DARWINISM 



remarkable facts as to their variability. He declares that on 

 the same branch of oak he has noted the following variations : 

 (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 

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

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

 blunt, 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 

 which 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 sepals, 

 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. 1 



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

 equal amount of variation occurs ; and I have myself gathered 

 1 Nature, vol. xxvi. p. 81. 



