193 



pointed. President Carnol, corolla double. President Poincare, 

 corolla triple. Montaigne, hose-in-hose, or corolla tube double. 

 Victor Lemoiiie, flower globular. Charles Sargent, petals large, 

 twisted. 



LinneI 



President CaR-not President Poincare 



MONTAIQNE. ViCTOR-LemoinE ChARlLE5 SaRQENT 



Fig. 2. Flower forms of lilac varieties (natural size). 



The Odor of Lilacs 



The odor of plants is due to essentia! oils, which are waste prod- 

 ucts of their life-processes. The combination of these oils in 

 flowers is called attar, a word familiar to all in "attar of roses," the 

 oil distilled from the petals of roses, chiefly the Damask rose. 

 Attar is more complex, chemically, than the essential oils in odor- 

 ous leaves, and this explains why the odor of flowers is more deli- 



