DICOTYLEDONES : POLTPETALJE : DISCIFLOR^S. 



615 



the leaf, which is typically pinnate, is reduced to its terminal leaflet which is 

 articulated to the winged petiole (Fig. 32 G) ; the leaf is sometimes spinous. 



Citrus medico, is the Citron ; G. medico, var. Limonum, is the Lemon ; C. 

 me.dica var. Limetta, is the Lime; Citrus Aurantium var. Bigaradia (or C.vulyari*) 

 is the Bitter or Seville Orange, and C. Aurantium sinense is the Sweet Orange ; 

 Citrus nolrilis is the Mandarin Orange ; and Citrus decumana is the Shaddock : 

 all orig nally derived from tropical Asia. 



B 



FIG. 416. Flower and floral diagram of Citrus. A Open flower ; o corolla; s the partially 

 connate stamens ; n the stigma. B Bud ; Tc calyx ; o corolla ; d oil-glands. 



Order 9. MELIACE,E. Disc various : stamens 5-10, generally 

 monadelphous ; the filaments have stipulate appendages ; carpels 

 usually 5 ; no oil-glands, but simple sacs (p. 139). 



Mahogany is the wood of Swietenia Mahagoni (America). The wood of species 

 of Cedrela is often erroneously termed " cedar-wood " : Guarea, Carapa, Melia, 

 are other well-known genera. 



Order 10. SIMARUBACEJ;. Disc conspicuous : flowers actino- 

 morphic, sometimes diclinous : stamens usually 10, and then 

 sometimes (e.g. Ailanthus) distinctly obdiplostemonous : gyiiaeceum 

 sometimes apocarpous : ovule usually solitary in each loculus : 

 there are no oil-glands in the leaves, but the cortex and wood 

 contain a bitter substance. 



Ailanthus glandulosa, the Tree of Heaven, from China, is a tree with multi- 

 jugate pinnate leaves and a winged indehiscent fruit ; it is often cultivated. 



Order 11. BURSERACEJD. Disc usually annular : flowers actino- 

 morphic : gynseceum syncarpous ; ovary with two ovules in each 

 loculus : there are resin-passages in the bast. 



Boswelli'i serrata (East Africa) yields Olibanum, a gum-resin; Commiphora 

 Schimperi and abyssinica yield the gum-resin Myirh (Arabia and Abyssinia). 



Cohort II. Sapindales. Flowers typically pentamerous and 

 obdiplostemonous but with reduction in the androecium, actino- 

 morphic or zygomorphic, sometimes monosporangiate : gynoDceum 

 oligomerous, usually syncarpous. Mostly trees. 



