38 



duces a decided odor, but there is no visible nectarA 



T he odors of fiowers have been divided into five groups: 

 undolo^ aminoid, paiaffinoid, benzonoid, terpenoid. The 

 indctoi'd odors are frequent in aroids, stapelias, aristolochias 

 and some orchids. These carrion like odors are attractive to 

 insects the feed on carrion, like some flies and beetles. The 

 flowers have vivid spots and reddish brown veins. The ami- 

 noid group is cJesely related to the atove, and is derived 

 from the amido derivatives in which one, two or three parts 

 of the water in the ammonia is replaced by the radical alco- 

 hol. 



In hawthorn {Crataegus^ the odor is due to trimethyla- 

 mine It is similar in the flowers of pear (Pyru8 communis.) 

 Somewhat different is the odor in manna ash {FraxintiS 

 omus,) horse chestnut [Aesculus Hippocostanum), tree of 

 heaven [Ailanthus). 



The benzoloid odors occur in various species of Dian- 

 thus, the odor of Asperula odorata, lily of the valley 

 {Gonvallaria majdlis), Heliotropium, Reseda odorata, 

 etc. From this class one might distiaguish special odors as 

 in heliotrope, violet, vanilla, etc. ('it is also noteworthy that 

 these same odors occur in plants distantly related^ Carna- 

 tion odors occur in some orchids as Platanthera, also in 

 Orohanche, Missouri current {itihes atMreMm,) narcissus {N. 

 poeticus ) The paraflSne odors occur in Valeriana offici- 

 nalis Ruta graveolens, grape ( Vitis vinifera) honey 

 locust (Gleditschia triacanthos.) The odor from newly 

 filled honey combs is allied to some of the odors that belong 

 to this group, as buckwheat, white and other clovers. 



The last group comprises the aetherial oils but more pro- 

 perly terpene, these occur at times in certain glandular hairs 

 or other parts of the plant, seldom in parts of the flower, 



