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VIII. Descriptions of two new Genera of the Natural Family of Plants called 

 Coniferse. By David Don, Esq., Libr. L.S., Prof. Bot. King's College. 



Read April 17th, 1838. 



X HE Coniferce undoubtedly constitute one of the most interesting^ families 

 in the vegetable kingdom, whether considered in connexion with the former 

 vegetation of the earth, or in reference to their peculiarities of structure, or as 

 objects of utility, affording to man an abundant supply of valuable materials 

 employed extensively in tffe arts and domestic oeconomy. Their habit and struc- 

 ture are so peculiar that they have been ranked as a separate family by the 

 earliest writers on Systematic Botany. Richard in his valuable work, " Me- 

 moires sur les Conif^res et les Cycadees," has distributed the family into three 

 groups, denominated by him, from the typical genera of each, Abietihece, Cu- 

 pressinece, and Taxinece ; the first may be characterized by their female spikes 

 forming a cone or strobilus, their ovula being in pairs, and by their scaly buds ; 

 the second by their reproductive organs having a tendency to become inde- 

 finite, by their naked buds, and other peculiarities of habit ; the third by their 

 female spike being usually reduced to a single flower, with a solitary, com- 

 pletely naked ovulum, whose external integument assumes a fleshy consist- 

 ence and resembles an arillus. All three will be found to correspond remark- 

 ably in the structure of their male flowers ; and the differences presented by 

 their female inflorescence are more apparent than real, for they consist rather 

 in the degree of reduction of parts than in actual structure. Their organs of 

 nutrition present a remarkable degree of uniformity in their structure, and, 

 indeed, it would be difficult to point out a family so completely natural, and 

 one whose groups pass so insensibly into each other. 



To the three groups above mentioned I propose to add a fourth, which may be 

 named Araucarinece, and to consist of Araucaria, Dammara, and perhaps Ciin- 

 ninghamia, which correspond with Cupressinece in the tendency of their repro- 

 ductive organs to become indefinite, in their naked buds, and in their general 

 habit. This group being mutually related to Abietinece and Cupressinece, would 



