THE YOUNG NATUKALIST. 



319 



White water-lily (Nymphea ) v 

 alba) ^ rj " " 



Nottingham catchfly (Sileite ) ng at yj 

 nutans) \ ^ 



VI. 

 VII. 



Night-flowering catch tiy ) 

 (Selene nocti flora) \ 



Evening primrose (Enothcra ) 



biennis) \ 



Some people will doubtless be surprised at 

 the short period of the day during which 

 certain flowers are expanded, the common 

 nipplewort being open only for four or five 

 hours in the early morning and remaining 

 closed during the rest of the day. Several 

 others, as the little round-leaved sundew, with 

 its delicate bell-shaped flowers of purest 

 white, are rarely seen with the petals un- 

 folded ; whilst others, like the daisy, " wee 

 modest crimson-tipped flower," awake with 

 the first beams of the morning sun, follow 

 him with faithfulness during his upward 

 course, exposing their blushing beauties to his 

 burning gaze, and only close when he with- 

 draws his rays and sinks to rest in the glowing 

 west. Many well-known and conspicuous 

 flowers, when once their blossoms have 

 become fully developed, open once for all 

 and remain expanded till their petals shrivel, 

 wither, or drop off. Such are the roses, 

 wallflowers, foxgloves, &c. Although there 

 seems to be no hour of the night or day in 

 w hich flowers may be found awaking or going 

 to sleep, yet by far the greatest number are 

 found to unfold in the morning hours from 

 3 to 7, and to close in the afternoon, from 4 

 to 8. The large family of composite plants, 

 which includes the dandelion, daisy, hawk 

 weeds, &c, exhibit the phenomena of sleep in 

 a marked degree, most of the flowers being 

 more or less thoroughly closed during dark- 

 ness. The influence of light, especially the 

 direct rays of the sun, has the most powerful 

 effect on the expansion of flowers, and they 

 may be stimulated into activity, and their 

 blossoms expanded, in other words awakened 

 early, by artificial light. This has been 

 recently demonstrated by experiments with 

 the electric light, and in the same way their 



sleep may be unnaturally prolonged by being 

 immured in darkness. Moisture and warmth, 

 as well as light, have a powerful influence on 

 the sleep of flowers. On cold, cloudy, damp 

 days, many flowers do not expand at all, thus 

 the scarlet pimpernel has come to be recog- 

 nised as a rural barometer, and is called the 

 poor man's weather glass, because if its bright 

 scarlet blossoms remain closed it is sure to 

 rain, whereas if they are fully expanded in the 

 morning it is certain to be a fine day. 

 Another explanation of the periodical expan- 

 sion of flowers is furnished by the results of 

 recent researches into the relationships of 

 flowers and insects. This is peculiarly 

 applicable to the night-blooming plants, 

 whose flowers expand in the evening when 

 the influence of light is withdrawn. A 

 familiar illustration is the common white 

 campion (Lychnis vespertina), the large, showy, 

 snow-white flowers, of which are conspicuous 

 in dry sandy fields and hedgerows. A closely 

 allied plant, the night-flowering catchfly, has 

 its petals curiously curled up during the day, 

 and they are unrolled at night. Night- 

 blooming plants are so constructed as to be 

 most easily fertilised by the visits of night- 

 flying moths, and to aid in attracting their 

 visits such flowers are usually very fragrant, 

 and as gaudy colours would be of no use in 

 the dim twilight, they are generally pure 

 white, which makes them more conspicuous 

 in the subdued light. For the same reason 

 flowers which are open during a limited por- 

 tion of the day are fully expanded at the time 

 when the particular insects by whose visits 

 they would be most benefitted are on the 

 wing. Anyone who wishes to watch the 

 opening and closing of flowers will find an 

 interesting study by gathering a handful of 

 tke yellow goatsbeard, which is common 

 during this month on rubbish heaps and rail- 

 way embankments, put them in a glass of 

 water, when the blassoms will expand with 

 wonderful regularity for a week together. 

 If these are unobtainable, any of the yellow- 

 composite flowers will illustrate it fairly well. 



