Sago Palm Ferns

from Wikipedia, the free encyclopedia
Sago Palm Ferns
Cycas rumphii with a cone-shaped male inflorescence

Cycas rumphii with a cone-shaped male inflorescence

Department : Vascular plants (tracheophyta)
Subdivision : Seed plants (Spermatophytina)
Class : Cycadopsida
Order : Cycads (Cycadales)
Family : Cycadaceae
Genre : Sago Palm Ferns
Scientific name of the  family
Scientific name of the  genus

The sago palm ferns ( Cycas ), also called Cycas cycads , are the only genus of the plant family of the Cycadaceae within the division of the cycads (Cycadophyta). The 90 to 108 species have their areas in tropical to subtropical areas of the Old World and on Pacific islands including Australia. In East Asia, the so-called false sago is obtained from the trunks of two species, Cycas revoluta and Cycas circinalis , while the real sago mainly comes from the - unrelated - sago palm .


Illustration by Cycas micholitzii

Vegetative characteristics

Cycas species are long-lived, perennial plants . Most of the time the trunks are unbranched. The species are very different in size. The largest species are Cycas angulata , which can reach heights of up to 12 meters and trunk diameters of up to 40 centimeters, and Cycas thouarsii , which reach heights of up to 10 meters in trunk diameters of up to 45 centimeters.

When the leaves are thrown off, the leaf scars remain on the trunk as clear marks. Young parts of the plants are hairy.

The feathery leaf fronds that look very similar to fern fronds are typical. Unlike palm fronds, the fronds of the cycads are fork-veined ( dichotomous ). Initially, the fronds, similar to ferns, are rolled up. Lower leaves are also formed, alternating with the leaf fronds. On the trunk, the leaves are formed helically. Usually a wreath of new leaves forms at the same time, usually once a year, the older the plant, the more new leaves per year. The leaflets have a main nerve and never a lateral nerve.

Generative characteristics

Cycas species are dioecious separately sexed ( dioecious ). In all species of the Cycadaceae family (= genus Cycas ), only the male plant specimens have cone-shaped inflorescences ( sporophylls ) (in contrast to the other Cycadophyta). The female plant specimens have reshaped ( fertile ) leaves, which are formed in a wreath at the top of the plant alternating with the leaves - on the edges of these fertile leaves (sporophylls) there are individual ovules. After fertilization, the seeds then form on the edge of these fertile leaves. The similarity of the female fertile leaves to the way in which ferns have arranged their spore systems is remarkable .


In the roots of Cycas species, nitrogen-fixing cyanobacteria of the order Nostocales live as endosymbionts . It is the only known symbiosis of this kind in gymnosperms. The plant produces a special type of root, the "coralloid" roots, especially to absorb blue-green algae. It is absorbed by infection from the outside, from the ground. The genus Nostoc is usually mentioned as the symbiote, but in fact other species are probably involved.


The habitats of the Cycas species vary greatly: They thrive from the coast and coastal plains to mountain regions. Many species grow in forests, a few in savannahs and many on rocky slopes and places with little vegetation. Some species live in areas with frequent forest fires . Some species in arid areas are seasonally green, that is, they are without leaves in the dry season . Some species with a major distribution along the coast have seeds that can float on the water, such species often have a large area.

Male plant of Cycas circinalis with young and old cones
Male cone of Cycas revoluta
Female fertile leaves of Cycas revoluta with seeds
Female plant of Cycas rumphii with fertile leaves and seeds
Habit of Cycas thouarsii with trunk and leaves
Seed of Cycas thouarsii

Distribution and systematics

Cycas TYPES have their areas in tropical and subtropical areas of the Old World and the Pacific islands including Australia. Important home areas are Southeast Asia , southern China , Malaysia , tropical areas of Australia , Oceania , Japan , Africa and Madagascar .

In the genus of the sago palm ferns ( Cycas L. ) there are 90 to 108 species:


Individual evidence

  1. ^ Wolfgang Franke : Nutzpflanzenkunde. Usable crops of temperate latitudes, subtropics and tropics. 4th, revised and expanded edition. Thieme, Stuttgart a. a. 1989, ISBN 3-13-530404-3 , p. 81.
  2. José-Luís Costa, Per Paulsrud, Peter Lindblad: Cyanobiont diversity within coralloid roots of selected cycad species. In: FEMS Microbiology Ecology. Volume 28, No. 1, ISSN  0168-6496 , 1999, pp. 85-91, doi : 10.1111 / j.1574-6941.1999.tb00563.x (open access).
  3. a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj bk bl bm bn bo bp bq br bs bt bu bv bw bx by bz ca cb cc cd ce cf cg ch ci cj ck cl cm cn co cp cq cr cs ct cu cv cw cx cy cz da db dc dd de df dg dh di dj dk dl dm Rafaël Govaerts (Ed.): Cycas. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved May 5, 2019.
  4. ^ A b Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold : The great pikeperch. Encyclopedia of Plant Names. Volume 2: Types and Varieties. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5406-7 .

Web links

Commons : Sago Palm Ferns ( Cycas )  - Collection of images, videos and audio files