Chap. VIII. IMPATIENS. 327 



we should remember that this is a naturalised species. 

 The perfect flowers are usually barren in England ; but 

 Professor Asa Gray writes to me that after midsummer 

 in the United States some or many of them produce 

 capsules. 



Impatiens noli-me-tangere. — I can add nothing of 

 importance to Von Mohl's description, excepting that 

 one of the rudimentary petals shows a vestige of a 

 nectary, as Mr. Bennett likewise found to be the ease 

 with /. fulva. As in this latter species all five stamens 

 produce some pollen, though small in amount; a 

 single anther contains, according to Von Mohl, not 

 more than 50 grains, and these emit their tubes 

 while still enclosed within it. The pollen-grains of 

 the perfect flowers are tied together by threads, but 

 not, so far as I could see, those of the cleistogamic 

 flowers; and a provision of this kind would here have 

 been useless, as the grains can never be transported 

 by insects. The flowers of 7. balsamina are visited by 

 humble-bees,* and I am almost sure that this is the case 

 with the perfect flowers of I. noli-me-iangere. From 

 the perfect flowers of this latter species covered with 

 a net eleven spontaneously self -fertilised capsules were 

 produced, and these yielded on an average 3.45 seeds. 

 Some perfect flowers with their anthers still containing 

 an abundance of pollen were fertilised with pollen from 

 a distinct plant; and the three capsules thus produced 

 contained, to my surprise, only 3, 2, and 1 seed. As 

 I. balsamina is proterandrous, so probably is the pres- 

 ent species ; and if so, cross-fertilisation was effected by 

 me at too early a period, and this may account for the 

 capsules yielding so few seeds. 



Drosera rotundifolia. — The flrst flower-stems which 



* H. MuUer, ' Die Befruchtnng,' &c. p. 170. 

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