Flóra: tímarit um íslenzka grasafræði - 01.04.1966, Qupperneq 11

SUMMARY.
Dryopteris assimilis S. Walker in Iceland.
Recent Icelandic floras and also Flora Europaea report the species Dryopteris
dilatata as occurring in western and northern Iceland. Detailed morphological and
cytological studis on Icelandic material have shown, however, that the only fern o£
the D. dilatata complex occurring in Iceland is the recently described species D.
assimilis S. Walker. It is a diploid plant with 2n = 82 chromosomes, as previously
demonstrated by Walker and others from Europe and Wagner and others froni
America. That number lias been confirmed by the present writers on Icelandic
material from southwestern and northern parts of the country. D. assimilis is appar-
ently a circumpolar species, though it still has not been separated from D. dilatata
in many parts of its area, notably in North America north of the Great Lakes and
west to Alaska, and in Siberia.
ACKNOWLEDGEMENTS.
The authors want to acknowledge valuble assistance given by Mr. Helgi Hall-
grímsson, Akureyri, who sent us living and pressed specimens for this study, and
also help by Dr. Warren H. Wagner, ann Arbor, and Dr. S. Walker, Liverpool, who
assisted in the determination of the material. We are also grateful for financial
help, which in the first phase of this study came from NATO Science Grant No.
69, and in its final phases from National Science Foundation travel grant GB 3491
and researcli grant GB 3371.
Department of Biology,
University of Colorado,
Boulder, Colorado 80302, USA.
HEIMILDARRIT.
Grönlund, C. (1881): Islands Flora. Kjöbenhavn.
Gröntved, J. (1912): The Pteridophyta and Spermatophyta of Iceland. Botany of Iceland
IV. 1 : 1-427.
Heywood, V. H. (1961): Dryopteris. Flora Europaea. I : 20—22.
Löve, Á. (1915): íslenzkar jurtir. Kaupmannahöfn.
Moore, T. (1856): Nature printed ferns of Great Britain and Ireland. London.
Ostenfeld, C. H. & Gröntved, J. (1951): The Flora of Iceland and the Faeroes. Copenhagen
&: London.
Stefánsson, S. (1901): Flóra íslands. Kaupmannahöfn.
Stefánsson, S. (1921): Flóra íslands. 2. útgdfa. Kaupmannahöfn.
Stefánsson, S. (1918): Flóra íslands. 3. útgáfa. Steindór Steindórsson bjó til prentunar. Ak-
ureyri.
Watker, S. (1961): Cytogenetic studies in the Dryopteris spinulosa complex. II. American
Journ. Bot. 48 : 607—614.
Wallier, S. t Jermy, A. C. (1961): Dryopteris assimilis S. Walker in Britain. Brit. Fern
Gasette 9 : 137-140.
TÍMARIT UM ÍSLENZKA GRASAFRÆÐI - FlÓrd 9