Accession Data

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.

Cone-bearing shoots dichasial, insect pollinated. Females subtended by cone-scales making up a red cone and consisting of a single 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 microsporangia subtended by cone-scalesmaking 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.

Accession Data

USDA Zone: 9-11

Accession #: 199700061

Accession Date: 1997-09-18 00:00:00

Bloom Status: 🪴 Not Flowering

Location: 2207

Quantity: 4

Source: Seed - UC-Davis, Univ of Colo. - Boulder

Culture: Difficult to cultivate requiring desert conditons and room to accomodate its long taproot. Propagated by seeds.

An excellent article by Anna Senters can be found here

Classification

Division: Gnetophyta

Class: Gnetopsida

Subclass: Gnetidae

Order: Welwitschiales

Family: Welwitschiaceae

Flowering Data:

This accession has been observed in bloom on:
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
2009
2008

References

  1. The Plant Book, Mabberly, 1987
  2. Photos 3 & 4 courtesy Dr. John Silander, EEB, July 2004 - all rights reserved.
  3. The Plant List (2013). Version 1.1. Accessed 26 February 2015.
  4. WCSP (2015). World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. Accessed 26 February 2015.
  5. Senters, Anna E., Welwitschia mirabilis cultivation in AERGC Newsletter, Vol 10 (2), Summer 1997 p.5-7. Last accessed on Monday, January 23, 2017.
  6. Welwitschia Propagation at Burger's Onion (Matt's blog). Last accessed on Wednesday, December 20, 2017.

Images

Welwitschia mirabilis ssp. namibiana