The stem of this cycad resembles that of a palm, and grows 4–10 meters tall and up to 45 cm in diameter. The large photosynthetic leaves have spiral arrangement on the stem and are interspersed with many brown, hairy, triangular scale-like leaves. The photosynthetic leaves are pinnate, dark-green, somewhat glossy, and usually 150—300 centimeters long, with 60-120 leaflets per side. The leaflets are c. 17 cm long, lanceolate, with a slightly bent margin, and a midrib that is more prominent on the paler lower surface. The leaf-stalk is 40–50 cm long, and has two rows of spines along almost its whole length. The emerging leaves are hairy and show involute vernation; and the young leaves have a distinct bluish tint, which distinguishes it from its relatives C. rumphii and C. circinalis. The pollen cone is spindle-shaped, 30–60 cm high and 10–15 cm in diameter, and varies in color from orange to pale brown. The pollen cone scales have a sharp apical spine. The ovulate cones are composed of overlapping, yellow, hairy megasporophylls, each 29—32 centimeters long, with 5-13 marginal teeth per side, and bearing 4-10 ovules along their edges. The seeds are ovoid, 50—60 millimeters in size with a red-brown fleshy seed coat, and a spongy endocarp. This spongy endocarp is characteristic of this species, and allows the seeds to float.[3][2]
General habit
Growing point, showing spiny petioles and young cataphylls
The Madagascar cycad is found on Madagascar and the nearby islands of Comoros, Mayotte and the Seychelles. It is also found along the coasts of Kenya, Mozambique, and Tanzania.[1] According to de Laubenfels and Adema, the plant is also found in Sri Lanka, but this may be confusion with the closely related Cycas circinalis.[2] The tree grows 200 meters above sea level, in light forests and their borders, or near coastal sites on sandy soil or coral formations. These areas have annual precipitations varying from 1000 to 3000 millimeters per year.[citation needed]
The plant is quite rare both as an individual and in group communities, and populations were impacted by collectors, the growth of the seaside resorts and agriculture development[citation needed]. However, there is no immediate threat to this species, and it is classified as Least Concern on the IUCN Red List.
Cultivationedit
As a relatively fast-growing cycad, Cycas thouarsii is occasionally grown in horticulture as a specimen plant. It requires moist but well-drained soil, and will tolerate shade, partial shade, and sun (with sufficient humidity). It is hardy to only a very light frost but can tolerate brief exposure to temperatures down to −3.9 °C (25 °F - USDA hardiness zone 9b) but this results in leaf scorching.[4]
Use as foodedit
Although toxic, the seeds are eaten on the Comorian island of Ngazidja, particularly in the regions of Hamahame and Washili, where the plant, known as ntsambu, has cultural significance. The cyanotoxins are removed from the seeds by a process of repeated washing, fermentation and drying, which renders them edible.[5]
Referencesedit
^ abGolding, J.; Hurter, J. (2010). "Cycas thouarsii". IUCN Red List of Threatened Species. 2010: e.T41940A10606292. doi:10.2305/IUCN.UK.2010-3.RLTS.T41940A10606292.en. Retrieved 20 November 2021.
^ abcde Laubenfels, D. J.; Adema, F. (1998). "A taxonomic revision of the genera Cycas and Epicycas Gen. Nov. (Cycadaceae)". Blumea. 43: 351–400.
^. plantnet.rbgsyd.nsw.gov.au. Archived from the original on 2015-03-09. Retrieved 2017-08-01.
^"Cycas thouarsii at San Marco growers". San Marcos Growers. Retrieved 18 April 2019.
^Walker, iain. (2012). "Ntsambu, the foul smell of home: Food, commensality and identity in the Comoros and in the diaspora". Food and Foodways. 20 (3–4): 187–210. doi:10.1080/07409710.2012.715962. S2CID 143069018.
January 01, 1970
cycas, thouarsii, madagascar, cycad, evergreen, arborescent, cycad, genus, cycas, named, after, french, botanist, louis, marie, aubert, petit, thouars, 1758, 1831, madagascar, cycad, conservation, status, least, concern, iucn, scientific, classification, kingd. Cycas thouarsii the Madagascar cycad is an evergreen arborescent cycad in the genus Cycas It is named after a French botanist Louis Marie Aubert du Petit Thouars 1758 1831 Cycas thouarsiiMadagascar cycad Conservation status Least Concern IUCN 3 1 1 Scientific classification Kingdom Plantae Clade Tracheophytes Clade Gymnospermae Division Cycadophyta Class Cycadopsida Order Cycadales Family Cycadaceae Genus Cycas Species C thouarsii Binomial name Cycas thouarsiiR Br Range of Cycas thouarsii 2 Synonyms Cycas madagascariensis Miq Cycas circinalis f thouarsii R Br Engl Cycas circinalis subsp trigonocarpoides J Schust Cycas circinalis subsp madagascariensis Miq J Schust Cycas comorensis BruantCycas kirkii J Schust Cycas thuarsii R Br ex DC Cycas wendlandii Sander Contents 1 Description 2 Habitat ecology and conservation status 3 Cultivation 4 Use as food 5 ReferencesDescription editThe stem of this cycad resembles that of a palm and grows 4 10 meters tall and up to 45 cm in diameter The large photosynthetic leaves have spiral arrangement on the stem and are interspersed with many brown hairy triangular scale like leaves The photosynthetic leaves are pinnate dark green somewhat glossy and usually 150 300 centimeters long with 60 120 leaflets per side The leaflets are c 17 cm long lanceolate with a slightly bent margin and a midrib that is more prominent on the paler lower surface The leaf stalk is 40 50 cm long and has two rows of spines along almost its whole length The emerging leaves are hairy and show involute vernation and the young leaves have a distinct bluish tint which distinguishes it from its relatives C rumphii and C circinalis The pollen cone is spindle shaped 30 60 cm high and 10 15 cm in diameter and varies in color from orange to pale brown The pollen cone scales have a sharp apical spine The ovulate cones are composed of overlapping yellow hairy megasporophylls each 29 32 centimeters long with 5 13 marginal teeth per side and bearing 4 10 ovules along their edges The seeds are ovoid 50 60 millimeters in size with a red brown fleshy seed coat and a spongy endocarp This spongy endocarp is characteristic of this species and allows the seeds to float 3 2 nbsp General habit nbsp Growing point showing spiny petioles and young cataphylls nbsp Unfurling leaves showing involute vernation nbsp Pollen cone nbsp Seed nbsp Coralloid roots these contain nitrogen fixing cyanobacteriaHabitat ecology and conservation status editThe Madagascar cycad is found on Madagascar and the nearby islands of Comoros Mayotte and the Seychelles It is also found along the coasts of Kenya Mozambique and Tanzania 1 According to de Laubenfels and Adema the plant is also found in Sri Lanka but this may be confusion with the closely related Cycas circinalis 2 The tree grows 200 meters above sea level in light forests and their borders or near coastal sites on sandy soil or coral formations These areas have annual precipitations varying from 1000 to 3000 millimeters per year citation needed The plant is quite rare both as an individual and in group communities and populations were impacted by collectors the growth of the seaside resorts and agriculture development citation needed However there is no immediate threat to this species and it is classified as Least Concern on the IUCN Red List Cultivation editAs a relatively fast growing cycad Cycas thouarsii is occasionally grown in horticulture as a specimen plant It requires moist but well drained soil and will tolerate shade partial shade and sun with sufficient humidity It is hardy to only a very light frost but can tolerate brief exposure to temperatures down to 3 9 C 25 F USDA hardiness zone 9b but this results in leaf scorching 4 Use as food editAlthough toxic the seeds are eaten on the Comorian island of Ngazidja particularly in the regions of Hamahame and Washili where the plant known as ntsambu has cultural significance The cyanotoxins are removed from the seeds by a process of repeated washing fermentation and drying which renders them edible 5 References edit a b Golding J Hurter J 2010 Cycas thouarsii IUCN Red List of Threatened Species 2010 e T41940A10606292 doi 10 2305 IUCN UK 2010 3 RLTS T41940A10606292 en Retrieved 20 November 2021 a b c de Laubenfels D J Adema F 1998 A taxonomic revision of the genera Cycas and Epicycas Gen Nov Cycadaceae Blumea 43 351 400 Cycas thouarsii plantnet rbgsyd nsw gov au Archived from the original on 2015 03 09 Retrieved 2017 08 01 Cycas thouarsii at San Marco growers San Marcos Growers Retrieved 18 April 2019 Walker iain 2012 Ntsambu the foul smell of home Food commensality and identity in the Comoros and in the diaspora Food and Foodways 20 3 4 187 210 doi 10 1080 07409710 2012 715962 S2CID 143069018 Retrieved from https en wikipedia org w index php title Cycas thouarsii amp oldid 1212238354, wikipedia, wiki, book, books, library,
