PROTECTION OF POLLEN. 119 



If the filaments supporting the anthers charged with pollen are small and 

 lort, the perianth, which in the inverted flower constitutes their protective cover, 



also of small size, as may be seen, for instance, in the case of the Lily of the 

 alley {Gonvallaria majalis, cf. fig. 220'). A much longer envelope is assigned, 

 1 the other hand, to stamens with long filiform filaments. Flowers of the 

 ind possessing large petals but seldom need to be completely pendulous in 

 •der to shelter their pollen, it is usually sufficient for them to nod, i.e. to droop 

 little to one sida Thus, for example, the stalks of LiUum candidum bend in 

 le flowering season only just enough to incline the mouths of the flowers in a 

 teral direction. Usually the form of the protective cover is such that the rain 

 \,n trickle ofl" it in drops. A contrivance far less common is for the petals 

 )vering the anthers to form a receptacle out of which the water is periodically 

 nptied. An instance of this is afibrded by the South African Sparmannia 

 ^jparmannia Afncana). The flower-buds are grouped together in umbels, and 

 :e borne on stalks, which are curved in a semicircle outwards and downwards 

 w&j from the main axis, so that the flowers are inverted and their anthers 

 re turned towards the ground and covered over by the petals. When the flower 



open, however, the petals are not simply spread out like an umbrella, but are 

 ightly tilted back, i.e. upwards. The margins of the petals overlap one another, 

 id their outer surfaces, which, in consequence of the inverted position of the 

 ower are uppermost, thus form a basin open to the sky. When it rains this 

 isin placed above the anthers fills with water, thus adding to the weight borne 

 y the stalk, and as drop after drop increases the strain upon the latter a point 



at length reached when the basin tips over, letting the water flow over its 

 Ige without wetting the cluster of stamens suspended beneath it. This 

 lechanism preserves the pollen clinging to the dehiscent anthers of Sparmannia 

 rom rain and dew in spite of their apparent exposure, which to a hasty observer 

 )ems to render it inevitable that the stamens should be wetted. 



In some plants whose flowers are arranged in racemes a process of inflection 

 ikes place before the flowers open, which does not afiect the pedicels themselves 

 lit the axis from which they spring, the result being that the entire racemes or 

 )ikes become pendent. All the flowers are then inverted, and the petals act as a 

 )of in sheltering the pollen adhering to the anthers. This is the case in the Cherry 

 aurel (Prunus Laurocerasus), the Bird Cherry (Prunus Padus), the Barberry 

 3erberis), and Mahonia. In the Walnut, the Birch, the Hazel, the Alder, and the 

 oplar (Juglans, Betula, Gorylus, Alnus, Populus) also, the rachis of the spike 

 langes its position shortly before the dehiscence of the anthers thus providing 



shelter for the pollen as it becomes free. The male flowers of these plants 

 hilst in the bud condition are crowded closely together, and form a stiflf erect 

 dindrical spike. But before the flowers open the rachis of the spike grows in 

 ngth slightly and becomes pendent, whilst the flowers it bears are consequently 

 parated a little from one another and become inverted, so that the floral 

 ivelopes, which are composed of little scales and perianth-leaves, are uppermost 



