, 1S81] F. M i l.i 365 



nearly in the zenith; but I doubt whether this parahelio- Lette - - 

 tropisra will be observable in E d. To-day, though con- 



tinuing to be fully exposed to the sun, at 3 p.m. the leaves 

 had aliead\- returned to a nearly horizontal position. As soon 

 as there arc ripe seeds I will send you some; of our other 

 species of Phyllantkus I enclose a few seeds in this letter. 



In several species of Hedychium the lateral halves of the 

 leaves when exposed to bright sunshine, bend downwards 

 that the lateral margins meet. It is curious that a hybrid 

 Hedychium in my garden shows scarcely any trace of this 

 paraheliotropism, while both the parent species are very 

 parahcliotropic. 



Might not the inequality of the cotyledons of Citrus and 

 of Pachira be attributed to the pressure, which the several 

 embryos enclosed in the same seed exert upon each other? 

 I do not know Pachira aquatica, but [in] a species, of which 1 

 have a tree in my garden, all the seeds are polyembryonic, 

 and so were almost all the seeds of Citrus which 1 examined. 

 With Coffea arabica also seeds including two embryos are 

 not very rare ; but I have not yet observed whether in this 

 case the cotyledons be inequal. 



I repeated to-day Duval-Jouve's measurements ' on Bryo- 

 phyllum calycinum ; but mine did not agree with his ; they 

 are as follows : — 



Distances between the tips of the upper pair of lea^ 



Down, Feb. 23rd, 1881. 



Your letter has interested me greatly, as have so many 

 during many past years. 1 thought that you would not 



1 Power of Movement in Plants, p. 237. F. Mutter's measurements 

 show, however, that there i-- a tendeni y in the leaves to be men' highly 

 inclined at night than in the middle of the day, and so tar they , ; . 

 with Duval-Jouve's results. 



