白背柳檢視原始碼討論檢視歷史
白背柳 |
中文名:白背柳 學 名:Salix balfouriana 界:植物界 門:被子植物門Angiospermae 綱:雙子葉植物綱Dicotyledoneae 目:楊柳目 Salicales 科:楊柳科Salicaceae 屬:柳屬Salix 種:白背柳 |
白背柳(bái bèi liǔ,學名:Salix balfouriana),為雙子葉植物綱、楊柳科、柳屬的植物,為中國的特有植物。分布於中國大陸的雲南等地,生長於海拔2,800米至4,000米的地區,常生長在山坡及灌叢中,目前尚未由人工引種栽培。 [1]
白背柳形態特徵
白河柳 灌木或小喬木,高可達5米。當年生枝被絨毛;二年生枝無毛或稍有毛,紅黑色。芽黑褐色,有毛。
葉橢圓形、橢圓狀長圓形或倒卵狀長圓形,長6-8(12)厘米,寬2-4厘米,先端鈍或急尖,扭轉,基部圓形或寬楔形,上面無毛或沿脈上有短柔毛,深綠色,下面密被絨毛,幼葉常雜生鏽色絹毛,成熟葉的毛逐漸脫落,下面白色,上年的落葉上面呈灰褐色,全緣,萌枝葉長可達18厘米,邊緣有腺齒,開花時葉很小。
花序先葉開花或與葉同時開放,長2-(4)厘米,粗6-10毫米,花序梗短或無,基部無葉或有1-2小葉;雄蕊2,花葯黃色,稀紅色,花絲2/3有柔毛;苞片倒卵狀長圓形,先端圓截形或有缺刻,外面上部紅黃色,被柔毛,上部和邊緣的毛較長,內面無毛或稍有毛;
腺體2,背生和腹生,有時分裂;子房卵狀圓錐形,無柄,有的呈紅紫色,密被柔毛,花柱長,2深裂,柱頭2裂;苞片同雄花;腺體1,腹生。
果序長可達8厘米,其梗也伸長;蒴果長5.5毫米,近無毛。花期4月下旬-5月上旬,果期6-7月。 [2]
Salix balfouriana Schneid. in Bot. Gaz. 64: 137. f. B. 1-4. 1917; Hand.-Mazz. Symb. Sin. 7: 74. 1929; Hao in Fedde, Rep. Beih. 93: 96. t. 37: 74. 1936.——S. forrestii Hao, 1. c. 69. t. 19: 38. 1936, syn. nov.
Shrubs or trees to 5 m tall. Two-year-old branchlets glabrous or slightly pilose; juvenile branchlets reddish black, tomentose. Buds blackish brown, pilose. Leaves very small at anthesis; petiole 1-1.5 cm, pilose; leaf blade elliptic, elliptic-oblong, or obovate-oblong, 6-8(-12) × 2-4 cm, to 18 cm on shoots, glandular dentate, abaxially tomentose, usually rust-colored sericeous when young, when mature glabrescent, whitish, adaxially glabrous or pubescent along veins, dark green, base rounded or broadly cuneate, margin entire or inconspicuously glandular dentate, apex obtuse or acute, contorted; fallen leaves of previous year grayish brown. Flowering precocious or coetaneous. Catkins 2(-4) cm × 6-10 mm; peduncle short to nearly absent, with 1 or 2 leaflets at base or not; bracts obovate-oblong, abaxially reddish yellow distally, downy, ciliate, adaxially glabrous or slightly pilose, apex rounded-truncate or notched. Male flower: adaxial and abaxial glands sometimes divided; stamens 2, free; filaments pilose nearly throughout; anthers yellow, rarely red. Fruiting catkin to 8 cm, with elongated peduncle. Female flower: gland adaxial; ovary reddish purple, ovoid-conical, pubescent, sessile; style long, 2-lobed; stigma 2-cleft. Capsule to 5.5 mm, subglabrous. Fl. Apr-May, fr. Jun-Jul.
- Mountain slopes, thickets; 2800-4000 m. Sichuan, NW Yunnan
白背柳近種區別
本種與白背柳S. balfouriana Schheid.,銀背柳S. ernesti Schneid.相似。主要區別為本種葉下面密被伏生的鉛灰色絹毛,有光澤,至老葉毛也很少脫落,葉脈不明顯,花柱及柱頭不扭曲。
白背柳生長環境
生長於海拔2800-4000米的山坡或灌叢中。