Eleocharis uniglumis

Slender Spike-rush

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Stacks Image 370

Eleocharis uniglumis, inland form, Tarn Sike (Cumbria), July 2011

  • variable, often rather slender plant, creeping, and can make extensive, although generally rather open, patches
  • narrow and often quite pointed spikelet
  • lowest glume encloses base of spikelet (like multicaulis and quinqueflora, but not elongated as in quinqueflora)
  • ripe nut with style-base strongly swollen (much like palustris)
  • largely coastal in saltmarshes, etc.; much sparser inland, mires of various types, normally with some mineral influence

Growth & size

~ stems very variable in height; often 15-30 cm but can be up to 50 cm or more in height, often rather dark green and shiny; red/purple-based or not
~ stems typically narrower than the ‘big two’ species (i.e.
austriaca and palustris): 0.8-1.5 mm across, circular in section
~ sheath apex +/- transversely truncate
~ growth: patch-forming, but small tufts develop at the nodes of the creeping rhizomes

typical red-based stems (scale is 5 cm)

sheath-apex transversely truncate

~ mostly slender and cigar-shaped, can be more oval-lanceolate, sometimes asymmetric
lowest glume +/- fully encloses spikelet, mostly less than a fifth the length of the spikelet.


~ stigma 2-forked (as in austriaca and palustris)
~ perianth bristles variable in both number and size
usually shorter than nut

~ style-base (stylopodium) is swollen, broad, and with a clear ‘neck’ a constriction at its junction with the nut (much like palustris or even larger in proportion to the nut)

ripe nuts

Stem section
~ much as palustris, although layers of green tissue less deep and approaching austriaca. (Section was made from dried material, hence rather ‘colourless’; damaged in part, but clear enough.) Close-up shows abundant fibre-bundles.

stem section

stem section closer: abundant fibre-bundles (pentagonal structures around periphery)

~ most close to palustris, with abundant fibre-bundles, and narrow sections of ‘ordinary’ cells, with the rows carrying stomata mostly three cells wide. (See page ID:palustris/austriaca for wider discussion of epidermal peels. Includes technique to obtain peels.)

epidermal peel

~ saltmarshes in pools and in turf and other coastal habitats
~ much less frequent inland in lowland fens, and in upland mires, especially where spring-fed and with at least a modicum of base.

Tarn Sike (Cumbria): inland site of uniglumis;
with quinqueflora in open calcareous seepages by outlet stream from Sunbiggin Tarn

Frequency & range
~ scattered throughout; rather more frequent in the west and north. See distribution map

The putative hybrid between palustris and uniglumis is dealt with on the hybrid page.

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