SPONTANEOUS MOVEMENTS IN PLANTS. 
841 
the gardens and the goat's-beard open at sunrise and always 
close by about noon, the evening primrose opens only in the 
evening, and many others last for but a single day. So re¬ 
gular is the time of opening and closing of some flowers, 
that Linnaeus drew up a list, which he termed a “ floral 
clock.” The singular part of the affair is, that with many 
flowers the time of opening and closing is determined, not by 
the degree of light, or by the temperature or humidity of the 
atmosphere, but absolutely by the hour of the day. The 
giant w 7 ater-lily of the Amazons, the Victoria regia , opens, for 
the first time, about 6 p.m., and closes in a few hours, then 
opens again at 6 a.m. the next day, remaining open until 
the afternoon, when it closes and sinks below the water. 
Other plants, again, open their flowers only in the bright 
sunshine, as the beautiful yellow centaury or Chlora gper- 
foliata , the sundew, Drosera rotundifolia , &c. In the latter 
plant, belonging to the same natural order as the Venus's 
Fly-trap, and possessing a slight irritability of the leaves, 
Mr. Worthington Smith has noticed also a strong sensi¬ 
tiveness in the petals, the flowers closing suddenly when 
touched. 
Irritability or sensitiveness, similar to that of the leaves of 
the Sensitive Plant, is not uncommon in the flower. An in¬ 
stance has been alluded to in the petals of the sundew; it 
occurs also in the lip of the corolla of several of the orchis 
tribe. It is, however, more common in the proper organs of 
reproduction, as the style of S'tylidium, the stamens of the 
berberry, &c., and is then directly connected with the process 
of fertilisation of the ovule. In Stylidium , an Australian 
genus, the style and filaments are adherent into a column, 
which hangs over on one side of the flow er. When touched, 
it rises up and springs over to the opposite side, at the same 
time opening its anthers and scattering the pollen. The 
stamens of the various species of Berberis and Mahonia, to 
the former of which our common berberry belongs, exhibit 
this irritability to a remarkable degree. If touched with a 
pin or other object at the base of the inside face of the fila¬ 
ment, the stamen will spring violently forward from its place 
within the petal, so as to bring the anther into contact with 
the stigma, and after a time slowly resume its original po¬ 
sition. At first sight it may seem as if this contrivance w 7 ere 
intended to ensure the fertilisation of the pistil from the 
pollen of its own flower. In reality, however, the reverse is 
the case; the excitation takes place in nature when an insect 
entering the flower for the sake of the honey in the glands 
at the base of the pistil, touches the inside of one of the 
