Vasilis Teodoridis:
Salicaceae | Populus
7. Populus rotundifolia Griffith; Not. Pl. Asiat. 4: 382. 1854.
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Trees to 20 m tall; bark grayish white; smooth. Old branches gray; branchlets dull brown; at first pilose; glabrescent. Buds reddish brown; ovoid or conical; scales white downy; viscid. Leaves of short branchlets with petiole compressed; 3.5-6.5 cm; leaf blade ovate-orbicular or deltoid-orbicular; 5.5-8.5 x 5-8 cm; larger on sprouts; abaxially grayish green; adaxially green; both surfaces white downy when leaves unfold; base shallowly to deeply cordate or truncate; margin sinuously obtusely serrate; apex shortly acuminate or obtuse. Leaves of sprouts with petiole shorter; leaf blade ovate-orbicular; larger; base cuneate or subcordate. Female catkin 4-7 cm; ca. 10 cm in fruit; rachis pilose. Female flower: ovary long ovoid; glabrous; style short or subsessile; stigma 2-parted. Capsule long ovoid; 2-valved.
Mountain slopes; circa 2800 m. Gansu; Guizhou; Shaanxi; Sichuan; Xizang; Yunnan [Bhutan].
7a. Populus rotundifolia var. duclouxiana (Dode) Gombocz; Math. Termesz. Kozl. 30: 130. 1908.
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Populus duclouxiana Dode; Bull. Soc. Nat. Hist. Autun. 18: 190. 1905.
Female flower: style short or subsessile; stigma 2-parted; each part diverging.
* Mountain slopes; circa 2800 m. Gansu; Guizhou; Shaanxi; Sichuan; Xizang; Yunnan
This variety differs from var. rotundifolia (which occurs in Bhutan) as follows: leaves deltoid-orbicular; larger; apex shortly acuminate or obtuse; female catkin usually more than 10 cm.