Dendrosicyos

Dendrosicyos socotranus

Dendrosicyos socotranus is a member of the gourd family ( Cucurbitaceae ). The species is the only representative of the genus Dendrosicyos. It occurs only on the island of Socotra and grows tree-like.

Features

Dendrosicyos socotranus grows tree-like one of the very few species of Cucurbitaceae. It is up to 7 m high and has a bottle-shaped trunk made ​​of soft wood ( Pachycaulie ). The strain reached a diameter of up to one meter. Numerous branches and small branches grow from the trunk, a contrast to other representatives of the habit bottle tree. The main stem grows sympodial: the shoot tip bends until it is no longer the highest point of the plant; from the highest point now arises a new shoot, which takes over the top growth. This process is repeated again and again.

The base consists largely of parenchyma. Embedded within it are small Xylemstränge that are networked together ( anastomosis ). This Xylemstränge possess a cambium, which forms secondary phloem. There is not a continuously active cambium, it is successively repeatedly trained on the periphery of a new cambium ( successive cambium ). Dendrosicyos is the first member of the gourd family, in which such a Folgemeristem was detected.

The leaves are about 10 cm long and wide, her blade edge is a little thorny. Sitting at the underside of leaves hair from two to seven cells, the two cells often include at the top cystoliths. The epidermal cells are lignified, the surface carries a thick Cutinschicht.

The flowers are in armblütigen inflorescences in the leaf axils. The species is monoecious, that is male and female flowers on one plant. The flowers are yellowish- orange with long corolla lobes. The fruits are ovoid and jump to maturity on. The seeds are approximately 6 mm in size.

The plant contains Dendrosycin, a Isocucurbitacin with unusual ring formation.

Dissemination and locations

Dendrosicyos socotranus is found only on the island of Socotra, an island off the Horn of Africa. It grows here in the bush. Due to the anatomical characteristics of strain ( much parenchyma ) and leaves is the kind well adapted to dry habitats.

System

The genus is placed in the subfamily Cucurbitoideae and here in the tribe Coniandreae within the Cucurbitaceae. Dendrosicyos the basalste clan within the tribe, their sister group to all other genera of the tribe.

Genus and species were first described by Isaac Bayley Balfour in 1882. The name means Dendrosicyos socotranus Cucumber Tree of Socotra.

Documents

• ME Olson: Stem and leaf anatomy of the arborescent Cucurbitaceae Dendrosicyos socotrana with comments on the evolution of pachycauls from lianas. Plant Systematics and Evolution, Volume 239, 2003, pp. 199-214, doi: 10.1007/s00606-003-0006-1