Česká geologická služba
Virtual museum
Home  > Taxonomy > Plants > Gymnosperms > Cycases

Cycadopsida (Cycases)

      Cycads /ˈsaɪkædz/ are seed plants typically characterized by a stout and woody (ligneous) trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female (dioecious). Cycads vary in size from having a trunk that is only a few centimeters tall to trunks up to several meters tall. They typically grow very slowly and live very long, with some specimens known to be as much as 1,000 years old. Because of their superficial resemblance, they are sometimes confused with and mistaken for palms or ferns, but are only distantly related to either. Cycads are found across much of the subtropical and tropical parts of the world. They are found in South and Central America (where the greatest diversity occurs), Mexico, the Antilles, southeastern United States, Australia, Melanesia, Micronesia, Japan, China, Southeast Asia, India, Sri Lanka, Madagascar, and southern and tropical Africa, where at least 65 species occur. Some can survive in harsh semidesert climates (xerophytic), others in wet rain forest conditions, and some in both.[citation needed] Some can grow in sand or even on rock, some in oxygen-poor swampy bog-like soils rich in organic material, and some in both.[citation needed] Some are able to grow in full sun, some in full shade, and some in both.[citation needed] Some are salt tolerant (halophytes). Cycads belong to the biological division Cycadophyta. There are three extant families of cycads, Cycadaceae, Stangeriaceae, and Zamiaceae. Though they are a minor component of the plant kingdom today, during the Jurassic period they were extremely common. They have changed little since the Jurassic, compared to some major evolutionary changes in other plant divisions.

Source: http://en.wikipedia.org/wiki/Cycad


 

YA1275
Alethopteris bohemica YA1275
ZS_16
Alethopteris refracta ZŠ16
ZS_17
Alethopteris refracta ZŠ17
ZS_10
Alethopteris urophylla Brongniart ZŠ10
ZS_11
Alethopteris urophylla Brongniart ZŠ11
ZS_12
Alethopteris urophylla Brongniart ZŠ12
ZS_26
Alethopteris valida ZŠ26
ZS_23
Alethopteris valida ZŠ23
ZS_25
Alethopteris valida ZŠ25
ZS_22
Alethopteris valida ZŠ22
ZS_19
Alethopteris valida ZŠ19
ZS_24
Alethopteris valida ZŠ24
YA1278
Alethopteris zeilleri YA1278
YA1279
Alethopteris zeilleri YA1279
WA64
Trigonocarpus WA64

In the Virtual Museum there are total 42 samples

Virtual museum of the Czech Geological Survey, www.geology.cz, (C) Czech Geological Survey, 2011, v.0.99 [13.12.2011]