i868-iS8i] CORONILLA 393 



in the staminal tube, and the opening caused by the free stamen enables 

 the bee to reach the nectar, and in so doing the bee fertilises the plant. 

 In Coronilla varia, and in several other species of Coronilla, there is no 

 nectar in the staminal tube or in the tube of the corolla. But there are 

 peculiar glands with nectar on the outside of the calyx, and peculiar 

 openings in the tube of the corolla through which the proboscis of the 

 bee, whilst entering the flower in the usual way and dusting itself with 

 pollen, can reach these glands, thus fertilising the plant in getting the 

 nectar. On writing this to Mr. Darwin, I received the following 

 characteristic note. 



The first postscript relates to the rough ground behind my house, 

 over which he was fond of strolling. It had been ploughed up and then 

 allowed to go back, and the interest was to watch how the numerous 

 species of weeds of cultivation which followed the plough gradually gave 

 way in the struggle for existence to the well-known and much less varied 

 flora of an English common." 



Bassett, Southampton, Aug. I4th, 1873. 



You are the man to conquer a Coronilla. 1 I have been Letter 715 

 looking at the half-dried flowers, and am prepared to swear 

 that you have solved the mystery. The difference in the size 

 of the cells on the calyx under the vexillum right down to 

 the common peduncle is conspicuous. The flour still adhered 

 to this side ; I see little bractese or stipules apparently with 

 glandular ends at the base of the calyces. Do these secrete ? 

 It seems to me a beautiful case. When I saw the odd shape 

 of the base of the vexillum, I concluded that it must have 

 some meaning, but little dreamt what that was. Now there 

 remains only the one serious point viz. the separation of the 

 one stamen. I daresay that you are right in that nectar was 

 originally secreted within the staminal tube ; but why has not 

 the one stamen long since cohered ? The great difference in 

 structure for fertilisation within the same genus 2 makes one 

 believe that all such points are very variable. With respect 

 to the non-coherence of the one stamen, do examine some 

 flower-buds at a very early age ; for parts which are largely 

 developed are often developed to an unusual degree at a very 

 early age, and it seems to me quite possible that the base of 

 the vexillum (to which the single stamen adhered) might thus 

 be developed, and thus keep it separate for a time from the 



1 In a former letter to Lord Farrer, Darwin wrote : " Here is a maxim 

 for you, ' It is disgraceful to be beaten by a Coronilla? ' 



2 Coronilla emerus is of the ordinary papilionaceous type. 



