ILLUSTRATIONS OF INDIAN BOTANY. 75 



Geogeapiiical Distribution. The true Ciiiehoiiacecc constitute a peculiarly tropical 

 assemblage of plants, being almost exclusively confined to tlie tropics or llie warmer regions on 

 either side. Within these limits the species so abound, that it is estimated they amount to about 

 l-30th of the flowering plants, a calculation which I think will be found very near the truth, and 

 which, as applied to the Indian Peninsula, will raise the estimated flora to about 5000 species, 

 as there are 154 named in our Prodromiis, and my present collection exceeds that number by 

 more than 15 species, which would be required to make good the calculation. In Europe no 

 true Cinchonaceous plant is indigenous, their place being occupied by the Stellafa;^ of which the 

 European flora includes about 100 species. 



In the tropics and warmer regions on either side, they are met with in all countries, but are, 

 as compared with Asia and America, rare in Africa. In India, species extend as far north as the 

 SOth or 31st degree of latitude, and there, wc are informed by Dr. Royle, a few of the herbascous 

 forms are met with during the moisture of the rainy season at an elevation of 6000 or 7000 feet, 

 an elevation which, as regards temperature, must furnish a climate cooler than the south of 

 Europe in the 36*^ of latitude, a circumstance showing, that, however much temperature may and 

 does affect "the distribution of plants on' the surface of tlie globe, climate also has much to 

 do with it. The following extract from my Neilgherry Plants, recently published, may not be 

 uninteresting to some of the readers of this work. 



"The predilections of this family as ^regards temperature, are decidedly tropical, or sub- 

 tropical, not a single species, excluding Stellatos^ being, so far as I am aware, indigenous even in 

 the South of Europe, while within the tropics they are estimated to constitute 1-SOth of the 

 flowering plants. At this rate, and assuming that on the higher ranges of these hills there are 

 1000 species of flowering plants which, including grasses and rushes I dare say is near the truth; 

 then there should be 33 species of Ruhiaceous plants. This may be somewhat beyond the truth, 

 but I rather think, including Stellatae, it is under the actual number now in my herbarium, which 

 however I have not counted. Assuming that these two estimates are each approximations to the 

 truth, they go far to show that the climate of the hills partake more of the tropical character 

 than some of the examples previously adduced would lead us to expect, and that although an 

 immense improvement on that of the plains, we must still view it as very inferior to even the 

 South of Europe, as a temperate climate, unless it can be shown that the temperature is modified 

 in its effects on the constitution by our very rarified atmosphere, requiring a greater volume of 

 air, by probably nearly i, to be respired to yield the same quantity of oxygen to the circulation, 

 that would be obtained in a similar temperature on the level of the sea. This is not the place to 

 consider what effect this difference may have in modifying health and disease, though it seems 

 quite in place to direct attention to the circumstance in connection with facts deduced from a 

 consideration of the natural products of the region." 



The subject here adverted to is one which I am of opinion has not received the attention, in 

 a purely medical point of view, it seems to merit, which is my reason for alluding to it here 

 in a work professedly in a great measure medical, and which is in the hands of so many of the 

 profession. 



DeCandolle has distributed about 1600 species described in his Prodromus under 13 tribes* 

 Species referable to 10 of these appertain to the Flora of India and the Eastern Islands, a fact 

 showing both the richness of our flora in this family, and its marked tropical tendency. I have 

 not ascertained the relative proportion which the Indian ones bear to those of the rest of the 

 world, but I presume it is at least equal to that of America, and greatly in excess of what has 

 been found elsewhere. From these facts, combined with the similarity of climate in which the 

 Cinchonas of America is found as compared with many of the Alpine climates of India, Dr. 

 Royle suggests the propriety of attempting their introduction into India. The proposal seems 

 feasible enough, and, considering the vast quantities of Bark and Quinine annually consumed in 

 India, it seems well deserving of a trial and, if successful, would unquestionably be conferring a 

 vast boon on India, as none of our native products, so far as yet known, can be considered a sub- 

 stitute. Many plants have been tried as substitutes, but hitherto with very indifferent success. 



PuoPERTiEs AND UsES. It has becu remarked above that this, in its economical relations, 

 is a most important family. To it we are indebted for the justly-famed Peruvian Bark. 

 Bitterness and astringency are properties very extensively met with in this family, more or 



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