दक्षिणपश्चिम अफ्रीका के शुष्क क्षेत्रों के उत्सुक संयंत्र में एक गहरे नलोट के साथ एक गहरी टैपरोट और दो बड़े लगातार वुडी पट्टे की तरह पत्तियों की तरह एक गहरे टैपरोट के साथ एक यार्ड-उच्च और यार्ड-व्यापी ट्रंक होता है; एक वनस्पति से जीवित अवशेष गायब हो गया; कुछ 700-5000 साल का हो सकता है

welwitschia's Usage Examples:

Gnetales: Hooker, " On Welwitschia mirabilis," Trans.

In 1906 he gave an account of the early stages of development of the male and female organs and, among other interesting statements in regard to the general biology of Welwitschia, he expressed the opinion that, as Hooker suspected, the ovules are pollinated by insect-agency.

The megaspore of Welwitschia is filled with a prothallus-tissue before fertilization, and some of the prothallus-cells function as egg-cells; these grow upwards as long tubes into the apical region of the nucellus, where they come into contact with the pollen-tubes.

In a supplement to the systematic work of Engler and Prantl the well-known name Welwitschia, instituted by Hooker in 1864 in honour of Welwitsch, the discoverer of the plant, is superseded by that of Tumboa, originally suggested by Welwitsch.

Welwitschia (Tumboa).

In certain species of Gnetum described by Karsten the megaspore contains a peripheral layer of protoplasm, in which scattered nuclei represent the female reproductive cells; in Gnetum Gnemon a similar state of things exists in the upper half of the megaspore, while the lower half agrees with the megaspore of Welwitschia in being full of prothallus-tissue, which serves merely as a reservoir of food.

In Welwitschia also the megaspore is filled with prothallus-tissue, but single egg-cells take the place of archegonia.

The three existing genera, usually spoken of as members of the Gnetales, differ from one another more than is consistent with their inclusion in a single family; we may therefore better express their diverse characters by regarding them as types of three separate families-0) Ephedroideae, genus Ephedra; (2) Welwitschioideae, genus Welwitschia; (3) Gnetoideae, genus Gnetum.

Ovules naked, rarely without carpellary leaves, usually borne on carpophylls, which assume various forms. The single megaspore enclosed in the nucellus is filled with tissue (prothallus) before fertilization, and contains two or more archegonia, consisting usually of a large egg-cell and a small neck, rarely of an egg-cell only and no neck (Gnetum and Welwitschia).

In the Gnetaceous Welwitschia it possesses a vegetable type whose extraordinary peculiarities make it seem amongst contemporary vegetation much as some strange and extinct animal form would if suddenly endowed with life.

welwitschia's Meaning':

curious plant of arid regions of southwestern Africa having a yard-high and yard-wide trunk like a turnip with a deep taproot and two large persistent woody straplike leaves growing from the base; living relic of a flora long disappeared; some may be 700-5000 years old