74 [CHINESE ECONOMIC TBEES 



This tree grows in mixed forests and sometimes attains a height of 

 100 feet. It is closely allied to the European tree hazel Corylus colurna, 

 of which it was once considered a variety. 



ALNUS 



Trees or shrubs. Leaves deciduous, alternate, stalked, serrate or 

 dentate, rarely entire, pinnately veined, stipules deciduous. Leaf buds 

 in winter usually stalked, club shaped, few scaled. Flowers monoecious 

 in cylindrical catkins, apetalous. Staminate catkins terminal or 

 subterminal, elongated, in clusters of 2-6, conspicuous in winter; flowers 

 small, 3 to each scale; stamens 4, filaments short, undivided; calyx 4 

 lobed. Pistillate catkins much smaller than and below the staminate, 

 naked in winter or concealed within lateral scaly buds, several together or 

 rarely solitary; flowers naked, 2 to each bract; ovary 2 celled, ovules 

 solitary in each cell; style 2. Fruit a strobile or woody cone with 

 persistent scales, remaining on the branches after the liberation of the 

 nutlets. Nutlets winged or wingless, 1-seeded by abortion. 



About 25 species in Europe, Asia and N. America. The genus is 



characterized by staminate catkins appearing before the leaves and by 



pistillate flowers developing into woody cones. Nearly all the species 



prefer moist situations and they are usually found alongside of ponds 



' and streams. The wood of some species is hard and durable in water. 



AInus cremastogyne Burkill. 



Tree 30 m. tall with rough, gray bark. Young branchlets glabrous. 

 Leaves obovate or ovate, acuminate, rounded or broadly cuneate at the 

 base, margin irregularly serrate, smooth, dark green above, paler and 

 with tufts of brown hairs on the veins below, 6-13 cm. long; petioles 6-13 

 mm. long. Catkins solitary, axillary, appearing in the spring. Cone 

 ovate, solitary, 2 cm. long; peduncles 4-5 cm. long. Nutlet provided with 

 a broad wing. 



Szechuan. 



This tree is suitable for planting in wet sites. The wood is used 

 chiefly for fuel and it is occasionally planted along the borders of rice 

 fields, apparently for this purpose. 



Alnus lanata Duthie may be a form of the above. 



The other Chinese species are shrubby. 



