01 December 2013

DORSTENIA GIGAS

DORSTENIA GIGAS is one of nearly 170 species of the family MORACEAE, the family of the figs and mulberries. FICUS is the genus of the figs and MORUS that of the mulberries.

DORSTENIA with its species is "A LIVING FOSSIL". Why? Because of the "flowers"!

The SPERMATOPHYTA were the first plants on earth to have a " seed". They are called GYMNOSPERMAE, "naked seeds", plants like our todays araucarias, firs, larches, spruces..., and their seeds and sexual organs were naked, meaning open to the atmosphere. They had and have no flowers - in the meaning of flower as you and I understand it.
The next step was the birth of the ANGIOSPERMAE, "covered seeds", plants like our cacti, orchids, palms, roses, weeds..., and their seeds and sexual organs were enclosed with plant tissue, "hidden" from the atmosphere and "our eye".
The most primitive species were plants like our todays magnolias. And plants like our DORSTENIA were the first ones to have something like a flower bottom, bearing the flower petals around the bottom and female and male sexual organs on the buttom. This construction is called HYPANTHODIUM. It developed during evolution in flowers like our apple flower and fruit. A marvellous wounder.
Female flowers and male flowers grow on the same plant. They are self sterile so that you will need two different plants to get seeds. Every female flower produces one fruit bearing one seed.

DORSTENIA GIGAS is the most beautiful species of the genus. The bigger and older it grows the more beautiful it becomes.

It dwells on the socotran archipelago and seems only be found at Sokotra, the biggest island, around 240 km east of the Horn of Africa and 380 km south of the arabian peninsula.

GEORG AUGUST SCHWEINFURTH, a german botanist, ethnologist and palaeontologist, of riga, latvia, discovered it on his expedittion to Sokotra and published it 1881.
 The natives call it KARTAB, arabian for "stills the thurst". It reaches a height of 2,5 m and breadth of 1,5 m. It is a pachycaul succulent and becomes a bottle shaped "tree" growing older and older.
You may find elsewhere some whisper of different forms which show different growing shapes... I have never seen different forms in nature or culture. Future may tell...

Where it grows... We must keep in mind that the natural habitats are used by the natives and their goats and other animals so that this grazing must have a stark impact on the occurence of DORSTENIA GIGAS. So the distribution today may be very different from former times.
The species grows in the HAGGHER MOUNTAINS in the central western part of Sokotra from around 600 m up to 1100 m. The mountains consist of granite.
On other habitats in the mountains and outside of these they grow on lime stone. There in crevices and cracks eroded by rain, water and wind where humus can accumulate they find their niche.

Water comes with the monsoons, the North-Eastern Monsoon in April and May, and the South-Western Monsoon from August to November. Around 1000 mm rain pour down over one year.

Temperature is moderate and never drops under 15 C and goes up to 34 C.




My DORSTENIA GIGAS plants are cultivated the same way as my ADENIUM, DISCOCACTUS, MELOCACTUS, PACHYPODIUM and UEBELMANNIAS.

The substrate is my typical mineral substrate. For one half of my plants I use this mixture which is rich in GRANITE & GNEISS, for the other half I add an extra portion lime to the standard substrate. Time might tell if there will be any difference...

Fertilizer is added in a very very very low concentration to the water. Watering depends of the weather and the growing period of the plants.

Allthough some growers tell that the plants are hardy down to 4 C, I "do not let them down" and give them at least 15 C. In winter they stand on an eastern window with a heater nearby. Watering will be done once or twice a month if they bear their leaves over winter. Generally they will be kept absolutely dry like most succulents.

Flowering begins in autumn and may endure to spring.