190 CHINESE ECONOMIC TREES 



Hupeh and Szechuan, and Kiangsu. 



A very valuable timber tree usually of medium size. The wood is 

 white or yellowish, close grained and very heavy. It is used for making 

 wheelbarrows, axles, pulley blocks, tool handles and oil presses, and 

 may well be adapted to street paving. 



RUTACEAE 



Trees or shrubs or herbs usually containing aromatic essential oil. 

 Leaves alternate, rarely opposite, simple or compound, usually with 

 pellucid, oily glands. Flowers perfect, regular, cymose or paniculate; 

 sepals 4-5, often connate, imbricated; petals 4-5, usually free; stamens 

 4-5 or 8-10, rarely 15 or more, inserted at the base of the disk, filaments 

 usually distinct; ovary superior, 2-5 lobed, 2-5 celled on a stalk with a 

 glandular disk at the base; ovules 1 to many in each cell; style more or 

 less connate. Fruit a fleshy drupe or berry, or a capsule or separating 

 into several drupelets, rarely winged. 



About 100 genera and 900 species, mostly tropical. The volatile 

 fragrant oils, characteristic of this family, are much used in perfumery and 

 inedicine. A very important family horticulturally and commercially, 



KEY TO GENERA 



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I. Fruit a berry with leathery rind and cells distended with juicy 

 pulp; orange-like. 



A. Leaves simple, persistent Citrus. 



B. Leaves trifoliate, deciduous Poncirn*. 



II. Fruit not orange-like, but drupaceous or capsular. 



A. Fruit capsular. 



1. Leaves alternate; plants often armed. .. .Zanthoxyhim. 



2. Leaves opposite; plants unarmed Evodia. 



B. Fruit drupaceous; winter buds inclosed by the base of the 

 petiole; leaves odd-pinnate Phdlodendron . 



PHELLODENDRON 



Deciduous trees, sometimes with thick, corky hark. Winter buds 

 naked, enclosed by the base of the petiole. Leaves opposite, odd pinnate, 



