REPRODUCTION BY SEED 167 



flowers are small and inconspicuous, but the stigmas are 

 large and feathery, and project beyond the flower. The 

 anthers burst when the air is dry, and clouds of golden 

 dust are shot from them. If they burst in wet weather, 

 rain would wash the pollen upon the earth, and it would 

 be wasted. In many wind-poUinated flowers the pistils 

 ripen flrst, so that they may be ready to catch the first 

 pollen that is wafted along their way. Among wind- 

 poUinated plants are many of our lofty forest-trees — 

 pines, oaks, beeches, poplars, elms, birches — ^bushes like 

 the hazel, climbers like the hop, water-plants like Myrio- 

 phyllum, weeds like stinging-nettles and plantains, and 

 all the grasses, reeds, and sedges. Most of our catkinate 

 trees (p. 180) are wind-poUinated, and they flower very 

 early when the trees are bare of leaves. The presence of 

 the leaves would obstruct the passage of the pollen to 

 the flowers. The oak flowers after the leaves are out, but 

 the position and form of the leaves are such that they 

 interfere very little with the passage of the pollen through 

 the tree. If foliage is present, the wind-pollinated flowers 

 are raised well above the leaves — e.g., grasses. In the 

 pine the poUen is provided with floats. 



There is little doubt that in the evolution of flowers 

 wind-pollinated flowers preceded insect-poUinated flowers, 

 the advance being made in the direction of economy of 

 material and of increasing certainty of pollination. But 

 of existing flowers, some that are wind-poUinated have 

 always been so — e.g., conifers ; others have degenerated 

 from insect-pollinated ancestors. The latter usually 

 show signs of their degradation. The pollen may be still 

 somewhat sticky — e.g., Poterium Sanguisorba ; remnants 

 of attractive corollas may persist — e.g., Thalictrum minus ; 

 and honey may even be secreted — e.g., Rumex, Poterium. 



3. Insects. — ^Flowers pollinated by insects are called 

 " entomophilous " (Gr. etdomon, insect). Unlike the 

 wind, the movements of insects are directed by a definite 

 purpose. They visit flowers, sometimes for shelter, 

 occasionally as a suitable place to deposit their eggs, 

 but generally in quest of food. The adaptations of 

 flowers to insects and of insects to the flowers which they 

 visit are very curious and wonderful. Beauty of form, 

 colour, scent, and honey are all adaptations which have 

 arisen among flowers for the attraction of insect- visitors. 



