DICOTYLEDONES : POLTPETAL^ : DISCIFLOR^. 



615 



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

 articulated to the winged petiole (Fig. 82 G) ; the leaf is sometimes spinous. 



Citrus medica is the Citron ; C. niedica var. Limonum, is the Lemon ; C. 

 medica var. Liinetta, is the Lime; Citrus Aurantium war.Bigaradia (or Cvuliftiris) 

 is the Bit eror Seville Orange, and C. Aurantium sinense is the Sweet Orange ; 

 Citrus nnbilis is the Mandarin Orange ; and Citrus decunuma is the Shaddock : 

 all orig nally derived from tropical Asia. 



Fig. 416.— Flower and floral diagram of Citrus. A Open flower ; c. corolla ; s the partially 

 connate stamens ; n the stigma. B Bud ; k calyx ; c corolla ; d oil-glands. 



Order 9. Meliace^. Disc various: stamens 5-10, generally 

 monadelphons ; 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. Simarubace^. Disc conspicuous: flowers aotino- 

 morphic, sometimes diclinous : stamens usually 10, and then 

 sometimes {e.g. Ailanthus) distinctly obdiplostemonous : gynasceum 

 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. 



Ailanthm 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. Burseracr^. Disc usually annular : flowers actino- 

 morphic : gynfficeum syncarpous ; ovary with two ovules in each 

 loculus : there are resin-passages in the bast. 



BoswelUa 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 andrcecium, actino- 

 morphic or zygomorphic, sometimes monosporangiate : gynsBceum 

 oligomerous, usually syncarpous. Mostly trees. 



