148 



MONOCOTYLEDONS 



The spadix of Colocasia appears at the end of the rainy season. 

 It differs from that of Caladium in having the spike prolonged 

 beyond the stamens into an acute, yellowish club whieh bears no 

 Howers, and serves as a means of attractlnr/ 

 insects on which the plant depends for the 

 fertilization of its ovules (tigs. 131, 132). 



Besides this appendage and the large, 

 yellow spathe surrounding it, insects are 

 also enticed by: 



(a) a strong smell of the spadix, which is dis- 

 agreeable to us, but does not seem to be so 

 to the midges that visit the flowers; 



QS) the nectar, secreted by the stigmas 

 of the pistils, and the co])ioiiS pollen of the 

 stamens, constituting food for them, and 



(c) the high teniperatiire in the globular 

 enlargement of the spathe at its lower 

 part, causing them to seek refuge there. 



3. After flowering, the spathe fades 



and nothing remains of the whole spadix, 



except the lower part, where the pistils ripen 



into a cluster of Berries Avhich are eaten 



and dispersed by birds. 



Fig. 131.— 4. After this the whole plant withers 



Spathe and ^^^^ perishos, excepting the Tubers, in 



Colocasia ^^'^^ich plenty of food is stored up for the 



aniiquornm next season. When the rains begin again, 



{,\ of natural ^j^ggg plants are among the first to cover 



the ground with their fresh green. — It 



is also through these tubers that the plant is i)ropagated. Like 



the Potato, it throws out long underground slioots, the runners or 



stolons, portions of them being hlled with starch and swelled up 



to form fresh tubers, which eventually grow into sei)arate plants. 



Fis;. 132.- 



Spatlie reinov- 



0(1 bhowing' 



spadix with 



pistillate and 



staniinato 



flowoi's. 



Othei' Aroideit;. 



Another wcU-knowii species of this order is Alocasia nnicro- 

 rhiza {Kan. Marasanige), the .i;i:^^aiitic tubers of wliich ni-e 



