IO4 



FLOWERS OF THE CORNFIELDS 



honey glands are situated, and two in the place of the functionless 

 stamens that do not produce pollen. 



The glands can be seen when the calyx expands, and are visible 

 and accessible from outside. Insects can reach them without touching 

 any of the other parts of the flower. The insect thrusts its proboscis 

 down between the stamens, because the flowers are so close. The 



stamens laterlengthen 



"^N&t and are twisted out- 



wards, and the oppor- 

 tunities for cross-pol- 

 lination agree with 

 the conditions in 

 Cardamine pratensis. 

 When the flowers 

 wither and the stigma 

 lengthens the anthers 

 turn the pollen- 

 covered sides up- 

 wards, bend down- 

 wards, and self-pol- 

 linate the plant. The 

 visitors are Diptera 

 (Syrphidse), Hymen- 

 optera (Tenthredin- 

 idse, Apidae), Coleop- 

 tera (Coccinellidse), 

 and Lepidoptera 



(Eiiclidia glyphica, 

 Burnet Nochia). 



The seeds of 

 Charlock are dis- 

 persed by the plant 



itself. The pods open and allow the seeds to be scattered around 

 the parent plant. 



It is a sand plant, and requires a sand soil, which may be derived 

 from any of the older formations, such as Coal-measures, Keuper, Lias, 

 &c., in which there are sandstones. 



This plant is infested by Ceuthorhynchus sulcicollis, Psylliodes 

 chrysocephalus, Meligethes ceneus, Balanienus brassier (Beetles), Athalia 

 spinarum (Hymenoptera), Large White (Pieris brassier], Small White 

 (P. rapce], Green-veined White (P. napi), Turnip Moth (Agrotis 



CHARLOCK (Brassica arvensis^ O. Kuntze) 



