CHAP. V. 



SPECULARIA SPECULUM. 



175 



showed that the former were probably the most productive. Jt 

 appears that this plant is capable of producing a large number 

 of self-fertilised capsules owing to the petals closing at night, as 

 well as during cold weather. In the act of closing, the margins 

 of the petals become reflexed, and their inwardly projecting 

 midribs then pass between the clefts of the stigma, and in doing 

 so push the pollen from the outside of the pistil on to the 

 stigmatic surfaces.* 



Twenty flowers were fertilised by me with their own pollen, 

 but owing to the bad season, only six capsules were produced ; 

 they contained on an average 21 '7 seeds, with a maximum of 

 forty-eight in one. Fourteen flowers were crossed with pollen 

 from another plant, and these produced twelve capsules, contain- 

 ing on an average 30 seeds, with a maximum in one of fifty- 

 seven seeds ; so that the crossed seeds were to the self-fertilised 

 from an equal number of capsules as 100 to 72. The former 

 were also heavier than an equal number of self-fertilised seeds, 

 in the ratio of 100 to 86. Thus, whether we judge by the number 

 of capsules produced from an equal number of flowers, or by the 

 average number of the contained seeds, or the maximum number 

 in any one capsule, or by their weight, crossing does great good 

 in comparison with self-fertilisation. The two lots of seeds were 



TABLE LXVII. 



Specularia speculum. 



* Mr. Meehan has lately shown 

 ( Proc. Acad Nat. So. Philadel- 

 phia,' May 16, 1876, p. 84) that 

 the closing of the flowers of Clay- 



tonia virginica and Ranunculus but- 

 bosus during the night causes their 

 self-fertilisation. 



