52 CHINESE ECONOMIC TEEES 



POPULUS 



Deciduous trees with buds covered by several imbricated bud scales. 

 Leaves alternate, pinnately veined, entire, crenate, dentate or serrate, 

 stalked. Flowers dioecious, precocious (appearing before the leaves in 

 the spring), in stalked, pendulous catkins. Staminate flowers in 

 elongated catkins composed of numerous flowers each subtended by a 

 deciduous, toothed, cut or cleft bract. Stamens 4-12 or 20-60 attached 

 by a short filament to the cup-like disk which replaces the perianth; 

 anthers 2 celled, red or purple. Pistillate catkins not so compact; ovary 

 sessile on the oblique, cup-like disk, 1-celled; style short, stigma 2-4. 

 Mature fruiting catkin often moniliform or necklace-like. Fruit a capsule 

 dehiscent into 2-4 recurved valves. Seeds very small, surrounded by 

 tufts of silky hair which gives the mass a cottony appearance. 



Quick-growing, intolerant trees, comprising about 50 species, widely 

 distributed throughout Europe, America, Asia and Africa. Poplars 

 thrive on any soil but they prefer alluvial land bordering ponds and 

 streams. They are rapid growing trees, sometimes attaining great size, 

 and are especially suited for windbreaks and hedges. Several species 

 produce timber used in woodworking industries and for paper pulp. The 

 tannin from the bark is used in Europe for curing hides; the leaves are 

 fed to cattle for fodder. Some uses to which poplar wood is put are for 

 flooring, packing cases, wooden shoes, bowls and dishes and matches. 

 Waste land in China might be profitably planted to the poplars. Exotic 

 species recommended for experimentation are: — 



P. tremula, P. tremuloides, P. nigra, P. deltoidea, P. alba. Propagation 

 by seeds is most uncertain, cuttings afford the practical means of increase. 

 Both the poplars and willows .nre subject to numerous insect and 

 fungous attacks. 



Populus simonii Carrieie 



A medium sized to tall tree of elegant habit and rapid growth. 

 Young shoots slender, sometimes pendulous, reddish-brown, deeply 

 angled and 5 ridged, conspicuously white lenticeled. Leaves small, 5-13 

 cm. long, diamond shaped or ovate, tapering at both ends, finely toothed, 

 dark green above, pale green below, glabrous on both sides. Petioles 

 short, channeled above, red on young trees. Staminate catkins about 

 3 cm. long. 



