to the Antarctic Regions. 35 



except near the ground, while the Tree Ferns of Hobart Town are 

 thickly covered with similar fibres from the very summit. The origin 

 of these fibres and the circumstances under which they are produced, 

 are unknown, and should, if possible, be determined ; indeed, the 

 manner of growth of these plants in all other particulars is an in- 

 teresting subject for careful investigation, as are also the circum- 

 stances under which this tropical form of vegetation is produced 

 upon Mount Wellington. In the event of the expedition visiting 

 the southern part of New Zealand, it should also be ascertained 

 under what conditions the Tree Ferns that exist there extend so far 

 beyond the usual geographical limits of such trees, and also whether 

 they are not accompanied by other forms of an equally tropical 

 character. 



The northern coast of Van Diemen's Land being in many re- 

 spects clothed with a different vegetation from the south side, it is 

 desirable to notice the peculiarities of each. At Emu Bay, there 

 exists the Gunnia australis, an orchidaceous epiphyte, which is far 

 to the southward of the general range of plants of that kind. It 

 will probably be found that this apparent exception to general rules 

 is dependent upon some local peculiarity of climate. Possibly other 

 species with similar habits occur on the same line of coast ; they 

 should be sought for, and particular attention should be paid to the 

 plants with which the orchidaceous epiphytes are associated. 



A principal object of inquiry should be, plants yielding useful 

 products of all kinds. It is in this way only that the resources of 

 foreign countries can be ascertained, and it is presumed that in an 

 expedition which will be stationary for considerable periods of time, 

 such inquiries can be easily made. Under the head of useful 

 products the following may be particularly mentioned : 



1. Dietetical, medicinal, and poisonous agents of all kinds. The 

 nature and action of the poisons employed by the natives of many 

 countries are but slightly known. 



2. Dye stuffs. Attention should be paid, especially to obtain 

 Lichens, as substitutes for the Roccella tinctoria, now becoming scarce, 

 and consequently very valuable in European commerce. The fitness 

 of these plants for this purpose may be approximately ascertained 

 by Hellot's lichen test, which is as follows : digest the lichen at 

 a temperature of 130° F. for a few hours, in a weak solution of am- 

 monia, but sufficiently strong to be tolerably pungent. One that is 

 fit for the dyer will yield a rich violet red liquid. 



3. Astringent substances adapted for tanning. It is desirable to 

 ascertain with accuracy the source of the various astringent extracts 



D 2 



