62 



short and mid-styled stamens; a third has a medium style 

 with short and long stamens. In order to have full and 

 complete fertility pollen must be brought from the long sta- 

 mens over to the long-styled, short stamens over to the 

 short-styled, and mid-stamens over to the mid styled form. 

 The honey in this plant is accessible to a large class of 

 visitors. 



Evening Primrose is a common weed. It is 

 Ouagraceae. , , , , , , t . , 



adapted to nocturnal Leptdoptera; but also to 



long-tongued bees. The flowers are bright yellow, open 



partially during the day but produces the greatest amount 



of odor during the evening. Trelease has observed that the 



Oenothera sinuata, L- is visited by the humming bird. 



Some species of Oenothera produce cleistogamus flowers. 



Fire Weed- JSpilobium angustifolium, L. is wide- 

 ly distributed in the northern hemispiiere. The flowers are 

 strongly proterandrous. The large and showy flowers are 

 arranged in a spike, the widely spreading petals on short 

 claws. The style is bent downwards. Herman Mueller 

 says of it: "The expanded lower ends of the filaments 

 form a hollow cone which encloses the base of the style and 

 the surrounding honey; where the style issues at the apex of 

 this cone, hairs upon the style prevent the entrance of rain- 

 drops, while insects easily gain access between the fila- 

 ments. " 



In young flowers the stamens, covered above with pol- 

 len, project forward as an alighting place for insects, while 

 the style is still shorter and bent forwards with its stigmas 

 folded together; in older flowers, the empty stamens are 

 forwards, and the style, greatly increased in length, pro- 

 jects forwards with its four stigmas outspread and recurved. 



