24^ Transactions. — Botany. 



of the ovules, bring about fertilization. Into this part of the subject I do 

 not propose to enter, but will confine myself to the modes in which the pol- 

 len is transferred to the stigma. In a very large number of species, both 

 stamens and pistil occur in the same flower, which is then said to be her- 

 majjhrodite. In other species, the stamens and pistil are in separate flowers, 

 which are then iinisexual. Unisexual plants are moncecious when the stami- 

 nate and pistillate flowers are on the same plant, as in Carex, etc., and 

 dkecious when they are on different plants, as in Coprosma. Lastly, some 

 plants, as manuka fLejjtosjMi-mum scoparium), produce both hermaphrodite 

 and unisexual flowers, and are then said to be poh/f/amous. 



At first sight it would seeem as if all hermaphrodite flowers were self- 

 fertilized, i. e. that the pollen from the anthers became transferred to the 

 stigma of the same flower, and so brought about fertilization. On examina- 

 tion, however, it is found that this is not always the case ; in fact it would 

 seem not to be the case in a majority of instances. By a multiplicity of 

 means and contrivances it happens that many hermaphrodite flowers can- 

 not be self-fertilized, but are dependent upon the pollen of other flowers, 

 which may be brought to them in various ways. Unisexual flowers of 

 course are always dependent on other flowers for their fertilization. The 

 two great agents wdiicli carry out this cross-fertilizing process are insects 

 and the wind, and plants are termed entomophilous or anemop)hilovs, accord- 

 ing as they are dependent on one or the other agency. Some birds (chiefly 

 tuis and honey-birds in New^ Zealand) aid in the process, but only seven or 

 eight species of Otago flowers are fertilized by them. (The following are the 

 species with which I am acquainted, wdiich are thus visited and aided: — 

 Clianthus jnmiceus, Sophora fetraptera, Metrosideros lucida, Fuchsia excorticata, 

 etc. Loranthus colensoi (?), Dracoj^hj/Uum longifolium occasionally, and 

 Phormium tenax. Probably there are others.) 



It is hardly worth while to discuss here and now the 2yi'os and co77s of the 

 theory first enunciated by Sprengel, but only fully explained by Darwin and 

 his followers — that the characteristic features of each species of plant and 

 animal have been acquired during a long " struggle for existence," and are 

 the result of the adaptation of the species to its environments. It is suffi- 

 cient to affirm that it is now held by most biologists that the colom*, odour, 

 and honey of flowers are designed to attract insects, and have been produced 

 in accordance with the law of the survival and accumulation of favourable 

 variations. Other flowers not furnished with these means of attraction 

 have been developed into their present forms by the gradual production of 

 certain other characters favouring their fertilization by wind, until they 

 have become strictly anemophilous. In New Zealand "vve seem to see the 

 transition stage to this state of things taking place among some species. 



