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Accepted Scientific Name: Cycas revoluta Thunb.
Nova Acta Regiae Soc. Sci. Upsal. 4: 40 1783
Origin and Habitat: Garden origin (Nursery produced cultivar). The natural species id endemic to Japan (Ryukyu and other islands off southern Kyushu,) and china Fujian (Lianjiang Xian, Ningde Xian, and some islands).
Cycas revoluta Thunb.
Nova Acta Regiae Soc. Sci. Upsal. 4: 40 1783
- Cycas revoluta Thunb.
- Cycas miquelii Warb.
- Epicycas miquelii (Warb.) de Laub.
- Cycas revoluta var. brevifrons Miq.
- Cycas revoluta f. cristata hort.
- Cycas revoluta var. planifolia Miq.
- Cycas revoluta var. prolifera Siebold & Zucc.
- Cycas revoluta var. robusta Messeri
ENGLISH: Crested Sago Palm, Crested Sago Cycad, Crested Cycad
Description: Cycas revoluta is a low growing single trucked cycad, topped with whorled feathery leaves. Eventually, offsets begin to grow at the base of mature specimen, and occasionally in the crown producing multiple heads of leaves. The specific epithet “revoluta” refers to the the revolute (curled back) nature of the leaflets; the edges roll under the leaflet. Younger plants look like ferns with rosette of leaves coming from a stem near the ground. This is the most widely cultivated of the cycads.
Crested form: The crested sago palm (Cycas revoluta f. cristata) is a very rare, slow-growing and highly priced crested cycads forming odd sculptural shapes. Its stems fan out and can get very big making a spectacular specimen. The crested form - despite to its beauty - is still very rare, pricey and sought after by collectors.
Stem (trunk): Fan shaped, slowly forming brain-shaped mound that can reach a considerable size (up to 1 m tall and in diameter, or more). The stems are rough and retain the old leaf bases of previous leaves, about 20-25 cm 10-25 (or more cm thick).
Leaves: Long-lived, feather like growing in a circular pattern at top of trunk , 1-pinnately divided up to 90 cm long (or longer if not grown in full sun), leaflets narrow, with a sunken midrib and the margins rolled downward very dark glossy green or dark olive green, stiff and pointed, and about 10 cm long. The basal leaflets are gradually reduced to spines (whereas the similar Cycas circinalis does not have spines at the leaf base). It produce a periodic "flush" of new leaves, called a "break". The leaves produced in crested stems are often smaller and rarely overshoot 50 cm in length.
Flowers: Dioecious; reproductive clusters around frond bases.
Female inflorescense: The female cone is cabbage-shaped, gold or tan-yellow in color borne on small whitish miniature feather like modified leaves. It will slowly open up when receptive to pollen and later forms a tightly packed seed head.
Male inflorescence (cones): Large and erect, pineapple shaped.
Blooming season: Females and male specimens produce "cones" in May when it is time to pollinate.Wind, bees, or insects can pollinate the plants.
Seeds: Large, plum-like, pale yellow-tan, about 3 cm across. Seed develop over the summer and are ready to be removed in January or February. A female plant cannot produce viable, fertile seed unless it is pollinated.
Remarks: Cycas revoluta usually known as the "Sago Palm" is actually related to conifer and Ginko trees and is one of the most primitive living seed plants (a living fossil). Cycads have changed very little in the last 200 million years. Fossils have been found on almost every continent on the planet. But most people don’t realize that it is not a palm at all.
Subspecies, varieties, forms and cultivars of plants belonging to the Cycas revoluta group
Bibliography: Major references and further lectures
1) Wikipedia contributors. "Cycas revoluta." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 6 May. 2014. Web. 29 Jul. 2014.
2) Whitelock, Loran M. “The Cycads.” Timber press 2002
3) Hill, K.D. 2010. Cycas revoluta. The “IUCN Red List of Threatened Species”. Version 2014.2. <www.iucnredlist.org>. Downloaded on 29 July 2014.
4) Harrison, Lorraine . “RHS Latin for gardeners.” United Kingdom: Mitchell Beazley. 2012
5) Muller-Esneault, Susan "Cycas Revoluta: The Sago Palm, or Cycad Toxicity". Critterology.com. 2009
6) Wu Zhengyi, Peter H. Raven, Deyuan Hong (Hrsg.): "Flora of China. Volume 5: Ulmaceae through Basellaceae," Science Press/Missouri Botanical Garden Press, Beijing/St. Louis 2003
7)Jules Janick, Robert E. Paull “The Encyclopedia of Fruit and Nuts” CABI, 2008
9)Haynes J.L, “World List of Cycads: A Historical Review” IUCN/SSC Cycad Specialist Group, 2012
Cultivation and Propagation: It is easy to grow, tolerating dry periods, and light frosts. It prefers bright light exposure but colour bleaches when in full sun; best with some protection from afternoon heat. Needs a well drained spot, with deep soil, but will still thrive in less than ideal conditions, not tolerant of alkaline soils. Usually slow growing, however good conditions can speed it up considerably. Because of its growth habit, fertilize only when terminal bud begins to swell, indicating the start of the annual growth cycle.
Maintenance: Minimal; removal of offsets if desired, removal of spent fronds.
Specific tips for growing the crested forms: The crests are frequently grafted onto columnar cacti but are easily grown on their own roots. Any normal shoots should be removed to promote the growth of the crest.
Propagation: Seed or offshoots (or "pups" ). The advantage of the "pups" is that you will know its sex, for seedlings you will have to wait several years until the plant flowers to find out. After fertile seeds are collected, they usually need several months of storage before the inner embryo is ready to germinate. Therefore, it is best to clean the seeds of external fruit and set them aside before attempting to propagate the seeds.
Warning: Best kept away from paths, since the leaves are quite stiff. The plants contain alkaloids of carcinogens and also an amino-acid that causes chronic nervous disorders. Regular consumption of the plant leads to severe health problems and death. Poisonous Parts: Fleshy seeds, leaves, unprocessed flour from stem pith. Symptoms: Vomiting, diarrhea, headache, dizziness, seizures.
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