356 THE POPULAR SCIENCE MONTHLY 



University. That he collected assiduously at times during portions of 

 this expedition, is evidenced by his having brought home specimens of 

 193 species of the 225 species which, after his specimens had been 

 studied, were known to inhabit the Galapagos Islands and by the fact 

 that about 100 species new to science were represented in his Galapagos 

 collection. He noticed the extraordinary distribution of species or 

 races on the several islands of this group, many of them inhabiting 

 only a single island, and he laid the foundation for all subsequent study 

 of insular floras. The narrative of observations and experiences during 

 this memorable voyage is replete with interesting facts and suggestions 

 concerning plants, and his conclusion that "Nothing can be more 

 improving to a young naturalist than a journey in distant countries," 

 is one that should be reiterated by all teachers of natural science, and 

 such experience should be sought by all students who propose engaging 

 in investigation. Darwin is commemorated in botanical taxonomy by 

 many species named in his honor. The beautiful barberry, Berheris 

 Darwinii of Hooker, native of Chiloe, is occasionally seen in cultivation. 

 Darwinia, an Australian genus of the myrtle family, named by Eudge 

 in 1813, commemorates his grandfather, Erasmus Darwin. 



The beginnings of Darwin's theory of descent of animals and plants 

 from preexistent species, with modifications, were made during the 

 voyage of the Beagle, and from the year after his return to England, 

 when, he tells us, he opened the first note-book on the subject. For 

 twenty-two years he was interrogating gardeners and breeders, botanists 

 and zoologists, and diligently observing plants and animals. He first 

 thought of publishing on the theory of descent in 1839, but delayed for 

 twenty years. During the studies which led up to the publication, in 

 1859, of " The Origin of Species by Means of Natural Selection, or the 

 Preservation of Favored Eaces in the Struggle for Life," Darwin closely 

 observed a great number of wild and cultivated plants, with reference 

 to variation in nature and under domestication, the struggle for exist- 

 ence due to competition for food and sunlight, the facts of geographic 

 distribution, the succession of plant life on the earth as indicated by 

 the fossils of successive geologic periods, and a great range of other 

 facts and phenomena. The recorded observations of other botanists 

 were also freely utilized and discussed. Nearly all the chapters of this 

 epoch-making work contain conclusions drawn from his own botanical 

 observations. He was especially impressed by the divergent views of 

 different botanists relative to the taxonomic treatment of highly poly- 

 morphic genera such as Hieracium (hawk- weeds), Ruhus (blackberry), 

 Quercus and Rosa, and he employed this consideration to great advan- 

 tage in his argument for derivation during descent. Eudimentary 

 organs were considered with much interest and readily explained by 

 Darwin as vestiges of structures which were useful to the plant in 



