2S2 ARUM. 



40 " C and its warmth can be felt if \-on touch it. 

 The spadix decreases much in weight during tliis rise 

 of temperature, for it consumes a portion of its substance 

 b\' increased respiration. In fact we miglit almost sa\' 

 that the spadix was feverisli ! ft is \er\' interesting that 

 tliis phenomenon should be made use of b^• tlie plant as 

 a device for cross-fertilisation. 



No botanist will fail to notice the yellow spots on 

 nian\' of the lea\'es of An'sanan I'lilg-arc in tlie spring. 

 The\- are caused h\ a curious para.site which attacks 

 and kills portions of the Arisarum leaves. In highly 

 organised plants these blights are generalh^ caused hv 

 colourless Hyplioiiiyccies. But in this case it is caused 

 \>\ a green alga (one of the Siphoheae), Pliyllosiplioii 

 Arisari. This is remarkable because living parasitic 

 plants are not as a rule green. Since the green colouring 

 matter is characteristic of plants \\-hich obtain their own 

 nourishment from the air, it is natiualh- not needed as 

 soon as parasitism begins. ^Fhe green colouring matter 

 may perhaps be retained in Phyliosiphon because this 

 alga has not long been living in this manner. All its 

 closest relations support themselves independenth- and are 

 mostly aquatic. 



CHAPTER IV. 



It is ver\- lovely in the little garden of the Hotel 

 d'ltalie at Garavan when the full moon stands high in 

 the heavens. Then it hangs over theosea, tracing silvery 

 hieroglyphics on its shimmering surface. Its beams shine 

 into the garden through the trembling foliage of the 



