Eleocharis ~ separation of confusion pairs:

uniglumis versus quinqueflora


Shared features

  • uniglumis can be slender enough to look superficially similar to quinqueflora
  • the basal glume surrounds the base of the spikelet
  • can grow together rarely in upland calcareous mires

Separation

Readily separated on these characters:

~
length of basal glume versus length of spikelet:
          
uniglumis has the basal glume less than 1/5th the length of the spikelet
          
quinqueflora has the basal glume often about 1/2 the length of the spikelet, or even more.

(Beware some
quinqueflora spikelets with a lowest glume shorter than half spikelet length, suggesting uniglumis. See below: in immature plants check stigmas (quinqueflora 3-forked; uniglumis 2-forked), and if mature, check nuts (quinqueflora: slender style-base and no 'neck'; uniglumis: obvious 'neck' below swollen style-base).)


quinqueflora (early season, flowering) showing basal glumes
encircling spikelet base, and half as long as spikelet


uniglumis, showing basal glumes much less than half as long as spikelet


~ numbers of flowers in spikelet (count glumes; nuts could be counted, but be aware some flowers fail to ripen nuts):
          
uniglumis has normally10 or more flowers
          
quinqueflora has 7 or fewer

~
stigma forking:
          
uniglumis 2-forked
          
quinqueflora 3-forked

~ style-base shape (when nuts ripening) is very distinct:
          
uniglumis has style-base very much swollen, with distinct ‘neck’ (below left)
          
quinqueflora has style-base confluent with nut (below right)

         uniglumis        ripe nuts            quinqueflora



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