The Cycasare all palmy evergreen woody plants. The caudex is in the shape of cylinder, surrounded by theindeciduouspetiole base. It bears pinniform leaves that are spirally arranged, 0.5 to 2.4 meters long, with thick and hard keratinose. The pinna is strip-shaped, 18 centimeters long, with visible counter curls in the edges. It bears acrogenous flowers that are dioecious, with long cylindric male cones and oblate female cones. The florescence lasts from June to August. The flat ovoid seeds are mostly red, about 2 to 4 centimeters long.
Cycasis a kind of heliophyte, preferring growing in warm, dry and well-ventilated places. It grows slowly, and is not cold-resistant. It grows better in fertile subacid sandy soil. The seeds ripen in October.
Family Cycad is the most original family among the existing seed plants; therefore it is treated as one of the key protection objections in all countries. In China there is only 1 genusof Cycad in existence, consisting of 8 species, such as TaiwanCycas, Yunnan Cycas (Siam Cycas), Hainan Cycas, Sichuan Cycas, Rumphius Cycas, Nepal Cycas, Micholitz Cycas (Dragon Cycas) and Tukou Cycas.They are distributed in the southeast, south and southwest of China. Most Cycas plants have high ornamental value because of their graceful and peculiar appearances, and enjoy a long cultivation history in China.
Chaye Cycas
Chaye Cycasis a kind of evergreen palmy plant, with the Latin name ofCyeas micholitzii Dyer.It can attain the height of 4 meters. The leaves, 2 to 3 meters long, are spirally arrayed and pinnately divided, with short thorns on both sides of the petiole. The seedlings are covered by whitening, and turn dark green while growing. The seeds turn yellow when they ripen, about 2.5 centimeters long.
It is distributed inLongzhou, Daxinand Chongzuo of Guangxi Zhuang Autonomous Region, and some limestone terrains in Mile of Yunnan Province. It is a kind of calcicolous plant, and usually grows in lower part of tors among low limestone peak clusters. Such kind of growing habit is rarely found in plants of theCycadFamily. It is useful for scientific research to protect species and study the classification of Cycad.The frond of the plant is emerald green all the year round and can be used for landscaping and ornamental purposes.
Panzhihua Cycas
Its Latin name isCycas panzhihuaensis.Bearing fleshy root with substantive coralloid fungus roots but no axial root, it usually grows on rocks and in swallets, and has the characteristics of resisting drought, fire and infertility. In its habitat, they blossom and fructify almost every year. The florescence begins in March and the seed ripen in September. Generally speaking, the florescent male and female plants do not bear new leaves any more in the same year.
It is distributed in the south of Sichuan Province and north of Yunnan Province. This archaic surviving species is only found in China. The discovery ofPanzhihua Cycashas expanded the north distributive limit of Cycas to north latitude of 27"11", which is of great significance for the study of plantage, plant geography, paleoclimate, paleo-geography and glacier.
Bichi Cycas
Its Latin name isCycas pectinata.It can attain the height of 3 meters. The leaves, about 1 to 1.5 meters long, are pinnate and totally divided. The petiole is 15 to 30 centimeters long, with two-millimeter-long sparse thorns on both sides. It has 80 to 120 pairs of pinnas, with hard keratin. It bears oval globular seeds of 4.5 to 5 centimeters long that turn rufous when ripened.
In China it is distributed in monsoon broad-leaved evergreen forests in south subtropical plateau of Yunnan Province. It blossoms once every 1 to 3 year. The florescence lasts from June to July and the seeds ripen in February and March of the ensuing year. Its megasporophyll is in the similar shape of the Permian cycad fossil, which is of great value for the study on evolution and distribution of cycad, paleogeography and paleoclimate.
Taiwan Cycas
Its Latin name isCycas taiwaniana. It has a cylindric caudex with a diameter of 20 to 35 centimeters. The leaves, about 180 centimeters long, are pinnate and totally divided. It has 90 to 140 pairs of pinnas, which are linear, keratinous, and bright dark green.
Taiwan Cycas is only found in China, discontinuously distributed in Taiwan and Hainan provinces. It usually grows in sunny ravines, rock cliffs or woodland of river banks, with the characteristics of resisting fire, preferring warmth, and fearing cold, humidity and shade. Being graceful in appearance, it is a fine ornamental plant.
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