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''Dendrosicyos'' is a monotypic genus in the Cucurbitaceae plant family. The only species is ''Dendrosicyos socotranus'', the cucumber tree. The species is endemic to the island of Socotra in Yemen, and is the only species in the Cucurbitaceae to grow in a tree form. == Features == It has a bulbous trunk and a small crown. It was first described by Isaac Bayley Balfour in 1882. A recent molecular phylogenetic analysis of the family Cucurbitaceae found that the ''Dendrosicyos'' lineage is about twice as old as the island, and thus seems to be an island relic of a progenitor lineage that went extinct on the mainland. The leaves are nearly round, covered with fine bristles, and slightly toothed. The yellow flowers (3 cm), males and females are present on the same plant for cross pollination. It reproduces only by seed. Fruits (3 x 5 cm) are green, turning brick-red when ripe. Seedlings subjected to overgrazing and regeneration may be compromised over time, except for seedlings protected from goats by ''Cissus subaphylla''. The species is considered vulnerable. In Soqotri, its name is ''qamhiyn''. Contrary to what its region of origin would suggest, ''Dendrosicyos socotrana'' responds well to a being drenched and fertilized, if the temperature is greater than 20 °C. Individuals in their natural habitat can attain 10 feet/3 m in height. Trunks are succulent, but not bottle-shaped when young. The plant produces flowers when five years old. 〔(''Dendrosicyos socotrana'': A tree squash extraordinaire )〕 ''Dendrosicyos socotranus'' has a bottle-shaped base of fibrous wood (pachycaul). The trunk reaches a diameter of up to one meter. Numerous small twigs and branches grow from the stem, the bottle tree growth form making it distinctive. The base consists largely of parenchyma. In it are embedded small xylem strands that are linked to each other (anastomosis). These xylem strands have a cambium, and a secondary phloem forms. There is not a consistently active cambium - it will always be sequentially formed on the periphery of a new cambium (cambium successively). ''Dendrosicyos'' is the first member of the Cucurbitaceae, in which such meristem has been demonstrated. The leaves are about 25 cm long and wide, its leaf edge being slightly thorny. On the underside of the leaves are trichomes of from two to seven cells, the cells often containing two cystoliths. The epidermal cells are lignified, the surface carries a thick cells however secrete. The flowers occur in the leaf axils. The species is monoecious - male and female flowers on one plant. The flowers are yellowish-orange with long petals and the fruits are ovate. The seeds are about 6 mm. The plant contains dendrosycin, an iso-cucurbitacin with an unusual ring formation.〔HA Hussein, O.B. Abdel-Halim, S.M. Marwan, A.A. El-Gamal, R. Mosana. Dendrocyin: an isocucurbitacin with novel cyclic side chain from ''Dendrosicyos socotrana'' Phytochemistry, Volume 65(18), 2004, p. 2551-2556. 〕 == Proliferation and locations== Described in 1882 by Isaac Bayley Balfour, the species is generally described as endemic to the island of Socotra, although some sources (1887) state that it was present on the African continent in Djibouti. It is quite abundant on the dry parts of the island of Socotra, associated with ''Croton socotranus'' in the plains, and on calcareous soils to 500 m elevation. The species is well-adapted to dry sites. It is widely distributed in several vegetation types but has a rather fragmented distribution; over large areas there are only isolated trees or small relict populations, whilst in other areas it is relatively abundant. There are a few trees on the island of Samhah, but none on Darsah or Abd al Kuri. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dendrosicyos」の詳細全文を読む スポンサード リンク
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