III.— B T AN Y 



Art. XXXIII. — On the Fei-tilizatioii, etc., of New Zealand Flowering Plants. 



By Geokge M. Thomson, F.L.S. 



[Bead before the Otago Institute, llth May, 1880.] 



Plate X. 

 The collection and examination of the flowering plants of this colony have 

 occupied a good deal of my spare time during the last four or five years, 

 and have enabled me to accumulate some materials for working out the 

 various modes of fertihzation which are to be found among them. These 

 materials, even when made the most of, are however only sufficient to show 

 how little is really known of this most interesting subject. In giving, 

 then, the results of my imperfect observations, I do so in the form of a pre- 

 liminary notice, which I trust will pave the way for fuller and more detailed 

 work in the future. This subject of the fertilization of our flowering plants 

 is necessarily so mixed up with the question of our insect fauna that I am 

 led to unite the two to a certain extent, and show the relationship which 

 exists between them. 



At the risk of repeating to many here information which they already 

 possess, I will — for the benefit of the uninitiated — shortly explain the 

 phenomena of fertilization of flowering plants, as far as external manifesta- 

 tions are concerned. The sexual organs of such plants are contained in 

 those parts of the flower termed, respectively, stamens and pistil. A stamen 

 consists essentially of a 1-, 2-, or 4-celled cavity, called the anther (which 

 may or may not be mounted on a stalk, or filament), and which contains, 

 usually, a vast number of small, variously-shaped, cellular bodies, the 

 pollen-grains, which either are themselves, or contain, the male fertihzing 

 element. The pistil consists of a 1- or more-celled cavity, the ovary, con- 

 taining ovules, in which the female element occurs. External to the ovary 

 is a glandular portion (of extremely various shapes in various plants), 

 termed the stigma, which at a certain stage of the development of the 

 flower becomes viscid, and so fitted to catch and retain the pollen-grains. 

 In some cases the stigma is on a stalk, the style, in others it is sessile. The 

 pollen-grains, when in contact with and apparently excited by the viscid 

 secretion of the stigma, produce very slender tubes which grow down and 

 penetrate the ovary, and finding their way to the micmpyles (or apertures) 



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