THE ANGIOSPERMAE 



1337 



refer particularly to one species S. aizoides, which he considers illustrates 

 this type of flower very well. 



Saxifraga aizoides occurs in the mountainous parts fo this country 

 (Fig. 1247). It is a small rosette plant which bears loose panicles of yellow 

 flowers, spotted with dull red. There is a five-parted calyx and five petals 

 which open out quite flat to expose the ten stamens. The ovary is pro- 

 longed into a divergent pair of styles with small apical stigmas. The lower 



Fig. 1247.- — Saxifraga aizoides. A, Flowering shoot. B, Young flower in section 

 with connivent stamens discharging pollen. C, Later stage after anthers are 

 shed. Ovary and stigmas fully developed. 



part of the ovary is spotted in a way similar to the petals. Nectar is secreted 

 around the base of the ovan,' and is almost completely exposed. The flowers 

 are protandrous; the outer stamens ripen first and there is a progressive 

 ripening of one stamen after another till all ten stamens have discharged 

 their pollen. Only after this do the stigmas mature. Cross-pollination is 

 therefore almost inevitable, though in some districts the style appears to be 

 receptive before pollen shedding is complete. Though sometimes visited 

 by bees and small butterflies, the species is mainly pollinated by small flies, 

 similar to the house fly, and also by ants and small beetles. 



Though this example may be cited as representative of temperate plants, 

 by far the most striking examples are seen in the tropics. The most remark- 



