categoryZGrasses Grasses List 

SALTMARSH FLAT-SEDGE

Blysmus rufus

Sedge Club- & Spike-Rush Family [Cyperaceae]

month8aug month8sep month8sept

category
category8Grasses
status
statusZnative
flower
flower8brown
petals
petalsZ0
type
typeZspiked
stem
stem8round
stem
stem8ribbed
rarity
rarityZuncommon
sex
sexZbisexual

30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD
A medium to low plant growing to 45cm high with greyish green stems. [The greener leaves from bottom right to the middle are probably of some interloping grass as the real leaves of Flat Sedge are a similar dull green with browny stripes in places]


30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD
The inflorescence at the top is a short flattened spike with between 5 to 8 spikelets per spike.


30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD


30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD
The spikelets (of which there are 8 in this specimen) are arranged alternately slightly higher and opposite to each other, (and not all around the top as most spikelets are arranged on other Sedges). Each spikelet can contain between 3 to 5 flowers.


30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD
The lowest sheaths on each spikelet are called glumes, which are blackish-brown and 5mm long and blunt at the top.


30th June 2018, West Kirby, Wallasey, Merseyside. Photo: © RWD
The green basal bract at the bottom of the spike does not usually overtop the spike (it usually being well short) - (unlike the otherwise fairly similar Flat-Sedge (Blysmus compressus) on which the basal bract overtops the spike).


Easily mistaken for the very similar Flat-Sedge (Blysmus compressus): [see caption on last photo]

Not to be semantically confused with : Flat-spine Burr-ragweed (Ambrosia acanthicarpa), Dense Flat-sedge (Cyperus congestus), Flat-stalked Pondweed (Potamogeton friesii) nor with Flattened Meadow-grass (Poa compressa).

Easily distinguished from other Sedges by the spike of flowers which are alternately on opposite sides of the stem in a flat configuration - hence the name 'Flat Sedges' - of which there are only 2, this one and Flat-Sedge (Blysmus compressus).

Uniquely identifiable characteristics

Distinguishing Feature : see above

It grows in saltmarshes and on turfy dune-slacks on the coasts of of Britain and Ireland but apparently not further south than North Lincolnshire or Glamorgan (last time anyone looked)...


  Blysmus rufus  ⇐ Global Aspect ⇒ Cyperaceae  

Distribution
 family8Sedge Club- & Spike-Rush family8Cyperaceae
 BSBI maps
genus8Blysmus
Blysmus
(Flat-Sedges)

SALTMARSH FLAT-SEDGE

Blysmus rufus

Sedge Club- & Spike-Rush Family [Cyperaceae]