252 THE FERTILISATION OF FLOWERS. [PART III. 
bright yellow flowers, and dense tufted habit. The flowers secrete 
honey from five yellowish scales at the base of the flower, lying 
between the anthers and carpels. The honey is accessible to — 
insects with very short tongues, and the flowers are visited by 
numerous species of different orders. Cross-fertilisation for the 
most part takes place. For when the flowers open, and their — 
petals spread fully out into a five-rayed star, the five stamens 
which alternate with the petals and which stand erect round the 
middle of the flower now dehisce ; while the five others which are — 
inclined outwards with the petals remain closed: the stigmas are 
still quite immature. As the first five stamens wither, the others © 
rise up towards the centre and open; very soon, even before this © 
Fic. 88.—Sedum acre, li. 
i 1.—Flower, in first stage. 8, sepals; p, petals; a*, outer anthers, alternating with the petals a 
a’, inner anthers, opposite the petals; n, nectaries; ov, ovaries. 
2.—Apex of a style, in first stage. . 
8.—Ditto, in second stage, after all the anthers have dehisced. 
second ring of stamens withers, the stigmas ripen. By sufficient _ 
insect-visits, which in sunny weather never fail, the pollen is 
wholly, or in great part, removed before the stigmas are capable 
of being fertilised. If, however, in dull, windy weather, insect-_ 
visits are lacking, the anthers remain stored with pollen until the 
full ripening of the stigmas, and self-fertilisation becomes possible. 
Since the flowers are small compared with the insects, the latter 
of the flower or creep inwards from the edge. ‘ 
Visitors: A, Hymenoptera—(a) Apidae : (1) Bombus Rajellus, K. $ ; (2) 
Cilissa tricincta, K. 9; (8) Andrena cingulata, K. 9 ; (4) A. parvula, K. 2 ¢, 
