1834.] 



Observations on Botany, ^c. 



326 



great classes, acotyledones, monocotyledones, and dicotyledones. 

 The first class or flowerless plants, includes the whole of the Linnean 

 class Cryptogamia ; the other two, or flowering plants, embrace the 

 remaining 23 classes of that system. Supposing it were wished to 

 ascertain the relative proportion these classes bear to each other, 

 either with respect to the vegetation of the whole globe, or any given 

 portion of it, we divide the number of flowering by the number of 

 the flowerless plants and the quotient is the proportion required. 

 The proportion a particular family or genus bears to the flora of a 

 country or of the globe can be thus ascertained, and many, other 

 questions answered which we have not room to particularize. Hum- 

 bolds estimates in this way, that the proportion of the flowerless to 

 flowering plants within the tropics is 1 to 9; in the temperate zone, 1 

 to 4; and in the frozen, that they are equal. The proportion of 

 Mono-to Di cotyledones, is estimated at 1 to 5 or 6 within the 

 tropics ; 1 to 4 in the temperate ; and 1 to 3 in the frozen zone. Of 

 Dicotyledonous orders, Legumenosoe are said to bear to the whole 

 flowering plants the proportion within the tropics, of 1 to 12; 

 in America; 1 to 9 in India; ^; in New Holland; -J; in western 

 Africa. Temp. Zone. France -jig- ; Germany ; ; north America 

 ^; Siberia ; Sweden -jL-'» Sicily ^; Frozen Zone -^-j. Melville 

 island These examples are enough to show the general prin- 



ciple, which can be followed out to any extent. The Flora of a 

 district can thus be compared with that of the whole country, 

 or with another district; that of the plains with the hills; of the 

 sea coast with the inland districts &c. and may ultimately when 

 the relation between soils and plants* are better known, lead to 

 the most important results. Let us now devote a few lines to the 

 analysis of the Indian flora according to this rule. Estimating the 

 known flowering plants of the globe at 70,000, and those of In- 

 dia at 9000, gives for India within a fraction of ; supposing 

 again that there are 800 Indian species of Leguminosae, gives the 

 proportion, -j\ for the whole flora; -gL| for the globe: suppos- 

 ing again that there are 4000J Leguminosoe scattered over the 

 globe, those of India are to those of the globe as ^; this kind of 

 analysis is equally applicable to every order and genus. 



We are aware, that in taking 9000 as the amount of the 

 Indian flora, we fall far short of Dr. Wallich's calculation, which, 

 we learn from the article Botany of The description of India" 



• On this subject see Mr. Brown's very interesting paper in the Transac- 

 tions of the Geographical Society ; a paper, which we regret we had not 

 seen, when these observations went to press. 



