REPEODUCTION BY SEED 



175 



—a 



they act as fly-traps, holding their pollinators captive 

 until their duty is accomplished. The most familiar fly- 

 trap in England is the cuckoo-pint {Arum maculatum), 

 found under shady hedges everywhere. The inflorescence 

 is a long spike (spadix) of small unisexual flowers (Fig. 73), 

 partially enclosed in a great sheathing bract, the spathe. 

 The female flowers are borne lowermost upon the spadix, 

 and consist of a large number of 

 pistils without any perianth. A 

 short distance above these are 

 the male flowers — a multitude 

 of almost sessile stamens. Then 

 comes, at the constriction of the 

 spathe, a brush of downward- 

 turned hairs, which partially close 

 in the chamber below. The 

 spadix ends above in a long, 

 dark-coloured, club-shaped organ, 

 whose dark purple colour and 

 disagreeable smell are so attrac- 

 tive to flies. Flies, attracted by 

 the showy spadix, enter the 

 inflorescence, push their way 

 through the neck of the spathe, 

 and enter the chamber where the 

 flowers are. Once in, they cannot 

 get out, for the forest of pendent 

 hairs bars the exit. But the 

 quarters are comfortable, and 

 there is plenty of food. The 

 pistils ripen flrst, and are pol- 

 linated by the flies when they 

 first enter the chamber. Each 

 stigma, when ripe, secretes a drop 

 of honey, and the flies, in their 

 movements to get at it, dust 

 any pollen they may have on their bodies upon the 

 receptive stigmas. After a while the stamens mature, 

 and, bursting, powder the insects with pollen. At the 

 same time, the flower begins to fade, the hairs dry up, 

 and the spathe droops and falls over, leaving an open 

 passage for the insects. They fly out, but, having become 

 accustomed to the darkness of the trap, they make for 



Fio. 73. — Intloeescbncb 

 OF Cuckoo-Pint {Arum 

 maculatum). (Reduced.) 



a, spathe ; b, fleshy axis of 

 spadix ; c, hairs at con- 

 striction of spathe ; 



d, staminate flowers; 



e, sterile pistillate flowers ; 

 /, fertile pistillate flowers. 



