Cycas revoluta

Cycas revoluta (Sotetsu [Japanese ソテツ], sago cycad, sago palm, king sago, Japanese sago palm) is a species of gymnosperm (a group of woody seed-producing plants) in the family Cycadaceae, native to southern Japan including the Ryukyu Islands. It is one of several species used for making sago, as well as a decorative plant. The sago cycad can be told apart by a thick coat of fibers on its trunk. The sago cycad is sometimes wrongly thought to be a palm, although the only similarity between the two is that they look similar and both make seeds.

Names
Cycads are not related to palms (Arecaceae), apparently similar only in how the leaves are arranged and that both are vascular plants and seed plants. The Latin name revoluta means "curled back", due to the curled leaves. This is also called kungi (comb) palm in Urdu speaking areas.

 Description 
This very evenly-shaped plant has a set of shiny, dark green leaves arranged in a circle. They come out of a thick hairy trunk that is normally about  in diameter, sometimes wider. The trunk is very low or below the ground in young plants, but grows above ground with age. It can grow into very old sago palms with  of trunk; however, the plant is very slow-growing and requires about 50–100 years to grow to this height. Trunks can branch several times, making multiple heads of leaves.Thunberg, Carl Peter. 1782.  Verhandelingen uitgegeeven door de hollandse maatschappy der weetenschappen, te Haarlem 20(2): 424, 426–427. The largest human-grown sago palm, at the Ryugeji Temple, in Shimizu, Japan ( west south-west of Tokyo), is  in height and  thick.


 Cultivation and uses 
Spread of Cycas revoluta is either by seed or by clones by removing parts of the base. It is one of the most widely cultivated cycads, grown outdoors in warm temperate and subtropical regions, or under glass in colder areas. It grows best in sandy, well-drained soil, ideally with some organic matter. It needs good drainage or it will rot. It is somewhat drought-tolerant and grows well in full sun or outdoor shade, but needs bright light when grown inside buildings. The leaves can whiten somewhat if moved from inside a building to full sun outdoors.


Sago
The pith (a material inside the plant) contains eatable starch, and is used for making sago. Before use, the starch must be carefully washed to clean out toxins inside the pith. Getting eatable starch from the sago cycad needs special care due to the toxic nature of cycads.

 Toxicity 
Cycad sago is extremely poisonous to animals (including humans) if eaten. Pets are a especially at risk, since they apparently find the plant very pleasant to eat.Suspected cycad (Cycas revoluta) intoxication in dogs, Botha CJ, Naude TW, Swan GE, et al.| J S Afr Vet Assoc |  1991 Clinical symptoms of eating the plant will develop within 12 hours, and may include vomiting, diarrhea, weakness, seizures, and liver failure or hepatotoxicity characterized by icterus, cirrhosis, and ascites. The pet may seem bruised, have nose bleeds (epistaxis), melena (blood in the stool), hematochezia (bloody straining), and hemarthrosis (blood in the joints). The ASPCA Animal Poison Control Center estimates a death rate of 50 to 75% when parts of a sago palm are eaten. If any quantity of the plant is eaten, a poison control center or doctor should be contacted immediately. Effects of eating the plant can include permanent internal damage and death.

All parts of the plant are toxic; however, the seeds contain the highest level of the toxin cycasin. Cycasin causes gastrointestinal irritation, and in high enough quantities, leads the liver to stop working.Selected poisonous plant concerns small animals, Knight MW, Dorman DC | Vet Med | 1997 | 92(3):260-272 Other toxins include Beta-methylamino L-alanine, a neurotoxic (toxic to the brain) amino acid, and an unidentified toxin which has been seen to cause paralysis in the hind limbs of cattle.Toxicology Brief: Cycad toxicosis in dogs, Hany Youssef| Veterinary Medicine | May 1, 2008 | 

 Gallery 

 References 

 Other websites 

 The Cycad Pages: Cycas revoluta 
 Sago Palm: University of Arizona Pima County Cooperative Extension
 The Sago Palm, Cycas revoluta by Phil Bergman
 Cycads: their evolution, toxins, herbivores and insect pollinators.  Schneider D, Wink M, Sporer F, Lounibos P.  Naturwissenschaften. 2002 Jul;89(7):281-94. Review.
 Microsporophyll
 Macrosporophyll
 Seeds
 Videos - Flavon's Wild herb and Alpine plants
 line drawing of Cycas revoluta, Manual of Vascular Plants of the Lower Yangtze Valley China Illustration fig. 31 
 line drawing of Cycas revoluta, Flora of China Illustrations vol. 4, fig. 2, 1-6