(20) 白桂木
Artocarpus hypargyreus Hance ex Benth.
桑科 (Moraceae)

英文名 (English name): Silver-back Artocarpus, Sweet Artocarpus.

中國境內現狀：易危 (NT)。已載入《中國植物紅皮書》和《 廣東省珍稀瀕危植物圖譜》。
Status in China: Near Threatened (NT). Recorded in China Plant Red Data Book and Illustration of Rare & endangered plant in Guangdong Province.

形態特徵：常綠喬木，有乳汁；嫩枝及葉柄被鏽色短柔毛。葉互生，革質，橢圓形或倒卵狀長圓形，長7-15厘米，寬5-8厘米，全緣，背面密被灰色短絨毛。雌雄同株：雄花序倒卵形或棒狀，長1.5-2厘米；雌花序圓頭狀。聚合果球形，直徑約1.5厘米，橙黃色，外被褐色短柔毛，表面有乳頭狀突起。

地理分布：香港各地。海南，廣東，廣西，福建，江西，湖南，雲南有分布。

生境與生態：生於丘陵和低山常綠闊葉林以及風水林中。花期：春末夏初。
　　

樹形美麗，葉深綠，有光澤，也是良好的園林綠化樹種。本種多生於低海拔至中海拔地區，由於各地的市區發展和建設，數量已日漸減少。在香港，本種較常見，且很多生長地點在郊野公園內，也未受任何特別威脅。已進行人工繁殖及栽培。

Description: Evergreen tree with milky juice; young shoots and petioles covered with rusty short hairs. Leaves alternate, leathery, elliptic or obovate-oblong, 7-15 cm long and 5-8 cm wide, entire, densely grayish tomentellate. Plant monoecious: staminate flowers on obovoid or club-shaped stiff spikes, 1.5-2 cm long; pistilate flowers in a dense globose head. Fruit a syncarp, ca. 1.5 cm in diam., orange, papillate and brown pubescent.

Distribution: Various places in Hong Kong. Hainan, Guangdong, Guangxi, Yunnan, Hunnan, Jiangxi, Fujian.

Habitat and Ecology: In lowland broadleaved evergreen forest and fung shui wood. Flowering: late spring to early summer.
　　

The beautiful shape of the tree and its dark green leaves make it very suitable for cultivation as an ornamental species. The species occurs on lowlands, and is susceptible to habitat destruction. In Hong Kong, this species is relatively common and many localities of wild occurrence are in Country Parks under protection. The species has also been artificially propagated.

參考文獻 (References):
陳偉球，1987：廣東植物誌 1：185，圖201。廣東科技出版社，廣州。
傅立國，1992: 中國植物紅皮書 1：464-465。科學出版社，北京。
吳德鄰等，1988：廣東珍稀瀕危植物圖譜13，圖39。中國環境科學出版社, 北京。
黎存志等，1999：香港珍稀瀕危植物的分布及保育，熱帶亞熱帶植物學報7（1）：1-6。