Really interesting development in the population dynamics of Ragwort at Silwood. After 4 years of rock-bottom plant numbers (2020, 2021, 2022 and 2023) when the study population looked like this: there are real signs of a come-back in 2024:

This is what Ashurst looks like in a ‘ragwort year’. There are more than 10 flowering individuals per square metre. This is what Ashurst looks like this year (1 August 2023). There’s not a single ragwort plant in sight.

Identifying rushes. The three annual species of Section Tenageia can be tricky to tell apart. The common species is Juncus bufonius (left) and the two rarer species are J. foliosus (upper right) and J. ranarius (lower right).



They all have flat or inrolled bifacial (grass-like) leaves on the stem (the basal leaves are typically withered by flowering time). The diffuse panicle is interspersed with leaf-like bracts and each flower has 2 small bracteoles.

Identifying rushes. The reason why our 31 Juncus spp. are so tricky to identify is that the genus is so complicated botanically. It’s worth starting by looking at each of the 10 Sections that are represented in UK, just so that you can see the issues involved. Section 1: Graminei (J. planifolius, 1 sp.)

Identifying grasses. It’s obviously a Brome, but which Brome is it ? First, we need to identify the genus (i.e. is it Bromus, or Bromopsis, or Anisantha or Ceratochloa ?). This is the lower half of Key H on p. 1033.

#6 Are the lemmas strongly keeled on the back (left) or not (right). Definitely not keeled, so on to #7

Seaside Grass Quiz. This is arranged by habitat (sand-dune, dune slack, rocks & shingle, cliff and tidal mud-flat) then by plant size within habitat (big, medium, small). Answers tomorrow. Sand Dune Big 1.

Grass revision quiz. Waterside and wetland grasses. The are just 10 species in this quiz, reflecting the ecological fact that rushes, sedges and other Cyperaceae are more numerous than grasses in this habitat. Tall 1.

Grass revision quiz. Roadside, railway and waste ground grasses. There is only one properly droopy species in this list (the rest are upright) divided into 3 categories by the height of the flowering stem (tall (>1m), medium (30cm-99cm) and short (less than30cm) ). Answers later. Tall 1.

This is a good time to revise the common grasses, while there is still time to go out and collect any that you have missed. We’ll start with Woodland Grasses, because there have all flowered by now. They are in 5 categories: Tall upright, Tall droopy, Short upright, Short droopy and Acid pine woods. So that you can treat this as a self-assessment quiz, they are numbered, and you can write their names as we go along. You can check out the names at the end of the thread.

Identifying grasses. A tall grass of damp places that's obviously not Phragmites australis or Phalaris arundinacea. We need to look closely at a spikelet. Two things are immediately clear: (1) the inside of the glumes has abundant long, silky hairs, and (2) there is just one floret per spikelet. That means we need to be in Key F (Stace, p. 1030).

Identifying grasses. This is one of the most delicately beautiful of all of the grass-weeds of cereal cultivation. The tall, droopy inflorescence has a delightful metallic-golden sheen. Carefully open up the glumes and look inside. You will see that there is just one perfectly bisexual floret, so we need to be in Key F (Stace, p. 1030). The lemma awn is sub-terminal and the palea is thin and transparent.

Identifying grasses. There are 9 species of Festuca in the “ovina group” and they present a daunting challenge for beginners: F. brevipila, longifolia, glauca, vivipara, filiformis, ovina, lemanii (left), armoricana and huonii (right).

It’s a help that there are a few easy ones that can be dealt with quickly. The commonest proliferating grass that you will find in the uplands is Festuca vivipara. Apart from its proliferating (‘viviparous’) flowers, it’s just like the ubiquitous F. ovina.

Identifying grasses. This is a huge tussock-grass of wet woodland rides (often with Carex pendula) and moist grassland, with beautiful droopy panicles with a silver or golden metallic sheen. Numerous cultivars are used by gardeners in modern herbaceous perennial bedding schemes. Here are its measurement data. Be carful how you handle the plant: its leaf edges are razor-sharp.

Identifying grasses. On the heath, there’s a plant doing an impersonation of Festuca at the moment. It has a dense tussock of blue-grey, hair-like leaves (left) and a pale purple panicle of tiny spikelets, tightly contracted at first, then opening up (right) then closing again. But what genus is it? Let’s begin by finding out what Group it’s in. It is none of the usual suspects (bamboo, maize, etc), it doesn’t have a hairy ligule or ovary, it’s not a Finger Grass or a spike, so we’re down to #12. Here are the measurement data.

Identifying sedges. We’re at the seaside again. Non-droopy female spikes means Key F. We know enough already to skip quickly over Carex pallescens, flacca, riparia, rostrata, vesicaria and acutiformis, and start in earnest at #9 because the lowest bract is sheathing (right). #9 The stems are densely tufted, so on to #14

Identifying grasses. This is a sub-dominant grassland plant (as was Koeleria macrantha last week) that makes up a minor part of the total grass biomass but persists nonetheless. The flower-head has a delightful golden sheen. It has a bent awn from the middle of the back of the lemma, so the genus will key out in Group I. Here are its measurement data:

Identifying sedges. We are in damp brackish grassland above the mud flats of the estuary. Our plant is a rather nondescript member of subgenus Vignea (all spikes look alike, no separate male and female spikes), so it's in Group B. It has 2 stigmas so we can start at #6 #6 It consists of spaced-out shoots from a creeping rhizome (i.e. not densely tufted) so on to #7.

Identifying grasses. Twenty years ago this was a rarity. Now it is one of the commonest pavement plants in towns from London to Edinburgh. It has tiny individual spikelets held in whorls (one of it’s old names was verticillata), so it’s highly distinctive. But what is it? First, we need to find what Group it is in. Here are its measurement data. ‘Scaberulous’ means “somewhat scabrous”. I know what you’re thinking. ‘Scabrous’ means “rough with minute points or knobs” (as distinguished from a general unevenness of the surface).

Identifying grasses. Crested Hair-grass (Koeleria macrantha) is one of those rather nondescript grasses that one feels one ought to know, but doesn’t. It's commonest on chalk and limestone and at the coast but also grows on nutrient-poor sands where competition is less intense. Let’s begin by finding out what Group it’s in. It is none of the usual suspects (bamboo, maize, etc), it doesn’t have a hairy ligule or ovary, it’s not a Finger Grass or a spike, so we’re down to #12. Here are the measurement data.

Identifying sedges. Two species from the Berkshire side of the Blackwater River in Camberley: Carex elongata (left) and C. disticha (right). The multiple spikes are all alike, so both species are in Key B. We’ll do Carex elongata first. Key B is on Stace p. 1000. #1 Stigmas 3 (left) or stigmas 2 (right). There are 2 stigmas, so on to #6

Identifying grasses. This huge seaside plant with pale blue-grey leaves is unmistakable, so it’s an ideal candidate for learning about genera with inflorescences in the form of a spike (Key D). All the spikelets are bisexual and similar. It is often found on the seaward side of Marram grass dunes or at the top of a shingle beach.

Here are the measurement data from our plant