categoryZGrasses Grasses List 

SWEET VERNAL-GRASS

Anthoxanthum odoratum

Grasses Family [Poaceae]

month8apr month8april month8may month8jun month8june month8jul month8july

category
category8Grasses
 
 
status
statusZnative
 
 
flower
flower8purple
 
 
flower
flower8yellow
 
 
inner
inner8white
 
 
petals
petalsZ0
 
 
type
typeZspiked
 
 
stem
stem8round
 
 
stem
stem8ribbed
 
 
smell
smell8new-mo
dried
new-mown hay
sex
sexZbisexual
 
 

15th May 2011, Ballykeeroge, Campile, Ireland. Photo: © Paula O'Meara
Grows up to 1m high but usually much shorter at 50cm or so.


26th April 2014, woods, Norton Priory, Runcorn. Photo: © RWD
It is not called 'sweet' or 'odoratum' for nothing; it smells sweet, some say like dried new-mown hay whilst others say of vanilla.


26th April 2014, woods, Norton Priory, Runcorn. Photo: © RWD
The leaf sheaths do not have hairs with glands at their base.


4th May 2019, near Fairy Glen, Appley Bridge, Lancs. Photo: © RWD
The leaf sheaths do not have hairs with glands at their base.


26th April 2014, woods, Norton Priory, Runcorn. Photo: © RWD
The spike before the florets have opened. The spikelets are between 6 to 10mm long.


26th April 2014, woods, Norton Priory, Runcorn. Photo: © RWD
The lowest sheaths are long-pointed at their tip (with a fairly blunt tip).


3rd June 2017, Biggin Dale, Derbyshire. Photo: © RWD
It's genus name is called 'Anthoxanthum' on account of its anthers being yellow coloured - but as the reader can see these are purple! But they are yellow at some earlier stage of their development.

This species is protogynous, which means the long feathery stigma grows out before the anthers, which considerably reduces the probability of self-fertilisation (see the flowers at the bottom).



15th May 2011, Ballykeeroge, Campile, Ireland. Photo: © Paula O'Meara
Each spikelet has two sterile flowers and just one fertile flower which has 2 stamens. The anthers (reddish here) are between 3 to 4.5mm long and here purple(ish) rather than the usual yellow (they probably change colour as they progress). The anthers, which are in pairs, are on long thin white filaments.

The stigmas, which are also in pairs, are white and branch into two.



27th April 2011, Ballykeeroge, Campile, Ireland. Photo: © Paula O'Meara
The stigmas are white and split into two.


4th July 2015, lighthouse, Leasowe, The Wirral. Photo: © RWD
An older specimen.


4th July 2015, lighthouse, Leasowe, The Wirral. Photo: © RWD


4th May 2019, near Fairy Glen, Appley Bridge, Lancs. Photo: © RWD
The stem is mostly hollow inside.


Could be confused with : Annual Vernal-grass (Anthoxanthum aristatum) but that is a faily rare neophyte.

Uniquely identifiable characteristics

Distinguishing Feature : smells sweet and perhaps vanilla-like.

It is said to smell of vanilla (and vanilla smells of vanilla because it possesses VanillAldehyde) aka Vanillin), but the reported aroma-intense compounds present in Sweet Vernal-grass are Hexenal, Heptenal, PhenylAcetaldehyde, 1-Octen-3-one, Methional and other volatiles.


  Anthoxanthum odoratum  ⇐ Global Aspect ⇒ Poaceae  

Distribution
 family8Grasses family8Poaceae
 BSBI maps
genus8Anthoxanthum
Anthoxanthum
(Vernal-Grasses)

SWEET VERNAL-GRASS

Anthoxanthum odoratum

Grasses Family [Poaceae]