294 THORODDSEX 



The snow-coverings in the lowlands generally melt away in April 

 and the period of growth begins in May. But the time for the ap- 

 pearance of the plants differs considerably throughout the extent of 

 the island, not only according to position and height above sea- 

 level, but also on account of the conditions of weather in different 

 years. 



In south-west Iceland, in the neighbourhood of Reykjavik, in 

 somewhat favourable years a few species flower at the end of April, 

 e. g. Saxifraga oppositifolia and Arabis petrcea, but in the beginning 

 of May a great many plants are in bloom, e. g. Salix herbacea, Al- 

 chimilla alpina, A. viilgaris, Draba incana and Silene acaulis, some- 

 what later and until the middle of the month Caltha palustris, Car- 

 damine pratensis, Armeria maritima, Rnmex acetosa, Oxyria digyna 

 and at the end of the month Ranunculus acer, Taraxacum uulgare, 

 Cerastium alpinum, C. vulgare, Thalictrum alpinum, Arctostaphylus 

 uva ursi, Pinguicula viilgaris, Betula nana and others. The common 

 flowering period begins in June; and June and July are the months 

 richest in flowers. For the rest, the flowering period is highly de- 

 pendent on the weather; it may be delayed in colder years, espe- 

 cially in ice-years, but on the other hand, during prolonged periods 

 of thaw in winter some flowers may open in February and March. 

 On the northernmost points of land and on the plateau the time for 

 flowering is naturally somewhat later. 1 



The number of plant-species found in Iceland cannot yet be 

 stated with any certainty, but later in this work the lists and col- 

 lections will be critically investigated and new species added to the 

 list. 2 The number of species of known phanerogams and vascular 



1 For observations regarding the time of flowering in East Iceland in 1893 

 and 1894 see Helgi Jonsson: Vinter- og Vaar-Ekskursioner i 0st-Island (Botanisk 

 Tidsskrift, 1895, pp. 274275 and 292294), and in the neighbourhood of Reykja- 

 vik in 1873 1875 see Th. Thoroddsen's notes in Gronlund s Karakteristik af 

 Planteva?xten paa Island, pp. 17 18. Moreover, there are some notes on the sub- 

 ject which have not as yet been published; but they make no difference as regards 

 the general sketch of the spring-flowering given here. 



The chief floristic works on Iceland are the following: - - St. Stefansson: 

 Flora Islands, Kobenhavn, 1901. W. Lander Lindsay: Flora of Iceland. (New 

 Philosophical Journal, New Series, Edinburgh. July, 1861 ; 40 pages). C. C. Babington : 

 A Revision of the Flora of Iceland. (The Journal of the Linnean Society, Vol. XI, 

 London, 1871, pp. 282 348). Chr. Gronlund: Bidrag til Oplysning om Islands 

 Flora. Hojere Kryptogamer og Fanerogamer. (Botanisk Tidsskrift, 2. Rsekke, IV, 

 1874, pp. 36 85). Chr. Gronlund: Islands Flora. Kobenhavn, 1881. Chr. Gron- 

 lund: Afsluttende Bidrag til Oplysning om Islands Flora. (Bot. Tldsskr., XIV, 1885, 

 pp. 159217). H. F. G. Stromfelt: Islands karlvaxter. (Ofversikt af Kgl. Vetensk. 



