6
The situation is not helped by name changes (see synonyms overleaf). Agrostis merges into
Calamagrostis and Tom says probably ought to be lumped with it. A. castellana for example,
has a (minutely) hairy lemma callus (to 0.3mm long) which is a character of Calamagrostis.
Unless you are happy with sorting them out, can we just make sure that we have them
accurately recorded for each 10km square, and then for each lxl km square, if you have not
sorted them out simply pat Agrostis aggregate on the back of the card.
The following is a summary of the Agrostis species we are likely to encounter in Essex. A key
to the more exotic ones is to be found in 'Alien Grasses' BSBI 1996. By Ryves, Clement and
Foster.
1 Plants with VESTIGIAL palea, & ligule of FLOWERING stems ACUTE, awn 0
or from BASE of lemma, panicle open or closed after anthesis.
The A. canina complex:
A. canina - wet grassland, flowers early, NEVER any rhizomes, but occasionally
has stolons.
A. vinealis (montana) - dry grassland, flowers late, rhizomes PRESENT, but
NEVER any stolons.
Plants with WELL DEVELOPED palea, ligule of FLOWERING stems TRUNCATE:
Panicle OPEN after anthesis:
A. capillaris (-tenuis) - ligule of STERILE shoots WIDER than
LONG, rhizomes AND stolons present,
awn 0 or arising ON BACK OF LEMMA.
Panicle branches smooth or only thinly
scabrid.
A. gigantea - ligule of STERILE shoots LONGER than
BROAD, rhizomes present but NEVER
stolons, awn 0 or SUBAPICAL. Panicle
branches scabrid.
Panicle CLOSED after anthesis:
A. stolonifera -
stolons present but NEVER HAS rhizomes,
awn 0 or SUBAPICAL, not exceeding the
glumes, primary panicle branches bearing
spikelets to the base, lemma with glabrous
callous.
A. castellana -
rhizomes present but NO stolons, awn 0 or
from base of lemma, primary panicle branches
naked below, lemma with shortly bearded
(0.3mm) callus.
Essex Field Club Newsletter No. 19, November 1996