138 BRITISH PLANTS 



protective mimicry. Others are bitter and unpalatable, 

 some are even poisonous e.g., seeds of laburnum, bitter 

 almonds, and nux vomica. 



2. The Protection of the Seedling. The seedling is 

 exposed to many dangers, many hardships, and countless 

 enemies. Nevertheless, though many perish, some sur- 

 vive. At the same time, plants when very young show 

 less in the way of protective devices than at any other 

 period of their existence. In most cases they survive by 

 sheer force of numbers. In seedlings, indeed, we do not 

 look for much in the way of defensive equipment apart 

 from a good constitution, and this seems all that is 

 necessary. The early stages of germination are carried 

 on below ground. This in itself is a protection to the 

 seedling in its youngest and most helpless condition ; it is 

 sheltered by the soil above it from wind and weather, and 

 concealed from the observation of a host of predatory 

 foes. 



3. The Adult Plant. The soft and nourishing tissues of 

 plants, besides being delicate and subject to injury from 

 weather, are exposed to a multitude of living enemies of 

 all kinds animals, insects, parasites, and diseases. An 

 ordinary tree e.g., the oak is the prey of countless foes. 

 Insects deposit their eggs within its soft tissues. From 

 these eggs arise destructive pests in the form of voracious 

 grubs and hungry caterpillars, which devour everything 

 within their reach. Some attack the stems and leaves, 

 others the roots, others the flowers. The bite of insects 

 and the deposition of eggs beneath the skin lead to the 

 formation of unsightly galls, which, while they provide 

 food for the subsequent grubs, at the same time circum- 

 scribe the limits of their damage. Fungi are still more 

 formidable enemies, and to them the majority of plant- 

 diseases is due. No one can have failed to observe the 

 damage caused by these parasites. Seedlings rot and 

 perish ; spots and tumours appear upon the leaves and 

 shoots of trees ; fungal outgrowths disfigure the branches. 

 Even the flowers are not exempt from injury. The 

 anthers may be filled with black smut instead of pollen, 

 and the ovary filled with grubs instead of ovules. 



Lastly, fresh green leaves and shoots, turgid with 

 nutritious and palatable sap, offer no mean inducement 

 to browsing animals in search of food. Many plants may 



