290 VIEWS, &.C. PHYSIOGNOMY OE PLANTS. 



of Phanerogamia simultaneously cultivated in all the botanical 

 gardens of Europe at 20,000, we shall find, as they appear to 

 constitute about the eighth part of those already described 

 and contained in herbariums, that the whole number of 

 Phanerogamia must amount to nearly 160,000. This esti- 

 mate need not be regarded as too high, since scarcely the 

 hundredth part of many of the larger families, as, for instance, 

 Guttiferce, Malpighiacese, Melastomeae, Myrtaceae, and Ru- 

 biaceae, belong to our gardens." If we take the number 

 (26,660 species), given in Loudon's " Hortus Britannicus," 

 as the basis, we shall find, from the well-grounded series 

 of inferences drawn by Professor Kunth, and which I borrow 

 from his manuscript notice above referred to, that the esti- 

 mate of 160,000 will increase to 213,000 species; and 

 even this is still very moderate, since Heynhold, in his 

 " Nomenclator botanicus hortensis" (1846), estimates the 

 species of Phanerogamia already cultivated at 35,600. On 

 the whole, therefore, — and the conclusion is, at first sight, 

 sufficiently striking, — the number of species of Phanerogamia 

 at present known by cultivation in gardens, by descriptions, 

 and in herbariums, is almost greater than that of known 

 insects. According to the average estimates of several of 

 the most distinguished entomologists, whose opinion I have 

 been able to obtain, the number of insects at present described, 

 or contained in collections without being described, may be 

 stated as between 150,000 and 170,000 species. The rich 

 collection at Berlin contains fully 90,000, among which there 

 are about 32,000 beetles. Travellers have collected an im- 

 mense quantity of plants in remote regions, without bring- 

 ing with them the insects living upon them, or in the neigh- 

 bourhood. If, however, we limit these numerical estimates 

 to a definite portion of the earth's surface that has been the 

 best explored in regard to its plants and insects, as, for 

 instance, Europe, we find the ratio between the vital forms 

 of Phanerogamic plants and those of insects changed to such 

 a degree, that while Europe counts scarcely 7000 or 8000 

 Phanerogamia, more than three times that number of Euro- 

 pean insects are at present known. According to the interest- 

 ing contributions of my friend Dohrn in Stettin, more than 

 8700 insects have already been collected from the rich fauna 

 of the neighbourhood, and yet there are still many Micro- 



