White and Greenish 



fertilization, some of the bladder-campion flowers have stamens 

 only, some have a pistil only, some have both organs maturing 

 at different times. In all the night-flowering Silene, each flower, 

 unless unusually disturbed, lasts three days and three nights. 

 Late in the afternoon of the first day, when the petals begin to ex- 

 pand, the five stamens opposite the sepals lengthen in about two 

 hours, and by sunset the anthers, which have matured at the same 

 time, are covered with pollen. So they remain until the forenoon 

 of thesecond day, and then the emptied anthers hang like shrivelled 

 bags, or drop off altogether. Late in the second afternoon, the 

 second set of stamens repeat the actions of their predecessors, bend 

 backward and shed their anthers the following, that is to say the 

 third, morning. But on the third afternoon up rise the S-shaped, 

 twisted stigmas, which until now had been hidden in the centre 

 of the flower. Moths, therefore, must transfer pollen from younger 

 to older blossoms. 



"With this lengthening and bending of the stamens and stig- 

 mas," says Dr. Kerner, "goes hand in hand the opening and 

 shutting of the corolla. With the approach of dusk, the bifid 

 limbs of the petals spread out in a flat surface and fall back against 

 the calyx. In this position they remain through the night, and 

 not till the following morning do they begin (more quickly in 

 sunshine and with a mild temperature, more slowly with a cloudy 

 sky and in cold, wet weather) to curl themselves up in an in- 

 curved spire, while at the same time they form longitudinal 

 creases, and look as though they were gathered in, or wrinkled ; 

 . . . but no sooner does evening return than the wrinkles dis- 

 appear, the petals become smooth, uncurl themselves, and fall 

 back upon the calyx, and the corolla is again expanded." 



Curiously enough, these flowers, which by day we should 

 certainly say were not fragrant, give forth a strong perfume at 

 evening the better to guide moths to their feast. From eight in 

 the evening until three in the morning the fragrance is especially 

 strong. The white blossoms, so conspicuous at night, have little 

 attraction for color-loving butterflies and bees by day ; then, as 

 there is no pollen to be carried from the shrivelled anther sacs, no 

 visitor is welcome, and the petals close to protect the nectar for 

 the flower's true benefactors. Indeed, few flowers show more 

 thorough adaptation to the night-flying moths than these Silene. 



Common Chickweed 



(Alsine media] Pink family 

 (Stellaria media of Gray) 



Flowers Small, white, on slender pedicels from leaf axils, also in 

 terminal clusters. Calyx (usually) of 5 sepals, much longer 



172 



