Welwitschia mirabilis ssp. namibiana

Common Name: Tree Tumbo

Family: Welwitschiaceae

Synonym(s): Welwitschia bainesii (Hook.f.) Carrière

Country of Origin: Namib Desert

Description: A single species of dioecious perennial with short stem and taproot native to S. Angola and SW African deserts, extending into mopane woodland. It is a long-lived plant, deriving moisture from sea-fog dew. Winged seeds germinate in wet years, the cotyledons photosynthesizing for 1.5 years; foliage leaves decussate with respect to cotyledons, of indefinite growth (up to 13.8 cm per year), wearing away at the tips, the apical meristem being lost. Fertile buds are produced on the 'crown' between the leaf bases.

Reproductive shoots dichasial, insect pollinated. Females subtended by cone-scales making up a red cone and consisting of a nucellus enclosed in an integument and another layer derived from two confluent primordia ('perianth') with 2 'bracts'; megaspore mother-cell grows into a prothallus without archegonia. Male pollen-bearing structures subtended by cone-scales making up a red cone and consisting of 2 lateral 'bracts' and a 'perianth' formed by the union of 2 bract-like organs, 6 microsporangiophores and a sterile unitegmic ovule; male gametophyte merely a tube-nucleus, an abortive sterile cell and a cell giving rise to 2 sperm nuclei. As pollen tubes penetrate prothallus, prothallial tubes grow up to meet them in the nucellus, fusion of females and males allegedly occurring in the tubes; many zygotes but only one matures and is dispersed with 'perianth' as a wing.

Somewhat challenging in cultivation; appreciating warmth, strong sun, large pots, and more water than might be expected. Never allow soil to dry completely. Propagated by seeds.

USDA Zone: 9-11

Accession #: 201100223

Accession Date: 2011-07-12 00:00:00

Bloom Status: 🪴 Not Flowering

Location: 2207

Quantity: 2

Source: Joe Lamacchia (swap for some 199700061)

Provenance:

These plants came in trade from Joseph Lamela-Macchia of New Jersey; a new accession number was added in 2011. There are two larger original plants in this accession: a female from Cactus Data Plants and a male from Grigsby Cactus Gardens.

Culture: An excellent article by Anna Senters can be found here

Division: Gnetophyta

Class: Gnetopsida

Subclass: Gnetidae

Order: Welwitschiales

Family: Welwitschiaceae