304: GYNO-DICECIOUS PLANTS. Chap. VII. 



that the females produce many more seeds than the 

 hermaphrodites, increased fertility seems to me the 

 more probable cause of the formation and separation of 

 the two forms. From the data above given it follows 

 that ten plants of Thymus serpi/llum, if half consisted 

 of hermaphrodites and half of females, would yield 

 seeds compared with ten hermaphrodite plants in the 

 ratio of 100 to 72. Under similar circumstances the 

 ratio with Satureia hortensis (subject to the doubt from 

 the self -fertilisation of the hermaphrodite) would be as 

 100 to 60. Whether the two forms originated in cer- 

 tain individuals varying and producing more seed than 

 usual, and consequently producing less pollen; or in 

 the stamens of certain individuals tending from some 

 unknown cause to abort, and consequently producing 

 more seed, it is impossible to decide; but in either 

 case, if the tendency to the increased production of 

 seed were steadily favoured, the result would be the 

 complete abortion of the male organs. I shall pres- 

 ently discuss the cause of the smaller size of the female 

 corolla. 



Scdbiosa arvensis (Dipsacese). — ^It has been shown by 

 H. Mtiller that this species exists in Germany under an 

 hermaphrodite' and female form.* In my neighbourhood 

 (Kent) the female plants do not nearly equal in number 

 the hermaphrodites. The stamens of the females vary 

 much in their degree of abortion ; in some plants they are 

 quite short and produce no pollen ; in others they reach to 

 the mouth of the corolla, but their anthers are not half 

 the proper size, never dehisce, and contain but few pollen- 

 grains, these being colourless and of small diameter. The 



* ' Befruehtiing der Bluraen,' males co-exist ; it is, however, 



&o., p. 368. The two forms occur possible that he may have been 



not only in Germany, but in deceived by the flowers being so 



England and France. Lecoq strongly proteiandrous. From 



(!&6ogra.phie Bot.' 1857, torn. vi. what Lecoq says, R jhccmo likowiso 



pp. 473, 477) says that male plants appears to occur under two forms 



as wpll as hermaphrodites and fe- in Fiance. 



