1016 



dioica, Capsella, Poa anniia, Polijgonnm auiculare, Ranunciilus repens 

 and Cerastiiim glomeratiim. 



A large palch of Cirsiiim arvense growing to a heighl of 1^/2 me- 

 tres was seen along with Riimex crispiis, Tanacetum vulgare, Agro- 

 pyrum repens, Brassica campestris and Senecio vulgaris. 



On a path in the Bo, aniong other piants there was Plantago 

 major, which was observed in this station by E. Rostrup as early 

 as 1867 ; since then it has persisted here without being distributed any 

 further. Anchusa arvensis presents a similar case; it was also found 

 in 1867 as a weed in a potato field at Sand on Sando, and we saw 

 it there still 30 years after. These species have ripened their fruits 

 year after year. Certain other weeds have not fared so well, and 

 have consequently disappeared from the Færoese flora. Thus Lyng- 

 bye in 1817 found Agrostemma githago as a weed in fields at 

 Skjælling on Stromo, and Lolhim perenne at Ejde on Ostero (see 

 Ostenfeld 1907, p. 860), but neither of them has since been ob- 

 served at those piaces. 



Rostrup in 1867 collected Brassica nigra, Geranium molle, 

 Veronica hederifolia, Agrostis spica vend and Raphanus raphanistrum 

 at Thorshavn, but we could not fmd even a single specimen of 

 them. Several other examples of a similar kind might be added. 



In this formation phanerogams alone have been noticed, because 

 mosses and lichens do not favour a substratum so recently formed 

 and so liable to change as the soil of fields and gardens. 



Some few mosses, however, have their habitat here and deserve 

 recognition, tor example Funaria hygrometrica and Brynm argent- 

 eum, but they are not particularly abundant. 



c. The metamorphic formation. 



The transformation of a cornfield into a Bo or meadow takes 

 two or three years, during which period there is a characteristic 

 vegetation, consisting of a mixture of a large number of weeds with 

 some of the species of the meadow. During the year of the corn 

 crop the weeds occupy the ground so that during the next year 

 they are entirely dominant. After this they are superseded gradu- 

 ally by the species of the meadow, which come in more slowly, 

 but none the less surely. This mixture of piants which occupies 

 the field in these years of struggle, I have named the »metamor- 

 phic formation«. 



