categoryZGrasses Grasses List 

REED SWEET-GRASS

Glyceria maxima

Grasses Family [Poaceae]

month8jun month8june month8jul month8july month8aug

category
category8Grasses
 
status
statusZnative
 
flower
flower8green
 
petals
petalsZ0
 
type
typeZspiked
 
stem
stem8round
 
smell
smell8sweet
sweet
sex
sexZbisexual
 

11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD
An erect plant growing in or beside water up to 2.5m high (normally 60 to 200cm). It forms less expansive groups than do those of Common Reed which also grows in water , marshes, swamps, fens and damp clayey slopes.


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD
The infloresces at the top are erect, densely flowered, and with many branches. The panicles spread and are between 15 to 30cm long.


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD
The spikelets ar 5 to 8mm long, narrow-oval in cross-section (not cylindrical!), furrowed, and both of the glumes are pointed. The anthers, when fresh, are yellowish-green and 1mm long, and may be visible as short, narrow, now-brown objects poking out of the top of two flowers about 2/3rds way down this photo.


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD
The lemmas (being the outermost of 2 bracts enclosing the flower immediately above where the green stem ends) are 3mm long, oval, and without teeth. They are blunt and rough to the touch.


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD


11th Aug 2018, L&L canal, Maghull, Merseyside Photo: © RWD
Unusually for a grass-type plant its leaves are bright-green, often flat or more or less folded. They are up to 2cm wide and are smooth to the touch and taper to their pointed tips. The edges are thickened and minutely toothed. The sheaths of the leaves are, however, rough and with a brown band at the top about 5mm long.


Not to be semantically confused with : Sweet Vernal Grass (Anthoxanthum odoratum) Small Sweet-grass (Glyceria declinata), Floating Sweet-grass (Glyceria fluitans), Plicate Sweet-grass (Glyceria notata), Small Sweet-grass (Glyceria declinata), Sweet-Nancy (Achillea ageratum), Sweet-flag (Acorus calamus), Slender Sweet Flag (Acorus gramineus), Sweet Pepper (Capsicum annuum), Sweet Chestnut (Castanea sativa), Sweet William (Dianthus barbatus), Sweet Spurge (Euphorbia dulcis), Meadowsweet (Filipendula ulmaria), Sweet-potato (Ipomoea batatas), Sweet Pea (Lathyrus odoratus), Sweet Alison (Lobularia maritima), Sweet Clover (Melilotus messanensis), Sweet Cicely (Myrrhis odorata), Sweet Tobacco (Nicotiana alata), Sweet Box (Sarcococca hookeriana), Sweet Scabious (Scabiosa atropurpurea), Sweet-William Catchfly (Silene armeria), Bittersweet (Solanum dulcamara) nor with Sweet Violet (Viola odorata) [plants with similar names belonging to differing families]

Some similarities to : Common Reed (Phragmites australis) which grows taller, up to 3.5m and occupies the edges of canals and other wet places but has a reddish-purple inflorescence (not green like Reed Sweet-grass). There is also Reed Canary-grass (Phalaris arundinacea), another plant which likes to grow beside water or in damp places, and that grows to a similar 2m height of Reed Sweet-grass but has a green to reddish-brown tinged inflorescence.

It derives the 'sweet' part of the common name from the fact that it smells sweet which is due to the presence of the benzopyran Coumarin, which smells of freshly mown hay. Coumarin is used as a perfume.

It also contains toxic levels of Cyanogenic Glycosides which can cause poisoning of livestock unaccustomed to its presence.


  Glyceria maxima  ⇐ Global Aspect ⇒ Poaceae  

Distribution
 family8Grasses family8Poaceae
 BSBI maps
genus8Glyceria
Glyceria
(Sweet-Grasses)

REED SWEET-GRASS

Glyceria maxima

Grasses Family [Poaceae]