94 FLOWERS OF LAKES, RIVERS, ETC. 



style. After the lower papillae emerge from the cylinder and the root 

 of the corolla they spread so far apart that an insect must touch them 

 in visiting the flower. If sufficient insects have visited them to clear 

 the pollen away before the stigmas are exposed or receptive, the plant 

 is cross-pollinated, but if pollen is left when the stigmas are exposed an 

 insect may self-pollinate it. Even if no insects visit it cross-pollina- 



HABIT AND HABITAT FLOWERHEAD (Nat. Size) ? 



HEMP AGRIMONY (Eupatorium cannabinum, L.) 



tion may follow, styles and stamens of neighbouring florets coming in 

 contact. It is visited by Apis, Bombus, Eristalis, Eckinomyia, Dexia, 

 Lucilia, Pieris rapa, Thecla querczis, Lycana, sp. ; Peacock ( Vanessa 

 Io\ Silver-washed Fritillary (Argynnis p a phia\ Marbled White 

 (Melanargia galatea\ Speckled Wood (Pararge egeria\ Hesperia, sp.; 

 and a Neuropterous insect, Panorpa. 



The achenes are provided with a pappus, and the fruit is angled 

 and adapted for wind dispersal. 



Hemp Agrimony is a semi-aquatic plant, which is partly a humus- 

 or peat-loving plant, and requires humus, and partly a clay-loving 



