THE DICOTYLEDOXES 



1665 



example, Ononis spinosa (Rest Harrow), Lotus corniculatus (Bird's-foot 

 Trefoil), Anthyllis vulneraria (Lady's Fingers), Astragalus glycyphyllos 

 (Milk Vetch), Hippocrepis comosa (Horseshoe Vetch), Lathyrus pratensis 

 (Meadow Vetchling), and Melilotus arvensis (Melilot). 



To the number of ornamental plants cultivated in gardens and green- 

 houses the Papilionaceae contribute very considerably. Some have been 

 mentioned above, among the others we may cite especially Galega, Baptisia, 

 Erinacea, Sophora, CoroniUa and Colutea. 



Mention may also be made of two genera from which important 

 insecticides have been marketed recently. The first is the genus Derris. 

 D. elliptica and D. trifoUata are climbing plants living in the jungle under- 

 growth of India and Malaya. From the roots, which are referred to as Tuba 

 Roots, is obtained the derris powder of commerce. The second genus is 

 Lonchocarpus. From the species L. nicou which is locally common in South 

 America has been prepared a similar insecticide. In this case however the 

 material is made from the bark. The poisonous properties of both have 

 been known locally for a long time, for the natives use them to poison arrow 

 heads. The insecticidal property in both is due to an active ingredient 

 known as rotenone. 



The members of the Papilionaceae may be trees, shrubs or herbs, with 

 either simple or compound leaves, the latter not infrequently having one or 

 more leaflets modified as tendrils. Stipules are usually present and may 

 be either large and leaf-like, as in Pisum and Lathyrus, contributing largely 

 to the assimilating area, or small and reduced, or even modified into spines, 

 as in Robinia. 



The inflorescence is always racemose. It is commonly a simple raceme, 

 sometimes a panicle or a spike consisting of but few flowers. 



Fig. 1526. — Floral dia- 

 gram of Vicia faba 

 (Papilionaceae). 



The flowers (Fig. 1526) are hermaphrodite, hypogynous or perigynous 

 and zygomorphic, and are often of considerable size and brightly coloured. 



