Mutations in CultivatioH. 



195 



whose seeds seem to have no means of 

 becoming distributed. Lastly there are 

 the sterile varieties; Currants (Corin- 

 thian grapes), Bananas, many sorts of 

 apples and pears, astrakhan grapes, 

 some strawberries, the green rose, the 

 green Pelargonium sonale and green 

 Dahlias (of which I have cultivated 

 two different sorts, one with elongated 

 and the other with ordinary flat flower- 

 heads). Ranunciihis acris and Caltlia 

 palustris which have become sterile by 

 petalomany (Fig. 40) and many other 

 examples of this kind of doubling;^ 

 then there is the sterile Maize (Fig. 

 41) many examples of which have ap- 

 peared in my own cultures but which, 

 so far as I know, does not seem to 

 have been noticed elsewhere.^ 



The great majority of forms which 

 have arisen suddenly, be they varieties 

 or subspecies, come absolutely true 

 from seed; that is to say every single 

 seed gathered reproduces the new form 

 when sown, provided that the seed pa- 

 rent was fertilized w^ith its own pollen, 

 or with pollen from another example 

 of the same form. Constancy is one of 

 the properties of elementary species. 



^ K. GoEBEL. Pringsheim's Jahrhiichcr fiir 

 wissensch. Bot., Vol. XVII, p. 207. 



^ Over stericle Maisplanten, Botan. Jaarboek 



1889, Table V, p. 141. Steriele Mais als erfelyk 



1890, p. 109. 



Fig. 41. Zca Mays 

 sterilis. Three un- 

 branched "pan- 

 icles." a, without 

 bracts ; b and c. 

 with slight bract 

 formation at the 

 tip. 



Dodonaea, Vol. I, 

 ras, ibid.. Vol. y, 



