

 in their proper place, should in the case of Arctium follow, and 

 not precede, the examination of freshly gathered material. Most 

 of the forms lose something of their characteristic appearance 

 when pressed, and, if the examples to hand are not mature and care- 

 fully selected, they may easily lead to erroneous conclusions. The 

 difficulties are of course greatest to those persons residing in 

 districts where only one or two of the forms are found, when they 

 attempt to follow the arrangement in a single text-book. In 

 Cambridgeshire, however, we are particularly fortunate, as all the 

 members of the genus recorded for Britain are comparatively 

 abundant, and in at least one locality may all be found growing 

 within a few hundred yards of one another. 



I have been interested in this small group of plants for many 

 years, and for the last two or three have made a careful study of 

 it, receiving much assistance at the British Museum, from the 

 Editor of this Journal, and others, as well as from various friends 

 and correspondents. Last year I spent most of the summer 

 vacation in revisiting various counties in search of species of 

 Arctium, going by way of Surrey, Hants, and Devon to Cornwall, 

 and thence northwards to Northumberland and the Eastern Border 

 counties, with a short sojourn in Stirlingshire. I also procured 

 specimens from many places which I was unable to reach in the 

 time at my disposal, while I had previously visited Orkney and 

 Shetland. 



No one who has examined a large number of these plants in 

 the field is likely to assign his specimens to more than four species, 

 and this is in accordance with Professor Babington's conclusions 

 in 1856 (Ann. Mag. N. H. xvii. 369), if we allow for the fact that, 

 of the five there given, he afterwards admitted that A. tomentosum 

 was unknown in Britain. But I submit that there are only three 

 species as yet known in the country, and that the fourth form is 

 a subvariety, which I have renamed to prevent confusion, as will 

 be seen in the synonymy given below. This is "A. nemorosum 

 auct. angl," which Babington, in the fourth edition of his Manual 

 of British Botany, and in the article cited above, identified with 

 A. intermedium Lange. He then called the real A. intermedium 

 A. pubens, though he subsequently withdrew this name and 

 changed it on every sheet in his herbarium. 



Our largest species, A. Lappa, can hardly be confounded with 

 any other by those who have once seen it in flower and mature 

 Journal of Botany. — Vol. 51. [April, 1913.] k 



