278 VIEWS, &C. PHYSIOGNOMY OF PLANTS. 



which I purpose developing more fully at the close of this 

 illustration, seem to verify the ancient myth of the Zend- 

 Avesta, that "the creating primeval force called forth 120,000 

 vegetable forms from the sacred blood of the bull." 



If therefore no direct scientific solution can be afforded to 

 the question, how many vegetable forms leafless cryptogamia 

 (water algae, fungi, and lichens), characea3, liverworts, folia- 

 ceous mosses, marsilacese, Iycopodiacea3, and ferns exist on 

 the dry land, and in the wide basin of the sea, in the present 

 condition of the organic terrestrial life of our planet, it only 

 remains for us to employ an approximative method for ascertain- 

 ing with some degree of probability certain "extreme limits" 

 (numerical data of minima). Since the year 1815, I have, 

 in my arithmetical considerations on the geography of plants, 

 calculated the numbers expressing the ratio which the aggre- 

 gate of species of different natural families bears to the whole 

 mass of the phanerogamia in those countries where the latter is 

 sufficiently determined. Robert Brown,* the greatest botanist 

 of our age, had, prior to my researches, already determined 

 the numerical proportion of the principal divisions of vegetable 

 forms, as for instance of acotyledons (Agamce, cryptogamic or 

 cellular plants) to cotyledons (Phanerogamia, or vascular 

 plants), and of monocotyledons (Endogena] to dicotyledons 

 (Exogence). He finds the ratio of monocotyledons to dicotyle- 

 dons in the tropical zone as in the proportion of 1 to 5, and 

 in the frigid zone, in the parallels of 60 north, and 55 south 

 lat. as 1 to 2j.f The absolute numbers of the species are 

 compared together in the three great divisions of the vegetable 

 kingdom, according to the method developed in Brown's work. 

 I was the first who passed from these principal divisions to 

 the individual families, and considered the number of the 

 species contained in each, in their ratio to the whole mass 

 of phanerogamia belonging to one zone.| 



* Formerly librarian to Sir Joseph Banks, now President of the 

 Linnsean Society. ED. 



*f- Robert Brown, General remarks on the botany of Terra Australia, 

 in Flinders' Voyage, vol. ii. p. 338. 



J Compare my essay, De distributione geographica Plantarum 

 secundum cceli temperiem et altitudmem montium, 1817, pp. 24 44; 

 and see the farther development of numerical relations as given by me 

 in the Dictionnaire des Sciences naturelles, t. xviii. 1820, pp. 422 

 436; and in the Annales de Chimie et de Physique, t. xvi. 1821, 

 pp. 267292. 



