Isoetes - Isoetaceae

Isoetes wormaldii Sim

Photo: JE. Burrows
South Africa

Photo: JE. Burrows
South Africa

 

 

 

 

Synonyms

Common name

Description

Pseudo-corm 3-lobed; bud scales absent. Leaves 30-70, flaccid, floating when mature, oval to flattened in transverse section, terminating abruptly in a rounded apex, 150-470 x 2-3 mm, base flaring to a 3 mm wide wing on either side of sporangia. Ligule narrowly triangular, 2.5-3.0 mm long, dark brown. Velum absent or very narrow, up to 1 mm wide. Sporangia ovate-triangular, 2.0-2.5 x 3.0-4.5 mm. Megaspores ± 0.6 mm in diameter, white, reticulate, the reticulations enclosing deep cavities with raised 'knobs' present at many of the junctions of the reticulations, proximal surface similar to the distal surface.

Notes

Derivation

wormaldii: this species was first found by Mr. W.H. Wormald in Queen's Park, East London in 1893.

Habitat

Temporary pools and streams or as a perennially submerged in slow-flowing rivers, rooting in mud below water level.

Distribution worldwide

See African distribution.

Distribution in Africa

South Africa.

Growth form

Terrestrial.

Literature

  • Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature. Pages 74 - 75. (Includes a picture).
  • Roux, J.P. (2009) Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23, South African National Biodiversity Institute, Pretoria. Pages 11 - 12.
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