Eleocharis acicularis

Needle Spike-rush

IMG_5254
Flowmead Country Park, Kent, May (Sue Buckingham)

Overview

  • a very slight and slender plant with thread-like stems
  • patch-forming
  • often shy-flowering
  • spikelets tiny, short, and few-flowered
  • lowest glume encloses base of spikelet, and a quarter to a half as long as spikelet
  • stigma 3-forked (as in multicaulis and parvula; contrast uniglumis and larger species, 2-forked)
  • ripe nut has horizontal and vertical ridges, unique in the genus; style-base tiny
  • grows in shallow water, or exposed, on silt/sand in +/- still water, often submerged, mainly lowland (contrast parvula: very local, estuary mud only)

Growth

~ makes open or sometimes dense patches
~ can make extensive submerged sheets in sheltered stretches of lowland rivers, but will only flower in dry seasons when exposed

Stems

~ up to 15 cm but often much shorter
~ only to 0.3 mm wide, narrower than the squatter plant
parvula

IMG_8416 small 2
Kent, May (specimens from Sue Buckingham)

Eleocharis acicularis 7866 sm (1 of 1) (1)
Dorset, early September (photo Robin Walls; herb. specimen)

Focus Result (A, 8, 4) crop 2
stem section

IMG_8424 small
epidermal peel, showing two files of stomata

IMG_8428 small
epidermal peel (closer); two stomata


Spikelets
~ short, few-flowered
~ lowest glume about quarter to half as long as the spikelet, and encloses its base
~ glumes darker and richer brown than in
parvula

El.acicularis 01
Kent, May (Sue Buckingham)

IMG_8421 small 2
Kent, May (specimen from Sue Buckingham)

Flowers
~ stigma 3-forked
~ perianth bristles often none, short if present

Nuts
~ style-base (stylopodium) is tiny; not swollen
~ style-base with tiny constriction

Habitat
~ grows in shallow water, or exposed, on silt/sand in +/- still water, often submerged, mainly lowland (contrast
parvula: very local, estuary mud only)

IMG_5268
Spreading green carpets, Flowmead Country Park, Kent, May (Sue Buckingham)

Eleocharis acic Hatchet Aug 1984 sm
With Pilularia, Hatchet Pond, Hampshire, August (Roger Smith)



Frequency & range
~ scattered throughout.
See distribution map.

Links to the other Eleocharis spike-rush pages (also accessible from the sidebar)