Cephalotaxus hainanensis
Cephalotaxus hainanensis is a species in the family of the head Yews ( Cephalotaxaceae ). It is native to southern China. The most similar to Cephalotaxus mannii and is therefore often viewed as a synonym of this species.
Description
Cephalotaxus hainanensis grows as a evergreen tree that can reach heights of growth of up to 20 meters and diameter at breast height of 0.5 to 1.1 meters. The light brown to reddish brown Stammborke flakes. The 8 to 10 inches long and 4.5 to 5.5 centimeters thick branches are elliptically shaped in cross-section to oblong - elliptical.
The relatively thin or leathery, straight or slightly sickle-shaped needles are linear shaped with a length of 5 to 7.5 centimeters and a width of about 3 millimeters to linear-lanceolate. You are at a 0-1 mm long stalk and go at an angle of 70 to 80 ° from the branches off. The symmetrical base of the needles is blunt to blunt - wedge- shaped, while the tip is mucronate. The needle edges are bent back. The Needles are dark green or olive-green and glossy on the needle base you will find 19 to 26 white to bluish white Stomatareihen.
The heyday of Cephalotaxus hainanensis extends from November to March, and the seeds ripen from August to October. The pale-yellow, male cones are spherical shaped with a diameter of 4 to 4.5 millimeters and are occasionally on a 1 to 5 millimeters long stem. They are in groups of six to eight and each contain seven to 13 Mikrosporophylle, each with three to four pollen sacs. The single constant, female cones have a 0.6 to 1 inch long stem. You are from a 2.2 to 3 centimeters long and 1.1 to 1.2 centimeters thick seed coat ( aril ) surrounding it. This is initially green and turns to maturity towards red. The inverted - ovate to ovate - elliptic wrong - seeds are 2.2 to 2.8 inches long and have a sharply pointed tip or stachelspitzige.
The chromosome number is 2n = 24
Distribution and location
The natural range of Cephalotaxus hainanensis comprises five deposits on the Chinese province of Hainan belonging to the main island of Hainan. Further populations there could be in the Chinese provinces of Guangdong and Guangxi.
Cephalotaxus hainanensis thrives at altitudes from 0 to over 1700 meters. The species is found in the mountains, where it grows in mixed forests and subtropical rainforests. Stocks on the Chinese mainland could form mixed stands with Cephalotaxus mannii.
Cephalotaxus hainanensis is classified as " critically endangered " in the IUCN Red List. The main risk the destruction of forests is called for the utilization for tourism. In the past, collecting bark and leaves mainly played wood felling and more recently for the extraction of cephalotaxine and harringtonine for the production of cancer drugs play an important role. The decline in the total population of the species is estimated to be approximately 126,000 trees and covers an area of less than 100 square kilometers on the island of Hainan. The Chinese government has to protect the kind imposed a Fällverbot.
Use
Especially before the wood of the species was used. From the leaves and bark of the cephalotaxine alkaloids and harringtonine can be obtained, which can be used for the manufacture of anticancer drugs.
System
The first description was in 1953 by as Cephalotaxus hainanensis Hui Lin Li in Lloydia, Volume 16 ( 3), page 164 The species is treated by some authors because of the small morphological differences as a synonym of Cephalotaxus mannii.
Swell
- Christopher J. Earle: Cephalotaxus hainanensis. In: The Gymnosperm Database. www.conifers.org, November 23, 2012, accessed December 8, 2013 ( English).
- Liguo Fu, Nan Li, Thomas S. Elias & Robert R. Mill: Pinaceae. Picea. In: Wu Zhengyi, Peter H. Raven & Hong Deyuan (eds.): Flora of China. Cycadaceae through Fagaceae. Volume 4, Science Press and Missouri Botanical Garden Press, Beijing and St. Louis in 1999, ISBN 0-915279-70-3, Cephalotaxus hainanensis, p 87 ( this printed work is the same text online, Cephalotaxus mannii - Online).