i8o 



MONOCOTYLEDONS 



Fig. 227. — A sta- 

 men of Arujn 

 maculatum. 



p e 1 1 a r y flower of 

 Arum inaculatuni. 



carpellary flowers are a number of sterile carpellary 

 flowers Xsf) without ovules. The staminate flower consists 

 of a small group of three or four stamens (or at the very 

 base of the staminate region each flower may have only 

 one or two stamens). The anthers are 

 sessile (fig. 227). Above the staminate qv 

 flowers the band of hairy structures repre- '' 

 sents a belt of sterile flowers 

 {sf). Fruit. — After pollina- 

 tion each ovary gives rise to 

 a single red berry (fig. 229). 

 Thus the carpellary inflor- 

 escence produces a cluster 

 of berries (fig. 230), which 

 is an infructescence, because 

 it is formed by several flowers, 

 and not by one. Pollination. 

 — In spite of their incon- 

 spicuousness, the flowers are insect-pollinated \ the inflor- 

 escence emits a peculiar odour, and the purple tip of the 

 spadix aids in alluring the small flies which 

 effect cross-pollination. The whole inflor- 

 escence forms a trap to catch these minute 

 flies, which creep down the spathe into the 

 chamber formed by the tube of the latter. 

 The ovaries mature before the stamens, and 

 at this stage of 

 flowering the pali- 

 sade of hairs span- 

 ning the mouth of 

 the spathe - tube 

 does not prevent 

 the entrance of the 

 midges, though it 

 hinders their de- 

 parture. If the 

 flies have come 

 from another 

 spathe, they bear 

 pollen and pollin- 

 ate the stigmas of the ovaries which are now ready. 



Fig. 23g, 



■A berry of Arum 

 maculaium cut open. 



Fig, 230.— Infruct- 

 escence of Arum 

 ntaculatum. 



After 



