192 BOTANY PART i 



The Mistletoe (Fiscum album), belonging to the Loranthaceae as do many 

 similarly parasitic exotic forms, possesses good-sized leaves, but reduced roots; 

 it is so well provided with chlorophyll as to be able to manufacture all the carbo- 

 hydrates it requires. 



II. Organs of Reproduction ( 93 ) 



A. Significance of Reproduction to the Organism. A natural 

 or an accidental death is the end of every organism. For the mainten- 

 ance of living beings reproduction is thus as essential as nutrition. 

 The main feature of reproduction lies in portions of an individual 

 continuing after its death, with the power of developing into new 

 individuals. On account of the possibility of accidental death, repro- 

 duction takes place before this occurs naturally, and usually involves 

 the formation of special germs, which separate from the parent plant 

 and, repeating the development of this, grow into new individuals. 



In most plants a division of labour is apparent between the vegeta- 

 tive and reproductive organs. This becomes more striking in the 

 more highly organised forms, in which an increasing number of parts 

 co-operate in reproduction. 



B. General Properties of the Germs. The construction of the 

 germs, as in the case of the vegetative organs, is closely connected 

 with the purposes they have to serve. 



The small size of most reproductive bodies, in comparison to 

 the vegetative organs, is characteristic. The parent plant can thus* 

 produce numerous germs without excessive expenditure of material, 

 while at the same time the distribution of the germs is facilitated. 



The object of reproduction is not merely the production of a new 

 individual in place of the parent, but an increase in the number of 

 individuals. Since the majority of the germs may not meet with 

 favourable conditions for their germination and growth, and a large 

 number will perish before they can in turn reproduce, the pro- 

 duction of only a single germ would result in the speedy extinction 

 of the species. An apparently prodigal production of germs is thus 

 the rule. A cap-fungus or a fern may form millions of spores ; a 

 poplar tree, according to BESSEY, may ripen twenty-eight million 

 seeds annually. 



Provision is further necessary for the separation of the germs 

 from the parent and their dispersal widely from it. In the immediate 

 neighbourhood there may not be the conditions for germination, or 

 there may be no room for the development of the progeny. 



Lastly, it is necessary for the germs to be provided with reserve 

 food materials from the parent organism, in order that their develop- 

 ment, until they are able to nourish themselves, should be ensured. 



Frequently the reproductive bodies serve to carry the organism 

 over cold or dry periods that are unfavourable to active life. They 



