l6 Mr. BROWjsr, on the Proteacea of Jussiett. 



who, however, have frequently neglected it in practice: nor do 

 1 find any one who has steadily kept it in view, except Aubert 

 Du Petit-Thouars in his excellent work on the plants of Mada- 

 gascar and the Isles of France and Bourbon. 



The bursting of the antherae has, it is true, been generally 

 observed, and many of its most unusual modes have been in- 

 troduced into the characters of genera ; but the examination of 

 these organs, at a still earlier period, has been universally neg- 

 lected; and hence the very imperfect knowledge which, even 

 now, is possessed of their real nature in two of the most re- 

 markable families of plants, .the Orchideae and Asclepiadeae. 



Examples of the great advantage of observing the antherae in 

 this early stage will hereafter be given in my general remarks on 

 the order which is the proper subject of this essay. But I trust 

 I shall be pardoned for here introducing some account of their 

 structure in Asclepiadeae, as it will enable me not only to bring 

 forward the most striking proof of the importance of this consi- 

 deration with which I am acquainted, but also, as I apprehend, 

 to decide a question which has long occupied, and continues to 

 .divide, the most celebrated botanists. 



The point in dispute is whether this order, comprehending 

 Asclepias, Cynanchum, Pergularia, Stapelia, and several genera, 

 at present confounded Avith these, ought to be referred to Pentan- 

 dria or Gynandria, and, if to the latter, whether the antheras are 

 to be considered as five or ten; all of which opinions have had 

 advocates of the greatest name in the science. 



According to Linnaeus, Jussieu and Richard they belong to 

 Pentandria. 



Linnaeus has assigned no reason for his opinion, Avhich, how- 

 ever, it appears he retained after he became acquainted with the 

 observations of Jacquin and Rottboell ; but it is probable he 



was 



