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XXIX. Descriptions of Indian Gentianeae. By David Don, Esq., Libr. L.S., 



Prof. Bot. King's Coll. Lond. 



Read November 3rd and 17 th, 1835. 



Among the numerous families which compose the class of Dicotyledonous 

 plants there is, perhaps, none so equally and generally distributed over the 

 surface of the globe as the Gentiunece, for they are found dispersed throughout 

 the greater part of both hemispheres ; and this observation applies not to the 

 entire family only, but likewise to many of the smaller groups, as may be seen 

 by consulting the table which precedes the descriptive part of this paper. 



In comparing the Floras of different countries, we shall find that what has 

 been just stated with respect to their equal distribution is fully borne out by 

 facts, at least in the Northern hemisphere, whose vegetable riches have been 

 more completely investigated, and that they form about the proportion of -gVth 

 of the phaenogamous vegetation. In the Swiss Flora, which comprises 2000 

 phsenogamous plants, 26 are of this family; in the Siberian Flora, of 170O 

 phaenogamous plants, 21 are Gentianeoe; in that of the Caucasus and Crimea, 

 in 2000 there are 20 ; in Peru and Quito, the phaenogamous plants of which 

 may be estimated at 4500, there are 43 Gentianeoe ; and in the North Ame- 

 rican Flora there are 55 out of 4081 phaenogamous plants. 



By the indefatigable researches of Dr. Wallich and Dr. Royle, the number 

 of species of this family belonging to the Indian Flora has been more than 

 doubled, and they now amount to about 50. Of the 14 genera into which 

 they have been distributed, Canscora, Exacum, Slevogtia, Crawfurdia, Ophelia, 

 and Agathotes are exclusively Indian, and the remaining 7 are common also 

 to the European and Northern Asiatic Floras. Of these 50 species, 34 belong 

 to the Alpine Flora, which in 3500, the number at which the phaenogamous 

 plants of the Flora of Northern India may be estimated, will give a larger pro- 

 portion than that above mentioned. 



