Photo 15436070, (c) Jan-Hendrik Keet, some rights reserved (CC BY-NC), uploaded by Jan-Hendrik Keet

Attribution © Jan-Hendrik Keet
some rights reserved
Uploaded by jan-hendrik jan-hendrik
Source iNaturalist
Associated observations

Photos / Sounds

What

Welwitschia (Welwitschia mirabilis)

Observer

jan-hendrik

Date

July 6, 2014

Description

Baby Welwitschia


There are quite a few observations of this species, but none of them are of seedlings. Thus I have decided to post pictures of one of mine.

This seedling is about 10 months old, sown from seed that I got from Silverhill Seeds.

The remarkable growth is very interesting to observe. I quote here from PlantZAfrica:

"The cotyledons may last for up to two years in cultivation. They become erect and expand to a length of 27-35 mm and the permanent leaves will then become visible between them. They are always opposite to the cotyledons and it is these two leaves that the plant retains for life. The permanent leaves grow rapidly, soon overtaking the cotyledons. They are upright at first, becoming erectly spreading after 8-12 weeks and eventually diverging. Between the two leaves another pair of what appear to be leaves will appear. These are the cotyledonary buds, also situated opposite the cotyledons. They gradually become swollen and keeled and from here onwards, the peculiar growth habit begins. These cotyledonary buds are in fact axillary buds whose apical growth stops, causing the death of the growing tip. Now, instead of apical growth the buds gradually broaden, eventually merging. The meristematic tissue at the base of the buds now grows sideways, together with the meristematic tissue on the outer sides of the leaf, which causes the leaf groove to deepen and causes the characteristic obconical growth of the stem apex. This growth occurs annually during the warmer months and is visible in concentric rings. Thus age can be roughly estimated by counting these rings, analogous to the growth rings of a tree."

I have added labels in the 4th photo to illustrate the above mentioned. You can see how the growing tips of the cotyledonary buds have died.

Fantastic!!!

EDIT: Earlier photos added.

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