1862 i88i] MELASTOMADS 295 



sets of anthers (i.e. the petal-facers and the sepal-facers) have Letter 621 

 very different powers ; and it does not seem that the differ- 

 ence is connected with any tendency to abortion in the one 

 set. Now I think I can understand the structure of the 

 flower and means of fertilisation, if there be two forms, one 

 with the pistil bent rectangularly out of the flower, and the 

 other with it nearly straight. 



Our hot-house and green-house plants have probably all 

 descended by cuttings from a single plant of each species ; so 

 I can make out nothing from them. I applied in vain to 

 Bentham and Hooker ; but Oliver picked out some sentences 

 from Naudin, which seem to indicate differences in the position 

 of the pistil. 



I see that Rhexia grows in Massachusetts ; and I suppose 

 has two different sets of stamens. Now, if in your power, 

 would you observe the position of the pistil in different plants, 

 in lately opened flowers of the same age ? (I specify this 

 because in Monochcetum I find great changes of position in 

 the pistils and stamens, as flower gets old). Supposing that 

 my prophecy should turn out right, please observe whether in 

 both forms the passage into the flower is not [on] the upper 

 side of the pistil, owing to the basal part of the pistil lying 

 close to the ring of filaments on the under side of the flower. 

 Also I should like to know the colour of the two sets of 

 anthers. This would take you only a few minutes, and is the 

 only way I see that I can find out whether these plants are 

 dimorphic in this peculiar way i.e., only in the position of 

 the pistil 1 and in its relation to the two kinds of pollen. I 

 am anxious about this, because if it should prove so, it will 

 show that all plants with longer and shorter or otherwise 

 different anthers will have to be examined for dimorphism. 



To Asa Gray. Letter 622 



March I5th [1862]. 



... I wrote some little time age about Rhexia ; since then 

 I have been carefully watching and experimenting on another 

 genus, Monochcetum ; and I find that the pistil is first bent 



1 In Exacum and in Saintpaulia the flowers are dimorphic in this 

 sense : the style projects to either the right or the left side of the corolla, 

 from which it follows that a right-handed flower would fertilise a left- 

 handed one, and vice versa. See Willis, Flowering Plants and Ferns, 

 1897, Vol. I., p. 73. 



