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Cycas hainanensis

时间:2022-01-12 16:33:11

Cycas hainanensis (Cycas, Cycadaceae), is a wild plant native to Hainan and its type specimen was found in Wanning City, Hainan.

Protection class

Cycas hainanensis is a Class I national protected wild plant. It is also listed as Endangered (EN) on the IUCN Red List of Threatened Species and listed on CITES Appendix II.

Distribution and habitat

Cycas hainanensis is distributed in Sanya, Changjiang, Baisha, Wuzhishan, Ledong, Baoting, Qiongzhong, Wanning, Lingshui, Wenchang, Qionghai, Haikou, and other places in Hainan. Not many plants of the species are scattered at the open forest 100-1000 meters above sea level.

Morphological characteristics

Cycas hainanensis is considered as a shrub species or a tall herbaceous plant. Its pinnate leaves are about 1m long, and the petiole is about 20 cm long. The cross-section of the leaf is quadrilateral round, densely covered with thorns (3-4 mm) on both sides, with each thorn about 1 cm apart. The nearly opposite pinnate lobes are long and leathery, stretching obliquely upward. The central pinnate lobes are about 15 cm long and 6 mm wide. The rachis is in the angle of about 60 degrees, which is usually straight or slightly curved. The front end is tapering while the base is asymmetrically contracted. The lower side extends downwards and the margins are slightly back-scrolling. On the upper surface there is dark green luster, with central veins clearly uplifting, whereas the underside is light green with central veins slightly rugose. Both sides are smooth. The young megasporophyll is covered with brown pubescence which would gradually disappear. The upper top is obliquely ovoid, about 7 cm long and 5 cm wide, with 5-7 feathery, diamond-shaped edges that are 2-3 cm long and 2.5 mm thick. A sharp-pointed tip is found with oblong, flat lobes, and the upper part is hard, about 3.5-4 cm long and 1.5-2 cm wide. The edge in lower middle part is very smooth. There are several serrations or splits on the upper part, where a long thorn (1-1.4 cm) grows at the tip. There are a few less noticeable jagged edges; the lower petiole of megasporophyll is about 7 cm long, and the cross-section is quadrilateral round, with two oval, glabrous ovules arranged on both sides. Immature seeds are reddish brown when pressed and dried. They are wide and obovate, slightly flattened with irregular folds on the surface.

Growth habits

Cycads like light, warm, dry and well ventilated climate. They grow well in fertile sandy soil. This slow-growing plant has a lifespan of about 200 years. In the southern tropical and subtropical areas in South China, cycads over 10 years old blossom and bear fruit almost every year, while those cultivated in the Yangtze River Basin and North China almost grow without flowers or fruit.

雨林动态

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