1836.] Observations on the Flora of Courtallum. 8$ 



a difference worthy the most attentive investigation. In the 

 former the dry est season of the year is the most healthy, 

 and that during which their recesses may be most safely ex- 

 plored ; while in the latter it is during the height of the 

 rains ; and that too, although the vegetation is much the 

 same in both. But, in both, so far as yet known, the vege- 

 tation no where, except on the Neilgherries, presents an indi- 

 cation, of any part of the hills, attaining an elevation suffi- 

 cient to place them beyond the influence of the fever zone. 

 Some may, and no doubt do, attain an elevation exceeding the 

 nearly ascertained limits of that zone on the Neilgherries, 

 such for example as the Shevaroys, but they have not mass 

 enough at that elevation, to relieve them entirely from its 

 pestilential influence. 



In justice to my subject I have thought it necessary to in- 

 troduce these additional preliminary observations, to show 

 more clearly the object and bearings of such investigations ; 

 and, I trust I may add, not without the hope of inducing 

 some of those who have hitherto paid but little attention to 

 such enquiries, to devote some portion of their leisure to such 

 pursuits. 



The method or arrangement, which I propose following in 

 these papers, is that of Professor Decandolle. He in place of 

 commencing his sy sterna vegetabilium with the more simple, 

 and rising to the more complex forms, has adopted the oppo- 

 site course, of commencing with the more complex forms, 

 and descending to the more simple ; from their structure and 

 organization being more obvious, yet, though more complex, 

 easier understood. 



As every linear arrangement of the series of natural orders 

 must be more or less artificial, this truly great botanist has 

 adopted one, which affords many facilities for discovering the 

 place of any unknown plant, by grooping all the Dicotyledo- 

 nous orders under four great classes, distinguished, generally, 

 by very obvious characters. In the first f Thalamiflorce J the 

 petals are distinct and inserted along with the stamens, when 

 present, below the ovary or young seed vessel ( hypogynous J, 

 without any reference to the number either of stamens or 

 pistils, or whether only one or both are present— their posi- 



