CHAP. IV. OXALIS EEGNELLI. 173 



ered plants of the three forms growing near together 

 failed to produce fruit. 



Oxalis Regnelli. This species bears white flowers 

 and inhabits Southern Brazil. Hildebrand says that 

 the stigma of the long-styled form is somewhat larger 

 than that of the mid-styled and this than that of the 

 short-styled. The pistil of the latter is clothed with a 

 few hairs, whilst it is very hairy in the other two 

 forms. The diameter of the pollen-grains from both 

 sets of the longest stamens equals 9 divisions of the 

 micrometer, that from the mid-length stamens of the 

 long-styled form between 8 and 9, and of the short- 

 styled 8, and that from the shortest stamens of both 

 sets 7. So that the extreme difference in diameter is 

 as 9 to 7, or as 100 to 78. The experiments made by 

 Hildebrand, which are not so numerous as in the last 

 case, are given in Table 28 in the same manner as 

 before. 



The results are nearly the same as in the last case, 

 but more striking; for 41 flowers belonging to the 

 three forms fertilised legitimately all yielded capsules, 

 containing on an average 10.31 seeds; whilst 39 

 flowers fertilised illegitimately did not yield a single 

 capsule or seed. Therefore the fertility of the six 

 legitimate to that of the several illegitimate unions, 

 as judged both by the proportion of flowers which 

 yielded capsules and by the average number of con- 

 tained seeds, is as 100 to 0. 



Oxalis speciosa. This species, which bears pink 

 flowers, was introduced from the Cape of Good Hope. 

 A sketch of the reproductive organs of the three 

 forms (Fig. 11) has already been given. The stigma 

 of the long-styled form (with the papilla on its sur- 

 face included) is twice as large as that of the short- 

 styled, and that of the mid-styled intermediate in size. 



