<i>Briza media</i> L.

A loosely tufted perennial with short rhizomes from which arise vegetative shoots. Culms 15–60 (−100) cm high, slender, erect, 2–3-noded, solitary, smooth. Leaves with dull glaucous to mid-green adaxial and abaxial surfaces, hairless; blades usually 4–20 (−28) cm long, 2–4 (−7) mm wide, with minute acroscopic teeth on the margins, with a slender boat-shaped tip; ribs numerous, closely packed, less obvious on the abaxial surface; sheaths smooth, entire, soon splitting, dark reddish-brown at base; ligules up to 1.5 mm long, membranous, blunt with irregular margins. Culm leaves 3 or 4, uppermost with long sheaths. Panicles 4–10 (−18) cm long, lax, roughly pyramidal, with up to 20 branches, and up to 60 spikelets, sparsely divided, spreading, with scabrous hair-like pedicels 5–20 (−50) mm long and slightly thickened below the spikelets. Spikelets 4–7 mm long and wide, loosely scattered and drooping, broadly elliptic to broadly ovate, laterally compressed, generally purplish-brown, usually breaking up at maturity beneath the lemmas but many spikelets remaining undispersed on the branches and shed from the panicle intact, 4–9 (−12)-flowered. Glumes slightly unequal, deeply concave, hooded at the apex, boat-shaped, 2.5–3.5 mm long, with 3–5 veins, firmly membranous, dull-purple with white and shiny margins. Lemmas 3.7–4.1 mm, strongly cordate at the base, bluntly keeled in the lower half, closely overlapping, rounded on the back, with 7–9 veins, variegated purple and green, with hyaline margin. Paleas flat, thin, almost as long as the lemma, with two keels, narrowly winged. Lodicules 2, linear-lanceolate, acute. Grain enclosed within the papery lemma and palea, c. 2 mm long, rounded on the back, flattened on the front; mean oven-dry weight 0.53 mg. The root system is a dense mat of whitish fibrous roots. The primary roots are up to 1 mm in diameter and are largely unbranched, but there is a dense network of branching secondary roots. The root mass is fairly vertical with an average root length of c. 40 cm. The species produces pale brown rhizomes up to 13 cm long and 1.5 mm in diameter. Native. Subspecies media occurs throughout the range; subspecies elatior (Sibth. & Sm.) Rohlena occurs in south-east Europe. Briza media is a widely distributed common species of dry and calcareous, but also moist and acidic grassland, of little herbage value. The distribution of B. media in the British Isles is shown in Fig. 1. The species is widely distributed throughout the British Isles on Chalk, Carboniferous, Magnesian and Devonian Limestone, and is also found on circumneutral soils and on some acid soils where these are well-drained. The species is only occasional in the north of Scotland, the Shetland Isles and Orkney Isles and on some of the Western Isles. It has been recorded from the Isle of Man, the Channel Isles and the Isle of Wight but not from the Isles of Scilly. In Wales the species is common on the Lias of South Dyfed and on the calcareous substrata in the south of Powys but occurs less frequently on calcareous substrata of Gwent, Gwynedd and Clwyd (Hyde & Wade 1957). It is widely distributed across central Ireland, but is less common in both the north and the south of Ireland. The distribution of Briza media in the British Islea. (○) Pre-1950; (•) 1950 onwards. Each dot represents at least one record in a 10-km square of the National Grid. Mapped by Henry Arnold, Biological Records Centre, Centre for Ecology and Hydrology, using Alan Morton's DMAP programme, mainly from records made by members of the Botanical Society of the British Isles. Briza media is recorded throughout western Europe but is absent from the Faeroe Islands and Iceland, and is noted only as a casual in the extreme north of Europe in Flora Europaea. It is absent from the Mediterranean islands of the Balearics, Crete, Sicily and Cyprus, and does not occur in the Azores. In northern Europe, B. media is found in the Baltic, Karelia (southern part), Ladoga-Ilmen, Dvina-Pechora (western and southern parts), Upper and Middle Dniepr, the Upper Volga, Volga-Kama, Volga-Done (northern part), Ural (central and southern), Carpathians and the Caucasus (Tsvelev 1984). Dahl (1998) refers B. media to a southern boreal sub-element, and Preston & Hill (1997) assign it to the European temperate floristic element. Outside Europe, B. media has been recorded from Syria and Turkey, and from Kashmir, Myanmar, Nepal and Tibet. The species is also recorded from South Africa, and from Australia and New Zealand (Vergl. Chor.) as an alien. In North America, the species is introduced and occurs in Connecticut, Massachusetts, Michigan and Vermont in the United States and in British Columbia and Ontario in Canada (Hitchcock 1971). Briza media is found to 65° N in Europe (Sweden), to c. 30° N in Asia and to c. 50° N in North America. In England, B. media has an altitudinal range from sea-level to 640 m (Cumbria), from sea-level to 515 m in Wales (Tal-y-Fan), from sea-level to 655 m in Scotland (Atholl) and from sea-level to 427 m in Ireland (Wicklow) (Alt. Range Br. Pl.). It is found to 1870 m in the Alps (Pfl. Exk.), to 3000 m in the Caucasus, to 1000 m in the Carpathians, to 1450 m in the Pyrenees, to 3500 m in Nepal and to 4500 m in the north-west Himalayas. Briza media is exposed to annual precipitation of around 1700 mm on the Isle of Mull and to conditions with less than 1 mm precipitation during July and August in southern Spain, where average monthly maximum temperatures are around 43 °C (Meteorological Office 1972). It experiences temperatures as low as −35 °C in January in Estonia; however, the effects of these low temperatures are moderated by an insulating blanket of up to 20 cm of snow, which normally persists from November to the beginning of April (Lippmaa 1931). No evidence in Britain of wind or insolation damage has been noted, and the species is found on steep dry slopes in the Jura Alps subject to strong insolation, and to Föhn-swept slopes in Germany (Braun-Blanquet 1939). Briza media is found both on flat ground and on slopes up to about 60°, but is most common on slopes between 20 and 40° (Grime et al. 1988). The species shows no aspect preference in the British Isles nor in western and central Europe. Briza media is a component of semi-natural calcareous pastures, scree slopes, quarry spoil and road verges, and has been recorded from old meadows and enclosed pastures (Grime et al. 1988). It is widespread on brown earths, shallow free-draining rendzinas and grey rendzinas overlying chalk and limestone in England, but is less frequent on these in Wales and northern Scotland. Grubb et al. (1969) recorded B. media from tall chalk heath at Lullington Heath, Sussex, and Ivimey-Cook & Proctor (1966) recorded it from limestone heath in the Burren, Co. Clare. The species has also been recorded from wet heathy roadsides and from water meadows on rich soils (Edees 1972), from limestone swamps (Horwood & Noel 1933), grazed fen flushes (Sinker et al. 1985) and from calcareous mires (Grime et al. 1988). It is also recorded from calcareous peats and from clays with impeded drainage (Sinker et al. 1985), from Keuper marls and Carboniferous shales (Newton 1971), from Coal Measures (Graham 1988), from Liassic clays and marls, from Bunter sandstone, from incipient podsols (Balme 1953), from neutral to acidic grassland and heaths (Grose 1957) and from the very acid sands of the Weald, with pH < 4.0 (C. Stace, personal communication). It is recorded from volcanic rocks and stabilized sand dunes in Wales (Benoit & Richards 1961), from coastal sands in Yorkshire (Crackles 1990), and from dry dune pasture at Braunton Burrows, north Devon (Willis et al. 1959). Briza media occurs on brown forest soils, on high base status humic gleys, peaty gleys and flushed peat in Scotland (Gauld & Robertson 1985) and also from raw soils on sandy river shingle (Birse 1980). Briza media is recorded as occurring in soils of between pH 4.0 and 8.0 but most frequently in soils of around pH 7.0 (Ecol. Atl.). Soil analyses (methods according to Chem. Anal.) for 15 British sites supporting B. media gave a range of exchangeable calcium and magnesium, extracted with M ammonium acetate (pH 9.0), from 1200 to 7500 mg kg−1 and from 30 to 500 mg kg−1, respectively, while potassium ranged from 30 to 540 mg kg−1. Phosphate phosphorus, extracted with 0.5 m sodium bicarbonate (pH 8.5), ranged from 5 to 39 mg kg−1 and total nitrogen from 0.1 to 1.9%. In Continental Europe, in addition to soils overlying calcareous rocks, B. media occurs on calcareous moraines (Sterner 1922), on dry shell deposits (Willems 1982), on slate (Andersson 1970) in southern Sweden, on porphyr and gypsum (Meusel 1940), on dry acid soils (Ellenberg 1988) in Germany, and from biotite and granite gneiss in Switzerland (Marschall 1947). While B. media may be considered as most typically a plant of fairly dry, well-drained calcareous soils, it has a very wide edaphic tolerance, growing successfully in distinctly acidic soils, wet and poorly drained sites and on soils of many different textures. Briza media is predominantly a species of calcareous grasslands and occurs with a high constancy in the following communities defined by the National Vegetation Classification (Rodwell 1991, 1992). CG1 Festuca ovina–Carlina vulgaris grassland is found on freely (often excessively) draining rendzina soils with a high base status, on steep and rocky, but stable, slopes on hard limestones, usually with a southerly to westerly aspect and so with a tendency to summer droughting. Often heavily grazed by sheep and rabbits, this community is confined to Devonian Limestone in Devon and to Carboniferous Limestone in Wales and the Mendips. Briza media has an overall constancy of III in CG1 but attains a constancy of IV in the subcommunities of Helianthemum canum and Trinia glauca and a constancy of V in the Koeleria macrantha subcommunity. Constant species, as defined by the NVC, for CG1 and the following communities are given in Table 1. CG2 Festuca ovina–Avenula pratensis grassland consists of a rich mixture of grasses and dicotyledons in a closed sward and is traditionally grazed by sheep and rabbits. It occurs most frequently in relatively dry and warm, lowland climates on free-draining calcareous soils derived from calcareous bedrock, often prone to summer droughting. Briza media has a constancy of IV in this community. CG3 Bromus erectus grassland achieves maximum extent on lightly grazed or ungrazed grasslands over Chalk in the south-eastern areas of Britain, and over the Oolite of the Cotswolds and Northhamptonshire. Briza media has an overall constancy of III in this community, but a constancy of IV in the subcommunities of Centaurea nigra and Knautia arvensis–Bellis perennis. CG4 Brachypodium pinnatum grassland is also mainly associated with lightly or ungrazed calcareous swards in south-eastern Britain, but is more generally found on the cooler and damper areas of the Chalk and Oolite than is the Bromus erectus grassland, which is more continental in character. Briza media has an overall constancy of III in this community. CG5 Bromus erectus–Brachypodium pinnatum grassland occurs where B. pinnatum is favoured by amelioration of extreme Continental conditions, but not so greatly as to exclude Bromus erectus. The community is most characteristic on the calcareous, base-rich soils of the Oolite on the north-western fringe of lowland limestones of the Cotswolds and Northhamptonshire/Lincolnshire scarps. Briza media has an overall constancy of IV and of V in the Hieracium spp. subcommunity. CG6 Avenula pubescens grasslands are found on a variety of gently sloping lowland limestones, mainly in the south of England. The soils are deep and moist, though mostly free-draining alluvial rendzinas, or calcareous brown earths, and in some cases more mesophytic soils occur on flat limestones. This community is lightly grazed by cattle; on sloping limestones it is grazed by rabbits. Briza media has an overall constancy of only II in this community, but achieves a constancy of III in the Dactylis glomerata–Briza media subcommunity. CG8 Sesleria albicans–Scabiosa columbaria grassland is found only on free-draining calcareous, steep slopes of Magnesian Limestone in Durham, principally on rendzinas rich in calcium and magnesium carbonates. The climate is cool and dry, and the community is a plagioclimax vegetation maintained by grazing of domestic animals and rabbits. Briza media has a constancy of IV in CG8. CG9 Sesleria albicans–Galium sterneri grassland is found in the northern Pennine submontane or montane climate, over shallow, freely draining but moist, calcareous lithomorphic soils on drift-free Carboniferous Limestone exposures. It forms an important part of upland farm hill-pasture and as such is frequently grazed, mainly by sheep. In CG9, Briza media reaches an overall constancy of IV and a constancy of V in the Carex capillaris–Kobresia simpliciuscula subcommunity. Briza media occurs with a low constancy (I) in the calcareous grassland community of Festuca ovina–Hieracium pilosella–Thymus praecox/pulegioides (CG7) and in the Festuca ovina–Agrostis capillaris–Thymus praecox grassland (CG10). Briza media is also a component of the following mesotrophic grasslands. MG3 Anthoxanthum odoratum–Geranium sylvaticum grassland. This is a northern submontane community almost entirely restricted to a few valleys in northern England where traditional hay-meadow management occurs, and comprises a dense community of grasses and herbs. Briza media attains an overall frequency of I but a frequency of III in the B. media subcommunity. The constant species for this and the following grassland community are given in Table 2. MG5 Cynosurus cristatus–Centaurea nigra grassland occurs throughout the British lowlands. Briza media has a constancy of III in the subcommunity of Galium verum, found mostly over calcareous bedrocks, and a constancy of III in the Danthonia decumbens subcommunity, mainly occurring on the upland margins of northern England and Wales. The species is also found at a low constancy in the mesotrophic grassland communities of Arrhenatherum elatius (MG1), Arrhenatherum elatius–Filipendula ulmaria (MG2), Alopecurus pratensis–Sanguisorba officinalis (MG4), Cynosurus cristatus–Caltha palustris (MG8), and Holcus lanatus–Deschampsia cespitosa grassland (MG9), and also in the calcifuge sward of Festuca ovina–Agrostis capillaris–Galium saxatile grassland (U4). Briza media is also found as a minor component of the Salix repens–Campylium stellatum dune-slack community (SD14). Briza media is a component of several mire communities; constant species for these are given in Table 3. M10 Carex dioica–Pinguicula vulgaris mire is typically a soligenous mire kept very wet by base-rich, calcareous and oligotrophic waters. This is predominantly a community of north-western Britain, where the cool, wet climate influences the structure and floristics of the vegetation. Most stands are grazed by large herbivores and trampling by these plays a large part in maintaining an open community. Briza media has a constancy of IV in the Briza media–Primula farinosa subcommunity and an overall constancy of II. M13 Schoenus nigricans–Juncus subnodulosus mire is confined to peat or mineral soils irrigated by base-rich, highly calcareous and oligotrophic waters. This community is often found below springs and seepage lines, or on flushed margins of valley mires, and is restricted to the warmer southern parts of Britain. Some stands have been affected by mowing, burning and peat-digging; grazing sometimes affects the floristics and structure of the vegetation. Briza media has a constancy of V in the Briza media–Pinguicula vulgaris subcommunity and an overall constancy of II. M22 Juncus subnodulosus–Cirsium palustre fen-meadow is predominantly a community of moderately mesotrophic and moist, base-rich peats and mineral soils found in lowland southern Britain. It occurs either around well-developed flushes, springs and mires or delineates the influence of more ill-defined areas of surface waters. The identity of the community is maintained by mowing and/or grazing. Briza media has a constancy of IV in the Briza media–Trifolium spp. subcommunity and an overall constancy of II. M26 Molinia caerulea–Crepis paludosa mire is a very local community of moderately base-rich, moist, calcareous peats and peaty mineral soils in the submontane grasslands of the northern Pennines. It can be found either as a stable component around open waters and mires, but also on flushed slopes in soligenous situations, often subject to grazing. Briza media has a constancy of V in the Festuca rubra subcommunity and an overall constancy of III. Briza media is also a minor component in the Molinia caerulea–Cirsium dissectum fen-meadow (M24) and the Cratoneuron commutatum–Carex nigra spring community (M38). Briza media is recorded from Scotland (Birse 1980) from the Polygono–Helictotrichetum pratensis association which is a woodland replacement community created by grazing on rendzinas and shallow brown, calcareous soils. The characteristic species are Avenula pratensis, Carex caryophyllea, Helianthemum nummularium, Koeleria macrantha, and Polygonum viviparum. Birse (1980) also describes B. media as a minor component of the Anthyllido–Rhacomitrietum canescentis association, a pioneer community of river flood plains. In Ireland, B. media is recorded from the mesotrophic grassland Cynosurus cristatus–Centaurea nigra (MG5), which is the typical grassland of well-drained pastures over limestone, usually grazed by cattle. O’Sullivan (1982) records B. media from the Junco–acutiflori–Molinietum association of wet meadows, together with Cynosurus cristatus, Lotus corniculatus, Phleum pratense, Trifolium pratense and Trifolium repens. Briza media is also recorded by Ní Lamhna (1982) from the Festuco–Galietum maritimi sand dune vegetation of Malahide Island, north of Dublin, which is found on middle dunes of grass-dominated, ungrazed or very lightly grazed, vegetation. Differential species are Anthoxanthum odoratum, Briza media, Dicranum scoparium, Koeleria macrantha, praecox and Trifolium repens. Ivimey-Cook & Proctor (1966) recorded B. media from the Galium a calcareous dune community of the Burren, Co. together with Carex Festuca Galium verum, Lotus corniculatus, praecox and and also from the This is a community found on over species are Danthonia vulgaris and Ivimey-Cook & Proctor (1966) also recorded B. media from a calcareous spring community, together with pratensis, Carex Juncus Molinia vulgaris and Briza media has been by the in a lightly and on roadsides in the of in It has been recorded from a in a in Spain, in in the of in in southern Sweden, in in central Europe, in in and in a forest in In continental Europe, B. media occurs in a of of the throughout western these occur on dry steep slopes throughout the in dry in and the soils of the and valleys and also on more slopes of the Briza media also occurs in some of the A range of communities B. media, with a frequency of III and is given in and 5 to and The the edaphic very wide, dry and montane and so a high of plant species associated with B. It is B. media is a which to in grassland et al. 1988), while it as a frequency in ungrazed chalk grassland enclosed for B. media is not a is by the of et al. noted in a B. media more with between the species to be affected by a high of and it is by at normally et al. B. media in grassland and it in meadows which grazed during the of to spring and in & noted in to an mowing this to such as Brachypodium from most of B. Briza media to a grazing it is a component of high constancy in for the calcareous grassland communities of Festuca ovina–Carlina vulgaris and Festuca ovina–Avenula pratensis which are as often heavily grazed by sheep and rabbits, and B. media is also from a woodland plagioclimax community in Scotland, which is maintained principally by the grazing of and (Gauld & Robertson noted the species is grazed by and et al. it is of it is also recorded as frequent on sites heavily grazed by in the species be of a grazing by the with at two for in the of in the et al. B. media is very of on the of more but no have been by the on these noted the of in B. media in the summer following a spring but by the following no to Briza media is usually found as scattered in ungrazed grassland, with a few of by short In grazed grassland and on it as Briza media produces large 2 in the average diameter only about cm. Table Briza media is more in to wet in to dry with and however, is not The of spikelets is also in ungrazed grassland with dry, ungrazed grassland. as absent from woodland (Grime et al. 1988), the species has been found in lightly sites by the where it has and and and in a not different from of ungrazed grassland B. media does not where the is less than c. of The species throughout B. media almost as north as the and to m in the it is and no evidence of damage has been in Britain. noted of B. media no during the and from to B. media is to water the leaves of a and the leaves dry and in and of the leaves also a the of the leaves often a and The species to be principally a as most of leaves are by the of April the of of Briza media does not to to as for in Koeleria macrantha et al. the of B. media in no different from in and roots are to water in Briza media occurs in to wet meadows and is a component of calcareous mire communities it moderately of In a in which to and total conditions for 1 the the leaves and the and root dry there no in weight between normally and to and total for the normally and the not and for the only less than for the with and total lower root dry than of the normally Briza media has a dense fibrous with short rhizomes which in shoots. It to have little in and et al. species which both from and as does B. media, less in than species which from of B. media in in Yorkshire c. 40 while a mean of 30 cm in a grassland on a shallow brown The sheaths of B. media are brown, fibrous and moderately as are the and so to the in Briza media in which mainly by the of short at the of the short In vegetation B. media as of a few Briza media heavily in less in and less so in of 3 in in Yorkshire for a gave a mean dry weight plant of and roots and and the the roots and the of the total dry This is the as shown by Avenula which in in and in the of the about of the total from in grazed limestone grassland in North Yorkshire gave a mean of for the adaxial surface and for the abaxial the made at the length of 20 The occur in between the veins, with more around the middle of the and the Briza media is as by & and a high from July to & noted B. media from the northern calcareous Alps a typically while a association from also B. media strongly et al. B. media ungrazed and with and also ungrazed but with no with grazed, with and noted, however, the effects of grazing not is the of grazing to the influence of the Briza media is a leaves has but a of leaves throughout spring is and the species produces large but a can the extent of the by of at least cm It in the summer and can a of in in a these ranged from to one et al. (1997) B. media largely and

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