(69) 香港杜鵑
Rhododendron hongkongensis Hutch.
杜鵑花科(Ericaceae)

英文名 (English name): Hong Kong Azalea

中國境內現狀：易危 (VU)
Status in China: Vulnerable (VU)

形態特徵：常綠灌木，高1-4米，多分枝；小枝灰色，頗光滑，嫩時密被腺毛。葉聚生於小枝上部，倒披針形，長4-5.5厘米，寬1.5-2厘米，頂端短尖，基部漸狹，邊緣稍外卷，下面稍帶白粉；葉柄長0.5-1厘米。花單生於葉腋；花冠近輻狀，長2-3厘米，5裂，白色或帶粉紅色，上部裂片內有紫藍色斑；雄蕊5；子房被具短柄的腺毛，卵圓形。蒴果卵圓形，長6-8毫米，多少被腺毛，有粗糙的小疣狀凸起；宿存花萼裂片常反卷和皺縮。

地理分布：聶高信山、馬鞍山、大嶼山。廣東。

生境與生態：生於山谷、水邊、疏林中。花期：4月；果期：10月。

本種於1847至1850年間在香港島首次發現。白色或帶粉紅色的花甚美麗，可供觀賞。因生長地點多在郊野公園內而受到保護。位於馬鞍山的分布點亦列為「具特殊科學價值地點」。本種受《林務規例》(香港法例第96章附例)保護。漁護署已進行遷地保護，城門標本林內有栽培。

Description: Evergreen shrubs, 1-4 m tall, many-branched; branchlets gray, smooth, densely covered with glandular hairs when young. Leaves crowded on upper part of branches, oblanceolate, 4-5.5 cm long, 1.5-2 cm wide, apex acute and mucronate, base attenuate, margin slightly revolute, obscurely glaucous beneath; petiole 0.5-1 cm long. Flowers solitary in axils of leaves; corolla nearly rotate, 2-3 cm long, white or pinkish, the upper lobes tinged with purplish blue blotches inside; stamens 5; ovary ovoid, covered with short stipitate glandular hairs. Capsule ovoid, 6-8 mm long, more or less glandular hairy, coarsely tuberculate; persistent calyx lobes often revolute and shrinking.

Distribution: Mount Nicholson, Ma On Shan, Lantau Island. Guangdong.

Habitat and ecology: In thin forests of ravines, by streams. Flowering: Apr.; fruiting: Oct.

The species was first collected and described from Hong Kong Island between 1847 and 1850. The beautiful white to pinkish flowers make it an attractive ornamental plant. In Hong Kong, most of the localities of its occurrence are in Country Parks under protection. The locality at Ma On Shan has been listed as a SSSI. The species has also been listed under the Forestry Regulations (Cap. 96 sub. leg.). Ex-situ conservation has also been conducted. Some living specimens are planted in the Shing Mun Arboretum.

參考文獻(References):
譚沛祥，1987：廣東植物誌1：315，圖339。廣東科技出版社，廣州。