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Mick Crawley

@crawley_mick

6 Jul

Here are the answers to the grass quiz. Don't worry about not knowing species in habitats you don't visit. I suggest you visit each of your local habitats in turn and make a point of finding, pressing and closely observing the species you didn't get right. Let me know your score.

roadside
1) Arrhenatherum elatius
2) Dactylis glomerata
3) Poa trivialis
4) Festuca arundinacea

waterside
1) Phragmites australis
2) Phalaris arundinacea
3) Glyceria maxima
4) Alopecurus geniculatus

Read 13 tweets

Mick Crawley

@crawley_mick

20 Jun

Key to the common species of Agrostis. You should collect underground parts and dissect a spikelet before beginning the key to determine whether the palea is large or small (more or less than 2/5 of lemma length). We shall start with the species with larger paleas.

Select a spikelet from the very top of the inflorescence. If the back of the lemma is hairy (left) and there is a sticking-out awn, you have Agrostis castellana (much planted in commercial grass seed). Hairless (right) is something else.

Look at the ligule on the upper-most culm leaf. If it is small (0.5-1.5mm) you have the widespread and abundant Agrostis capillaris. Larger ligules (2-6mm) are something else.

Read 7 tweets

Mick Crawley

@crawley_mick

20 Jun

Genera of Poaceae. Agrostis. When you see a grass with a big open panicle like this (left) with tiny spikelets that look as if they might contain just 1 floret (right), your mind should turn to the genus Agrostis.

Agrostis is fiddly because the flowers are so small and tricky because it is essential that you bring back the underground parts from the field. You need to dissect the spikelt and expose the lamma and, crucially, the palea

Then, with some carefully cleaned underground parts, you need to say whether the plant has rhizomes (left) or stolons (right).

Read 7 tweets

Mick Crawley

@crawley_mick

20 Jun

Here is one of my candidates for ‘most elegant of all British grasses’. It’s Apera spica-venti, and has a droopy, shining golden inflorescence, made up of tiny spikelets with ridiculously long awns.

It stands about 1m tall, and its considerable height means that the individual spikelets (less than 3mm long) look even smaller than they are. The awns can be up to 4 times this length (they are as much as10mm long and are seldom less than 5mm).

Apera is one of the genera where there is just 1 floret per spikelet, hidden completely by the glumes (Key F in Stace, with companions like Agrostis and Polypogon)

Read 6 tweets

Mick Crawley

@crawley_mick

19 Jun

Before we embark on the (admittedly daunting) key to the species of Festuca, it’s a good idea for you to get a thoroughly good idea of what a fescue looks like. The most sensible species to use is Festuca rubra: it’s in flower now, it’s very abundant, and it’s easy to identify.

Go out into your nearest grassland and ignore the conspicuous Holcus lanatus, Dactylis and Arrhenatherum. Look at ground level for the grass with the narrowest, most hair-like, bright green leaves. Pull up a handful big enough to guarantee having a flowering stem in it.

Shake off all the other grasses and you should be left with a flowering individual of Festuca rubra (left). It is a good idea to check that it’s not Deschampsia flexuosa (it should have straight, not wavy (right), panicle branches).

Read 11 tweets

Mick Crawley

@crawley_mick

18 Jun

So how do you tell Phalaris (left) from Phleum (top right) from Alopecurus (bottom right) ?

These 3 foxtail grass look-alikes are easy to separate as long as you use your x10 on the outrside of the flower head. If it has got awns, it's Alopecurus.

If the glumes have two horns it's Phleum

Read 5 tweets

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