(First upload on April 3 2014. Last on March 17 2022) [ 日本語 | English ]

Cycas revoluta Thunb.

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

[Engler's syllabus (エングラー体系)]

Cycadaceae Pers.

Identification by vegetative organs is difficult
Microscopic structures of organs are about the same with those of Ginkyo
The development of secondary xylem is not well
One genus
Cycas L.
C. circinalis L. (インドソテツ)
C. revoluta Thunb. (ソテツ)
C. rumphii Miq. (ナンヨウソテツ)
C. taitungensis C. F. Shen, K. D. Hill, C. H. Tsou et C. J. Chen (タイワンソテツ)

Zamiaceae (classified into Cycadaceae by Engler)

Cycas revoluta in Japan


Sotetsu (ソテツ, 蘇鉄), King sago palm
Life form: evergreen shrub
Distribution: China - southern Japan (southern Kyushu and Nansei Islands*)

* southwestern islands in the Ryuku archipelago

Habitat: rocky sites near seacoasts
Physiology: nitrogen-fixing
Utilization: ebible seeds (after removing the poison)

Fig. Cycas and its allies. inside of seed: cotyledone that has already formed, enclosed by endosperm (内胚乳). endosperm = haploid. Cross section: p = pith, v = vascular bundle, lt = leaf trace

[1/2] The sperms were discovered from this king sago palm by Dr. Ikeno (池野成一郎) in Meiji 29 (1896) as the first record from the world. The plant grew in front of the Archaeology Resource Center of Kagoshima Prefecture Museum on March 20 2015. [3] at Atomic Bomb Dome (原爆ドーム) in Hiroshima, western Japan, on March 14 2014. [4] in the Osaka Castle Park (大阪城公園) on February 5 2022.