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遵照毛主席关于“一切实际工作者必须向下作调查”和“有了优良品种,即不增加劳动力、肥料,也可获得较多的收成”的教导,我们在1975—1976年对全省重点地区进行杨树调查,发现由国外引进的一种速生杨树良种——欧美杨。欧美杨为雌株,叶二角形,长约9厘米,宽9.1厘米,叶缘呈波状锯齿,叶柄扁平,平均长度7.2厘米;芽小,黄褐色,有粘液。欧美杨是欧洲黑杨与美洲黑杨的杂交后代,与常见的加杨同属黑杨派欧美杨系。在形态上,它与加杨容易区别:加杨干直,树皮粗糙,纵深裂(少数光皮加杨例外),叶子稠密,暗绿色,侧枝分枝角度小,窄冠,塔形;欧美杨干形略弯曲,基部1~3米树皮纵浅裂,灰褐色,树干中上部较光滑,侧枝分枝角度较大,树冠卵圆形,叶子稀,浅绿色。
According to Chairman Mao’s teaching on “All actual workers must investigate downwards” and “There are excellent varieties, that is, we can get more crops without increasing labor force and fertilizers”, we focused on the province from 1975 to 1976 Poplar survey conducted in the region found that introduced by foreign countries a poplar poplar - Europe and the United States Yang. Europe and the United States Yang female plant, leaf-shaped, about 9 cm long, 9.1 cm wide, leaf edge was wavy serrated, flat petiole, the average length of 7.2 cm; bud small, brown, mucus. Europe and the United States poplar Populus is the hybrid between Populus nigra and Populus nigra, with the common plus Populus Populus black Europe and the United States Department of Yang. Morphology, it is easy to distinguish between Yang and Yang: Yang dry straight, bark rough, deep cleft (exception a few light Pigeon exception), dense leaves, dark green, small branches angle, narrow crown, tower; Slightly curved, the base of 1 to 3 meters bark longitudinal cracking, taupe, the trunk of the upper part of the more smooth, large branch angle, crown oval, thin leaves, light green.