78 DARWINISM 



remnrkable facts as to their variability. He declares that on 

 the same branch of oak he has noted the following vai'iations : 

 (1) In the length of the petiole, as one to three ; (2) in the form 

 of the leaf, being either elliptical or obovoid ; (3) in the margin 

 l)eing entire, or notched, or even pinnatifid ; (4) in the ex- 

 tremity being acute or blunt ; (5) in the base being sharp, 

 l)lunt, or cordate ; (6) in the surface being pubescent or 

 smooth ; (7) the perianth varies in depth and lobing ; (8) 

 the stamens vary in number, independently ; (9) the anthers 

 are mucronate or blunt; (10) the fruit stalks vary greatly 

 in length, often as one to three; (11) the number of fruits 

 varies; (12) the form of the base of the cup varies ; (13) the 

 scales of the cup vary in form; (14) the proportions of the 

 acorns vary ; (15) the times of the acorns ripening and falling 

 vary. 



Besides this, many species exhibit well-marked varieties 

 Avhich have been described and named, and these are most 

 numerous in the best-known species. Our British oak (Quercus 

 robur) has twenty -eight varieties ; Quercus Lusitanica has 

 eleven ; Quercus calliprinos has ten ; and Quercus coccifera 

 eight. 



A most remarkable case of variation in the parts of a 

 common flower has been given by Dr. Hermann Miiller. He 

 examined two hundred flowers of Myosurus minimus, among 

 which he found thirty-five different proportions of the sej^als, 

 petals, and anthers, the first varying from four to seven, the 

 second from two to five, and the third from two to ten. Five 

 sepals occurred in one hundred and eighty-nine out of the two 

 hundred, but of these one hundred and five had three petals, 

 forty-six had four petals, and twenty-six had five petals ; but 

 in each of these sets the anthers varied in number from three 

 to eight, or from two to nine. We have here an example of 

 the same amount of " independent variability " that, as we 

 have seen, occurs in the various dimensions of birds and 

 mammals ; and it may be taken as an illustration of the kind 

 and degree of variability that may be expected to occur 

 among small and little specialised flowers.^ 



In the common wind-flower (Anemone nemorosa) an almost 

 equal amount of variation occurs ; and I have myself gathered 

 ^ Nature, vol. xxvi. p. 81. 



