292 THE JOUKXAL OF BOTANY 



LINNEAN SPECIES IN OUR DAYS. 

 Br Eexst Almquist, Professor emeritus, SfockJiolm. 



Nature itself has grouped a large proportion of living organisms 

 into units that are very easy to recognize. Their descendants remain 

 constant both in appearance and character, the distinguishing charac- 

 teristics of the different units being well-marked. Most of the 

 Linnean species are such units. 



Linne emphasizes that species are created by Nature and not by 

 tlie scientists. Many of them were well known before his time — 

 Kay described many ; but, as far as I know, it was Linne who first 

 pointed out the constancy of the " distinctions." He also proved this 

 constancy ; every year he sowed thousands of different forms from all 

 countries — not one species lost its characters (Transmutatio frument. 

 1757, p. 6). 



It is deplorable that Linne's experiments on species are not 

 thoroughly known. Biology still suffers from it. Only those facts 

 and theories are now remembered that his contemporaries, with the 

 spirit of that time, were able to understand and digest. The following 

 important facts are very often forgotten : — • 



1. Linne's species possess constant characters that do not change 

 in di:fferent environments. 



2. Some species Linne describes as collective sjjecies. De Vrios 

 points out that Linne did this intentionally, but his successors almost 

 forgot it. Thus Primula veris contains three constant sj^ecies, 

 named trinominally. 



3. Linne separated the varieties into two different groups, varie- 

 tafes ex loco and variefates constantes -, the former go back to the 

 common forms by culture, the latter do not (Metamorph. plantarum, 

 1755, p. 18). The constant varieties are innumerable : "dantur emm 

 innumerie v^arietates qua cultura non reducuntur, sed constantes per- 

 sistunt " (Flora suec. 1755, p. 247). The life of man is too short 

 for discerning the immense number : " fineni ludentis polymorphse 

 naturae, vix attingat botanicus " (Phil. bot. p. 249). 



The constant varieties may be considered as independent species ; 

 but very small differences, e.g. a])etaly or greater size of Hower, Linne 

 found not sufficient for creating new species (Metamorph plant, 

 p. 18). 



4. Some species are easy to recognize, but some forms are really 

 difficult or impossible to distinguish. In certain genera Linne gene- 

 rally found the species well linuted, but one group would contain an 

 excess of similar forms ; in some genera all forms were connected 

 closely. In the Species Plantarum Linne reserved pronouncement 

 on the species of Rosa, Salix, and the Fungi. He speaks of ''genera 

 prolixiora " or '• difusiora " — the American Quercus, Aster, Passi- 

 Jlora, Cactus, the African Geranium, Mesemhryanthemum (Plantie 



hvbr. 1751, pp. 6, 29). He suspected that the varieties of Tulipa, 

 Brassica, Lactiica, Pyrus, etc., originated by crosses (Fundamentum 

 fructiticat. 1762, p. 21). 



5. Part of the last-named varieties, e. g. tlie cultivated kinds of 

 Brassica, Linne. compares v.ith the strains of the dog. Like the 



