PROTECTION OF POLLEN. 107 



sappears, and in Australia the numerous Mimosese and Myrtacese and the 

 [•oteacese, which constitute the principal part of the dense copses just referred 

 , are accordingly destitute of any contrivance capable of acting as a protection 



the pollen. These plants preserve their rigid character even during the 

 jwenng season; the filaments bearing the anthers project in large numbers far 

 iyond the small floral envelopes in the Acacias and in the innumerable species 

 ' Callistemon, Melaleuca, Eucalyptus, Galothamnus, and Metrosideros, and the 

 yliform prolongations of the ovaries in Proteacese, on the top of which the 

 )llen is deposited when set free from the anthers, spring up and stretch out 

 iprotected far beyond the restricted perianth. 



Flowers which inhabit a region where moisture is deposited from the atmo- 

 )here in greatest quantity in the flowering season exhibit an entirely different 

 irm. In the mountains of Central and Southern Europe, where this coincidence 

 !curs, the plants whilst in flower must be prepared for daily showers. In addition 

 rery plant drips with dew in the early morning, and drops of water are deposited 

 1 leaves and flowers in the course of the day by the mists as they roll by. 

 i must often happen that the pollen remains for days together hanging to 

 le opened anthers before it is carried away by bees or butterflies to the stigmas 

 [ other flowers. Here if anywhere is an instance of the necessity of ample 

 lelter for the pollen. Examine the plants composing the smaller brushwood 

 E such a region, and you will find how great a contrast they afford to the plants 

 f the thickets of Australia. The flowers of the Heather (Galluna vulgaris), 

 ad of the Bilberry, Bog Whortleberry, and Cowberry (Vaccinium, Myrtillus, 

 \ uliginosum, V. Vitis-Idcea) have bell- or cup-shaped corollas which hang down 

 •om curved stalks with the mouths of the flowers towards the earth, and so cover 

 le pollen-laden anthers. Similarly, we find the Alpine Rhododendrons ("Alpine 

 .OSes "), which clothe the mountain sides, with flowers inclined at a right angle 

 5 the erect stalks so that the anthers are perfectly sheltered beneath their tilted 

 ells. 



All the many contrivances whereby pollen is directly protected from wet are 

 E the same nature as the above, the method of protection being by some such 

 )ofing in or envelopment of the anthers. That these adaptations should exhibit 

 ) much variety in detail in spite of the uniformity of their object is due to the 

 mdition that the envelopment must itself not be carried too far. On no account 

 lUst the dissemination of the pollen or its transport by wind or insects to the 

 igmas of other flowers be hindered; nay, the very same parts of a flower which 

 lelter the pollen from rain frequently have the additional function of assisting 

 le dispersion of the pollen when the rain is over. 



In the enumeration of arrangements for warding off injury to pollen from 

 etting, the various coverings and protections are described as equally effective 

 ir rain as for dew. But this, of course, is not for the same reason. A roof 

 rotects structures from! rain by intercepting the drops, and from being bedewed 

 nee it diminishes radiation from the bodies beneath and thus keeps them at a 



