»7 

 lu 



D 



193 



Charge Australes et A3Ptarctic.e, or characters and observations 

 on the Charace.e of Australia and the Southern circumpolar réglons ; 



by Dr. Alexander Braun. 



m 



Aquatic plants hâve been iu gênerai regarded as cosmopolites, wliich, 

 unrestrained by the coinmon limita of phytogeographical régions, are to 

 be found with unchanged spécifie types in the inost distant parts of the 

 world. The following enumeration, however, by no means confirais 

 this assmnption, being confined to a séries of quite peculiar species 

 representing the family of Characeœ in Australia. 



Robert Broicn, in his Prodromus Plorœ Novœ Hollandiœ, enumerates 

 only two species of the family of Characeœ. I owe the knowledge of 

 thèse, and a third not yet described New Holland species, to the kind 

 communications of the celebrated author. In the year 1843, I pub- 

 lished in the 17th volume of Linnœa, the Characeous plants collected 

 by M. Preiss, m New Holland, by which the number of species known 

 to this country amounted to eight. The most considérable increase, 

 however, to our knowledge of the Australian Characeœ is due to the 

 liberality with which Sir W. J. Hooher has opened to me his rich collec- 

 tions. Among other precious materials, I find there a most important 

 séries of Characeœ, collected on the Swan Eiver by the indefatigable 

 Mr. James Drummond ; as well as several Antarctic species collected by 

 Dr. J. D. Hooher during the voyage of the Discovery Ships Erebus and 

 Terror, which are reinarkably interesting from their analogy with those 

 of the northern polar région. With thèse the number of the Australian 

 species amounts to sixteen, or with the Antarctic ones, to eighteen. As 

 I hâve remarked, ail thèse species are peculiar to thèse countries, and to 

 be found in no other part of the world. Only two of them hâve a near 

 resemblance with species otherwise known, so that, by a less restricted 

 définition of species, they might be regarded as varieties ; — namely, 

 Nitella penicillata, from Van Diemen's Land, which resembles much 

 N. gracilis from Europe, and N. Antarctica, from Kerguelen's Land, 

 which has great analogy with the northern N. nidifica. The most 

 singular and curious species, both of the true genus Chara and of 

 Nitella, are those from the Swan Eiver. Although there hâve been 

 found not less than ten species at that seulement, uone of them shows 

 the calcareous incrustation, characteristic of many of our European 

 species, but ail are smooth and pellucid, without any incrustation or 

 vol. i. 2 c 



t Ho o A^a^j v ^wwv ilP h 



I .!:■■"■■ ?• lC \- 



