Marsilea - Marsileaceae

Marsilea distorta A. Braun

 

 

 

 

Synonyms

Common name

Description

Rhizome slender, wiry, repeatedly branched, glabrous except for the usually villous nodes; internodes 0.5–5 cm long. Stipe up to 10(-15) cm long, wiry, usually hairless. Leaflets grass-green to olive-green, obtriangular to obdeltate in outline, slightly asymmetrical, 6-11(-15) × 4-8(-11) mm, outer margins rounded to almost straight, irregularly crenate-dentate, long pellucid streaks between the veins (the edges of these streaks appear prominent as parallel ridges on the lower surface of the leaflets), scatterly set with long soft hairs to almost hairless. Sporocarps: crowded, in clusters at the base of the stipe, brown, 3.5-4.5 mm long, 2.75-3.25 mm high, 1.8-2.5 mm thick, not bordered, broadly elliptic to oblong-elliptic in lateral view, vertical cross-section elliptic, densely covered with brown hairs; lateral ribs 6–12, visible to a varying degree, rarely invisible; veins (as seen on the interior surface) not anastomosing; raphe distinct, prominent, but very short, only attached to 1/5–1/3 the length of the base of the sporocarp; lower tooth prominent appearing as a recurved apex of the raphe, upper tooth absent or present as a dark circular spot. Pedicels 4-12(-14) mm long, free, twisted, pigtail-like curved and often encircling the entire sporocarp, flexuose, usually growing downwards and thus burying the sporocarps in the ground, several arising from the base of the stipe. Sori (8–)10–14.

Notes

It differs from other species in having translucent streaks between the veins in the leaflets, the sporocarp is lacking a superior tooth and has a stalk that is conspicuously curved and twisted.

Derivation

distorta: deformed or twisted, referring to the pigtail-like curved pedicels of the sporocarps.

Habitat

Seasonally flooded areas, swamp and lake shores.

Distribution worldwide

See African distribution.

Distribution in Africa

Botswana, Burkina Fasso, Liberia, Mali, Mauritania, Mozambique, Namibia, Senegal, Sudan and South Sudan, Tanzania , Zambia, Zimbabwe.

Growth form

Terrestrial.

Literature

  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Page 68. (Includes a picture).
  • Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature. Pages 232 - 233. (Includes a picture).
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 476 - 477. (Includes a picture).
  • Launert, E. (2003) Marsileaceae. Flora of Tropical East Africa, Pages 6 - 7. (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. Page 56.
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta. Southern African Botanical Diversity Network Report, 13 Page 175.
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