102 Clironicles of Science. [Jan., 



ing at great elevations; the latter by two, the leaves of one of 

 which are used by the natives in the place of tea ; a very remarkable 

 undescribed Ficus forms a considerable portion of the larger vege- 

 tation, growing sometimes 100 yards across, with very nnmerons 

 root-stems. The castor-oil plant and Solanum laciniatum are 

 among the most troublesome introduced weeds. Ferns are very 

 abundant, but of non- Australian types; the genera Adiantum and 

 Aspidium. so abundant in Australia, New Zealand, and Norfolk 

 Island, were not observed. 



The Lichens of Greenland. — Dr. Lauder Lindsay has worked 

 out with great care, in an article read before the Botanical Society 

 of Edinburgh, an account of all that is at present known respecting 

 the Lichens of Greenland. While in 1840 only 59 species had 

 been recorded, Dr. Lindsay is now able to enumerate 263 as 

 natives of Greenland, and thinks that this number may probably be 

 raised to 300. The degrees of latitude within which they have been 

 collected range from 60° to 75°, the majority having come from 

 about 70 : , a few from as far north as 82°. The almost entire absence 

 of arboreal vegetation in Greenland necessarily affects the character 

 of the Lichen- flora, very few corticole and foliaceous species being 

 found, but a great preponderance of the saxicole forms. One pro- 

 minent feature is the great abundance of the sombre-coloured 

 Umbilicariw, giving in many parts a funereal colouring to the 

 landscape. Deducting the species that are mainly or entirely con- 

 fined in their distribution either to Greenland or to Arctic countries, 

 the majority at least of the remainder occur on the Scandinavian 

 Alps, and many of them on the Alps of Scotland and Switzerland, 

 or generally on those of continental Europe ; while a considerable 

 number are common British forms. The lichen-flora of Greenland 

 differs, on the other hand, very considerably from that of Arctic 

 America. The lichens of Spitzbergen and its islets are as numerous 

 as those of Greenland, notwithstanding the smaller area ; while the 

 whole list of Melville Island lichens contains only twelve species. 

 There is no record of any species of lichen being turned by the 

 Greenlanders to any economic purpose, notwithstanding the abun- 

 dance of Cladonia rangiferina, or the M Beindeer-moss," and of 

 other species which, in other Arctic countries, have been serviceable 

 in supplying the wants of man or animals. 



Hibernation of Duck-weed. — It has long been known that some 

 species of Lemna, or duck-weed, produce, at the approach of winter, 

 leaves of a different character to those formed in the spring, which 

 fall to the bottom of the pond or stream, enabling the plant to live 

 through the winter. A series of more accurate observations on this 

 point is recorded by II. Tan Horen in the ' Bulletin de la Societe 

 Boyale de Botanique de Belgique.' The species of Lemna indige- 

 nous to Belgium are the same as those found in this country : of these 



