Welwitschia mirabilis: a plant from Tatooine?

For many of us, the first movie in the Star Wars series was a major media event. On Tatooine, Luke Skywalker's home planet, one scene, where the two 'droids were going up a rather dry gully that was devoid of plants, Welwitschia would have fit in quite nicely. To me, it is one of the strangest plants in the world. Ever since I was "introduced" to Welwitschia mirabilis in Dr. Donald Foard's Morphology of the Plant Kingdom class at UCLA, I had wanted to grow this rather alien looking plant.

In the next few years, I was able to visit several institutions that had either plants growing or an exhibit. This help me to broaden my knowlege about how others were growing Welwitschia. It is interesting how many cultural methods were used. I will have a separate page of these visits at a later date. Whether the exhibits are still around, is unknown at this point given that I saw them in the mid 1960's.

In 1963, seed from Walvis Bay, South Africa (now Namibia) was obtained through the generosity of a fellow student, Albert J. Hill. They were sown in quart milk cartons in a pure decomposed gravel medium where all of the fine material had been sifted out. The tall milk cartons were to accommodate the long tap root that all of the literature we read talked about. Germination was rapid-within two weeks, seedlings had emerged. Within several weeks, the two leaves were emerging between the two cotyledons.

Panel 1 This is a close-up of a seedling growing in a quart milk carton about 3 months old in the UCLA Plant Physiology greenhouse. The decomposed granite gravel grains are between 1/8 to 1/4 inch in size. The only two leaves the plant will ever have during its entire life are visible as two small triangles between the long purplish-red cotyledons.

Problems were encountered with the plants in these milk cartons as the water didn't drain completely from the bottom holes, resulting in a saturated layer of gravel near the bottom. When the roots reached this layer, the tips rotted and the rot spread up, eventually killing the seedlings. All but three of the fourteen original Walvis Bay seedlings were lost.

(check notebook for dates)

The three remaining seedlings were transplanted to a specially designed pot and were placed outside against a south facing fence. It was hoped that the lower humidity outside would aid growth, even though it was winter. When one seedling died and half of another began to die, the plants were returned to greenhouse conditions, being placed where maximum sun would be obtained. Regular watering and inline fertilization were started. Within a few weeks, recovery and rapid growth were evident.

can insert pix of #2 here.

Seeds were also obtained from Portuguese sources- the Botanical Gardens at Coimbra, Portugal and the one at Nova Lisboa (now Huambo), Angola. Correspondence with Coimbra indicated that their seed was collected in habitat each year in extreme southwestern Angola near Cabo Negro (Mossamedes), and they didn't have any growing in Portugal.

Growth measurements taken for about ten years indicated that the Angolan population grew about twice as fast as the Namibian (Walvis Bay) population. The habitat in Angola is definitely more mesic-grassland savanna, versus extreme desert conditions at Walvis Bay.

Panel 2 #5 21 Febuary 1966- about 15 months after planting directly into the pot.

At UCLA, growth was rapid slowing only during the winter months due to the short photoperiod. With the coming of spring and longer days, growth began, indicated by a small band of light green emerging from the base of the leaves.

Panel 3 What later turned out to be the beginnings of a strobilus, this small bump shows the start of reproductive activity.

Panel 4 The first strobilus, which later turned out to be staminate (male). The plant (#9- Angolan population) was 3 years and 9 months old at this time. This was the only plant to produce cones while grown in the same location (UCLA).

Panel 6 Emerged pistillate (megasporangiate) strobilus on Plant #2 (Walvis Bay population) at 12 years and 7 months from seed planting.

Panel 7 The development of the pistillate (megasporangiate) strobilus is very similar to that of the staminate (microsporangiate) strobilus except that the developing cones are much larger, this difference being evident very early. Again, a droplet of nectar can be seen at the tip of the pollination tubes (microtubules). Thus, the stage is set for possible plant-insect interaction. And this is a gymnosperm!

Pollination was effected by using the nectar as a carrier, dabbing first the stamens with a nectar wetted glass rod and then dabbing the ends of the microtubules. Due to the abundance of nectar, the nectar was removed from most of the microtubules first so that the pollen-nectar mix would not get over diluted. This process was repeated several times. (check times, as nectar is withdrawn at certain times.)

 

Panel 8 A mature megasporangiate strobilus. This was the first one produced on Plant #2 on 12 November 1976. A total of 57 full seeds resulted.

Panel 9 This is a close up of the base of the mature female strobilus. The scales have begun to dry and loosen. Seeds are released as the cone scales loosen and detach.

The process of growing Welwitschia from seed to seed, in our case took about 13 years and was published in 1980 by Leo C. Song, Jr. in the Cactus & Succulent Journal (U.S.) 52(1, 2): 30-32 & 68-73. The Montreal Botanical Garden also did it in 13 years (Teuscher, 1951), and the Stellenbosch Botanical Garden in 23 years (Herre, 1954). Authors cited are referenced in the Cactus & Succulent Journal article. Another seedling grown entirely at Cal State Fullerton from our seeds produced a megasporangiate strobilis in about 10 years. The longer times for some of our plants probably resulted in part from their stay in a poorly heated and lit residential greenhouse in the early 1970's. The secret is to give the plant abundant light and heat with a fast draining growing medium. Plants can be put on a regular inline fertilization program. With this treatment, growth is rapid. The first cones seem to be produced when the plant base reaches a certain minimum size- about XX cm wide. Times to produce the first cones vary due to the wide variations in cultural methods. Methods that favor rapid strong growth will bring the plants to the reproductive state sooner. Signs (coning signs) are slight buldges occurring near the outer edges of the center bracts which may or may not show cracking. One plant (16) showed these signs after only one year and two months. (See Panel 3 Use your browser's Back button to get back here). This is not always the case, however, as the last of the original seven (The Magnificent Seven?) finally produced "her" first cone at about 30 years! This was one of two surviving plants from Walvis Bay.

Our plants have been used in several research projects. One done by Irwin Ting that showed that contrary to earlier reports of crassulacean acid metabolism (CAM) being present, showed no indication of CAM, but what turned out to be carbon recycling (cite article here). That is, under extreme drought stress, Welwitschia closes its stomates and refixes respiratory carbon dioxide, produced at night, trapped in the intercelluar spaces during the daylight. However, the plants can eventually die from total lack of water if their root system cannot reach deep ground water or pick up water from fog drip.

Another project, entitled, "The Mostly Male Theory of Flower Evolutionary Origins: from Genes to Fossils" by Michael w. Frolich and Davis S. Parker, is in press in Systematic Botany. Looking at the DNA for cladistic analysis, (more later), specifically for the LFY gene. This material and additional material obtained from the Huntington Botanical Gardens was critical in the execution of this project (Frolich, personal communication).

We have been producing seed since the early 1970's and when supplies permit, distribute seed on request to educational institutions and botanical gardens. Many educational institutions have plants grown from seed produced here and we are indeed greatly satisfied that many more people can see and touch this most interesting plant.