v.] REMARKABLE LEAVES. 89 



flower, or to the same flower a second time, and is 

 pushed by its comrades into the bucket, and then 

 crawls out by the passage, the pollen mass neces- 

 sarily comes first into contact with the viscid stigma, 

 and adheres to it, and the flower is fertilised. Now 

 at last we see the full use of every part of the flower, 

 of the water-secreting horns, of the bucket half full 

 of water, which prevents the bees from flying away, 

 and forces them to crawl out through the spout, and 

 rub against the properly-placed viscid pollen masses 

 and the viscid stigma." Origin of Species. 



One small group of orchids (Caleana), confined to 

 New Holland, possess an irritable lip, which, in fine 

 weather, bends back, and leaves the column un- 

 covered and open to the insects ; but if it rains the 

 drops cause the irritable lip to close up over the 

 column, which is thus effectually secured from rain. 

 Similar phenomena occur in Drakcea and Spiculcza, 

 other species of orchids. 



We must now take leave of this interesting group 

 of plants, and again pay some slight attention to 

 peculiar leaves. One of the most remarkable of 

 these is the Lattice-leaf (Ouvirandra fenestralis), a 

 native of Madagascar. It is an aquatic plant, pos- 

 sessing tuberculate roots and submerged leaves. For 

 our acquaintance with it we are indebted to the well- 

 known missionary, the Rev. W. Ellis. The remark- 

 able portion of the plant is the leaf, which at first 

 si;ht looks like a mere skeleton-leaf one that has 



o 



had all the cellular tissue cleaned off the fibres with 

 open spaces between the nerves or fibres. But the 

 microscope shows us that the fibres are really en- 



