Groovy ‘living fossil’

The strobili

The strobili

When you walk in the veld you can easily overlook Equisetum ramosissimum subsp. ramosissimum also known as horsetail or scouring rushes because they look so much like grass. Although not rare, this is the only species of Equisetum in southern Africa. The name Equisetum derives from the Latin word equus (a horse) and seta (a bristle) and these are a primitive subclass of ferns. Members of this family are relics and much reduced compared to the Late Triassic (245 million years ago) when they were more diverse and common.

 

Horsetail stems and strobili

Horsetail stems and strobili

They have a peculiar bristly appearance and do not look like anything one would normally associate with a fern. The stems are hollow, erect and brittle with a rough feel to it. At the nodes in the stem are tiny scale-like leaves. The spores are borne in cone-like structures, strobili, at the tip of some of the stems. When you touch or lightly shake the strobili, spores are released in a grey mist. The creeping rootstock makes it nearly impossible to dig out. And to top it all, some species deposit so much silica in their stems that bunches of them have been used for polishing metal.
They are very adaptable but prefer wet soils and can be seen at many stream crossings in Mountainlands.

Suggested reading: Crouch, N.R; Klopper R.R; Burrows, J.E and Burrows, S.M. 2011 Ferns of Southern Africa A Comperehensive Guide. Struik Nature, Cape Town.

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