266 



FLORA OF NEW ZEALAND. 



attenuated above or below, furnished at the base with a minute, hyaline, elliptic connecting-joint. Fr 

 narrow. — M, J. B. 



Tribe VI. NOSTOCHINBJ3. 



Gen. CIX. NOSTOC, Vmch. 



(Vauch. Conf. p. 203. Ag. Syst. xviii. Kiitz. Sp. Alg. p. 295.) 

 1. Nostoc vermcosum, Vauch., Conf. p. 225. i. 16./. 3. Kiitz. Sp. Alg. p. 300. 

 Hab. In fresh-water streams, Canterbury Plains, In/all. (Europe and North America.) 



[^Liehenes. 

 <dt-rings very 



Nat. Okd. CIV. LICHENES. 



By the Rev. Churchill Babington, B.B., F.L.S. 



The following enumeration of New Zealand Liehenes and Byssacece comprises about 150 species, of which 

 at least 100 are also found in Britain. The term species is here taken in the larger sense; for a much 

 greater number of forms, often easily to be recognized, undoubtedly occur in the country. Thus the first 

 species, JJsnea larbata, comprises six Acharian species, or, as I should call them, slightly differing forms. 

 This catalogue, though probably sufficiently complete to give a general notion of the distribution of genera 

 in the country, and of their relative magnitudes, to some extent does, notwithstanding, I am firmly con- 

 vinced, fall considerably below the true number of species inhabiting the islands ; in fact, there is no doubt 

 that specimens, which I am unable to name satisfactorily, and yet am unwilling to describe as new, belong 

 to species not occurring in the following pages. In no class of plants is there so great a liability to error 

 as in the Lichens : in no class of plants ought new species to be proposed with greater caution, — it may 

 almost be said, with greater reluctance. There are enough, and too many, bad species in this Order 

 already, and it is to be feared that a few may have here been added to the number. The remark of 

 a great botanist, though somewhat paradoxically expressed, has a truth underlying it : " In other tribes of 

 plants, the more we study them the more species we discover : among Lichens, the more we study them 

 the fewer we find them." 



It thus becomes clear that the lichenological flora of a country requires to be studied by a native bo- 

 tanist, who may recognize a protean species by a knowledge of its living forms, or, as Pries expresses it, of 

 its history. Without this knowledge, especially in the case of crustaceous Lichens, it is oftentimes hope- 

 less to attempt to arrive at a clear result ; and I am confident that the more difficult species of the southern 

 hemisphere, even of the higher genera (of Sticta, for example) will never be properly elucidated, till they 

 have been described and limited by some one who is familiar with them in a living state. I have strong 

 suspicions that several species which have been here kept as distinct will prove to be only remarkable varie- 

 ties of the same plant ; and, on the other hand, I may have occasionally erred in reducing two or more 

 described species to one. Even the European species of the more difficult genera are at present very ill 

 understood. 



The family of Liehenes is more cosmopolitan in its species than any other known tribe of plants ; 

 the more it is studied, the more this is found to be the case ; and one reason why the variation of the 

 species is sometimes so exceedingly great, is because many of them exist under almost every condition 

 of latitude, altitude, and climate. The fact of their general distribution teaches also another lesson, that 

 a lichenist should be slow to describe new species without some tolerable acquaintance with the Order 

 generally. This remark has repeatedly forced itself upon my mind while engaged in the present work, 



