PLANT HYBRIDIZATION BEFORE MENDEL 81 



ture consequently spent itself in intractable and dictatorial con- 

 tentions. 



Of his botanical knowledge, gained during his Spandau studies, 

 his contemporary, Willdenow, afterward the first professor of 

 botany in the University of Berlin, made use in his "Prodromus 

 Florae Berolinensis," 1787, and praised the self-taught botanist 

 as "a thoroughly keen-minded plant investigator." 



The discoveries of Christian Konrad Sprengel should have 

 called attention to Kolreuter's antecedent discovery of the relation 

 between insects and flowers. While Camerarius had demonstrated 

 the fact that plants possess sex, and Kolreuter had shown that 

 fertile hybrids could be produced between plants of different 

 kinds, the further fact, that crossing in nature, at least among 

 different individuals of the same species, is a common and ordi- 

 nary phenomenon in the plant kingdom, was not at all known. 

 Aware, as we are today, that the improvement of cultivated plants, 

 due to the appearance of new strains and varieties, is to be ac- 

 credited largely at the outset to the natural crossing of individuals 

 standing in fairly close genetic relationship to one another, we 

 can see the great importance, in the history of plant breeding, of 

 Sprengel's discovery that flowers are commonly pollinated by 

 insects, and that there is an intimate interrelationship between the 

 plant and the insect worlds, 



Sprengel's epoch-making book "The Newly-revealed Secret of 

 Nature in the Structure and Fertilization of Flowers" fii) con- 

 stitutes a third great landmark in plant breeding, after the orig- 

 inal discovery of the possibility of artificial pollination by the 

 Mesopotamian date growers. Such a wealth of accurate first-hand 

 observations on the adaptations of flowers to cross-pollination 

 had never before been made. To Sprengel also is due the discov- 

 ery of dichogamy, i,e., the maturing of the stamens and the pis- 

 tils of flowers at different times. His conclusion, that nature in 

 most cases intended that flowers should not be fertilized by their 

 own pollen, and that the peculiarities of flower structure can only 

 be understood when studied in relation to the insect, was revolu- 

 tionary for his time. 



Sprengel's work has been well described by Sachs, as "the first 

 attempt to explain the origin of organic forms from definite rela- 

 tion to their environment." (9, p. 415-) 



