PERFECT FLOWERS 49 



and the bees of the genus Halictus to good 

 effect, as we shall discover later in the sea- 

 son by the great numbers of seed-vessels which 

 ripen. 



WAKE-ROBIN; BIRTHROOT Trillium erectum 

 April- June 



The common name for this plant is not strictly 

 exact, for the robins come first to awake the Tril- 

 lium; yet the flower appears among the advance- 

 guard to assure us that spring has come. Even 

 the dull, brownish purple-red is welcome at this 

 season; but I cannot say as much for its disagree- 

 able, fetid odour. Yet both colour and odour please 

 the green flesh-flies (Lucilia carniciana), who are 

 the best pollen porters for the Trillium. (See the 

 sketch on page 5.) 



In flowers like this, the insects make a dash for 

 the centre and, if they hit the mark, land upon 

 the stigma. Leaving what pollen they bring, 

 they then climb down upon the corolla, and, ob- 

 taining nectar and more pollen, fly away without 

 again touching the stigma. They may, however, 

 miss the centre of the flower altogether, and rest 

 upon the petals only, thus doing neither good nor 

 harm. 



