1015 



hardly ever sets seed, all Ihese species are annuals. This is also 

 the case with a number of other species which are frequently do- 

 minant weeds in the arable fields, but which also occur in other 

 formations (e. g. Stellaria media, Montia, Cardamine hirsiita). 



Some notes may serve as illustrations: 



1. Barley-field at Frodebo, Sydero. Galeopsis letrahit in 

 abundance, and Brassica campestris sparse. 



2. Field of Tartarian oats at Kirkebo, Stromo. Coniinon 

 weeds: Avena sativa, Montia lamprosperma, Stellaria media and Poa tri- 

 vialis. Rather more scattered: Polygonum aviculare, Atriplex sp., Sina- 

 pis alba, Galeopsis tetrahit and Brassica campestris. 



3. Oat-field at Kirkebo, Stromo. Galeopsis, Raniinciilus repens 

 and Stellaria media in great abundance; also noted as less common: 

 Hordeum distichum, Rumex acetosa, R. domesticus, R. obtusifolius and 

 Polygonum aviculare. 



4. Barley-field at Thorshavn. Stellaria media most frequent; 

 common are: Ranunculus repens, Spergula arvensis, Poa trivialis; scat- 

 tered: Holcus lanatus, Cerastium vulgare, Senecio vulgaris and Alectoro- 

 lophus minor. 



5. Oat-field at Thorshavn. Galeopsis tetrahit was most fre- 

 quent; also noted: Brassica campestris, Cardamine hirsuta, Rumex ace- 

 tosa, Holcus lanatus, Agrostis vulgaris, leaf-rosettes of Anthoxanthum, 

 Mj'osotis versicolor, Stellaria media, Ranunculus acer, R. repens (in 

 patches) and Cerastium vulgare. 



The weed-vegetation of the gardens and around the 

 houses, the so-called Ruderal vegetation, is closely related 

 to the weed-vegetation of the cultivated fields. Both these associa- 

 tions have in common a great number of annual species, all de- 

 pendent on human activity. 



They do not attain perfect vigour except when growing on re- 

 cently tilled, loose soil (»new land«), and are unable to maintain 

 themselves for any length of time against the encroachments of 

 other piants unless assisted by man's regular cultivation of the soil. 

 The foUowing piants belong to this group in addition to the species 

 already mentioned (p. 1014): Capsella bursa pastoris, Cerastium glo- 

 meratum, Poa annua and (to some extent) Juncus bufonius and 

 Polygonum aviculare — these being annuals; also the perennials, 

 Rumex crispus, R. obtusifolius, R. domesticus and Agropyrum repens. 



Tanacetum vulgare, Aegopodium podagraria and Urtica dioica 

 might also be included, but with some limitations. 



Some examples of the weed-vegetation may be quoted from 

 my notes from Kirkebo on Stromo. Around the houses the fol- 

 lowing were common : Rumex domesticus, R. obtusifolius, Urtica 



