164 Prof. Don's Descriptions of two new Genera of the 



hold an intermediate station between them. Their indefinite thecse, varying 

 from 3 to 20, and their naked buds, will distinguish them from Abietinece, 

 while their fewer ovula, deciduous pericarpia, and strobiliform female spike 

 will separate them from Cupressinece. The species of Araucaria naturally 

 separate themselves into two groups, characterized by peculiarities of habit 

 and structure, as well as by their geographical distribution. The three Poly- 

 nesian species having four cotyledons, and presenting a difference in the posi- 

 tion of the leaves in the young and adult plants, have also fewer thecse, and 

 the crests of the anthers are short and closely imbricated ; while the two 

 South American species present no difference in the position of the leaves in 

 the immature and adult plants ; the crests of the anthers are elongated and 

 squarrose, and the thecee double the ntimber. The Chilian Araucaria imhri- 

 cata extends along the Cordilleras of the Andes from the 35° to about the 

 50° of S. latitude, while the Brazilian species occurs in the provinces of Rio 

 de Janeiro and Minas Geraes between the 15° and 25° of S. latitude. The 

 Araucaria excelsa appears to be exclusively confined to Norfolk Island, and 

 the Cunninghamii to the east coast of New Holland, between the 14° and 

 30° of S. latitude ; the other species {A. Cookii, Br.) is limited to New Cale- 

 donia and some small islands adjacent ; and it is not improbable that the 

 interior of New Guinea or Borneo may afford a fourth species of the same 

 group, which, if it does not possess characters sufficiently important to rank 

 as a distinct genus, it at least constitutes a very marked section, for which 

 Salisbury's name of Eutassa may be retained. The Polynesian species are 

 remarkable for having the vessels of their fibrous tissue furnished on the sides 

 parallel to the medullary rays with two or three rows of closely approximated 

 and alternating dots having a hexagonal outline ; nor am I aware whether this 

 peculiarity extends to the South American species, and to the genera Cun- 

 ninghamia and Dammara, a point which I hope soon to be able to ascertain*. 



* Having recently had an opportunity of examining the wood of Araucaria imbricata and brasiliana, 

 and also of Dammara orientalis, I am now enabled to set this question at rest. Tlie vessels composing 

 their fibrous tissue present the same structure, having one or two rows of closely approximated dots 

 with usually an angular outline, which, however, is not so regularly hexagonal as in Araucaria excelsa 

 and Cunninghamii, from the circumstance of the dots being often in a single series, but when they hap- 

 pen to be arranged in two rows they are always alternate. The vessels of Cunninghamia sinensis have 

 the dots in single rows, with a circular outline, but they are smaller and more numerous than in Pinus. 



