Monday, 30 May 2011

Helictotrichon pubescens - Downy Oat-grass

Grass of the Month for May 2011                

Downy Oat-grass is one of my favourite grasses

  • It flowers early in the year, in early May - two weeks before its relative, Meadow Oat-grass
  • It has big shiny spikelets
  • It is easy to identify vegetatively because it is one of only two "ordinary" medium/large grasses which have newest leaf folded and have hairy leaves.
  • The other grass is Bromopsis erecta - but Bromopsis has long tapering points to the blades, whereas Helictotrichon has parallel sided blades with blunt, hooded (boat shaped) tips
  • Its leaves feel soft and downy
  • The base of the blade is as wider or wider than the middle of the blade
  • It grows on base rich soils so can be found with other interesting plants
  • the vegetative shoots can have red stripes on their shoots a little like Holcus - but Helictotrichon has folded leaves.

The other "ordinary grass" with folded leaves is Upright brome - Bromopsis erecta. Helictotrichon has very blunt  leaf tips - shown here - whereas Bromopsis has very gently tapering leaves.

Helictotrichon vegetative leaves have short ligule (shown at top) -but the culm leaves have longer ligules as you go up the stem.

Helictotrichon pubescens has two or three florets per spikelet, hence two or three awns per spikelet.
Helictotrochon pratense has three to six florets per spikelet.  This is very helpful except when you find a plant with three florets per spikelet.

(for links to other grasses through 2010 and 2011 see Grasses Page)

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