Accepted Scientific Name: Welwitschia mirabilis Hook.f.
Gard. Chron. 1862: 71 1862
Origin and Habitat: It is endemic to Namibia to Angola in a narrow strip, about 1 000 km along up the coast from the Kuiseb River in central Namibia to Mossamedes in southern Angola. The plants are seldom found more than 100 to 150 km from the coast, and their distribution coincides with the fog belt.
Habitat: This plant is confined to the cost of the Namib desert. The plants occurs scattered in patches on sandy stony plains under extreme xerophytic conditions. The plant is perfectly adapted to live in the fog zone and draws all its water from the fogs which roll in from the sea. In most parts of its habitat the rainfall does not exceed 25 mm x annum.
Synonyms:
See all synonyms of Welwitschia mirabilis
Description: Welwitschia mirabilis is a very curious relict gymnosperm with only a single pair of extremely wide, persistent adult leaves. Its barrel-shaped woody stem or crown (caudex) in the center is deeply imbedded in the ground and rooted by a very long tap root. During all its long life-cycle the hypocotyl continues to enlarge forming a short “trunk”, for this reason it is said it is a persistent seedling. It is a very long living plant and some specimens is assumed to be 1000 (or even more) years old. It is one of the most bizarre of all the seed plants often described as unlike any known plant on earth.
Trunk (hypocotyl): Woody broadly obconic or turbinate, concave on the top, more or less circular or elliptic in horizontal section, rising 20-30 above the ground, 30-90(-120) cm in diameter at the top, most of which is underground and tappering down to its main taproot. It is covered by thick corrugated cork. The stem widens with age to become a concave disc from which grow small ramified branch systems that serve only to bear pollen and seed cones.
Root: It has a long tap root that is elongate, usually branching near the apex with some pronounced lateral roots, and a network of delicate spongy roots.
Leaves: Parallel-veined, leathery, fibrous and curled, strap-shaped up to 2 mm thick and 2 or more meters in length. Like grass leaves, their meristematic region is at the base so they continually grow even though their tips get worn off by abrasion. In fact, the leaves lie on the ground and as they flap about in the wind they become split and frayed. Leaves typically grow at a rate of 8-15 cm per year on mature plants, some of which have been found with leaves measuring 1.8 m wide and 7(-9) m long, suggesting potential ages of 500-1000 years.
Flowers: Welwitschia plants are dioecious, produces separate, scaly male and female cones on separate male and female plants.
Male cones (strobili): Salmon-coloured , oblong, cone-like, 1-4 cm long, 5-7 mm wide, and on a pedicel 2-5 mm long, with bracteoles1-3mm long.
Female cones (strobili): Larger than male strobili – 3,5-8 cm long, 2-3 cm wide, with outer bracteoles 5 mm long and inner bracteoles 8 mm long.
Seeds: 36 x 25 mm with a large papery wing. They are dispersed by wind, in spring, when the female cone disintegrates. The seeds remain viable for a number of years. They germinate only if fairly heavy rain is spread over a period of several days.
Cultivation and Propagation: Difficult to cultivate it is thought that it requires desert conditions and room to accommodate its long tap-root, so they are mostly underwatered to prevent rot and often thei die from underwatering.
Be aware that Welwitschia are not succulent plants, so should not be allowed to dry completely at any time. During the summer, if grown in full sun they can be drenched thoroughly, allowing to become slightly dry between waterings, but care should be taken that the soil does not dry out completely. It is thought that they must have a very deep pot to thrive, but it is now known that they will live quite nicely in a standard depth pot. The will slow their growth when trasplanted.
During the natural resting period in winter, watering should be reduced, and increased again in late spring when the weather warms up again.
Exposition: Light: Bright light or full sun.
Propagation: By seeds.