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Scleranthus annuus

Taxonomy 

Scleranthus annuus L., Annual Knawel, is a widely accepted species, but its limits are constantly under review. Stace (1997) includes within it S. polycarpos L., as S. annuus L. ssp. polycarpos Bonnier & Layens. It is an annual or biennial plant with inconspicuous green flowers. The size of the achene and the shape of the flower distinguish the two subspecies.

Chromosome No.: 2n = 44 (Stace 2010).

Scleranthus annuus

Photography: G. Toone

Distribution 

It is widespread thoughout Britain, but absent from the very north and the Outer Hebrides. In Ireland it is rare but scattered throughout.

The ssp. polycarpos is recorded mainly in the Breckland, although there are a few records from other parts of the country. Lusby (in Preston et al. 2002) suggests that it is under-recorded.

The species occurs throughout Europe except in the extreme north and is introduced in North and South America, Australia and doubtless elsewhere (Tutin et al. 1993; GBIF)

Its maximum recorded altitude is given by Dickie (1860) as 1200ft (365 m) in Aberdeenshire, although the precise locality is not known.

Scleranthus annuus

Photography: G. Toone

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Scleranthus annuus sl.

Scleranthus annuus ssp. polycarpos

Status 
  • Origin: native. The first record is considered to have been by Thomas Johnson in 1629, at Quex in Kent (Hanbury & Marshall 1899), although Clarke (1900) points out that there may have been some confusion between this species and Alchemilla arvensis.
  • Rarity: rare in Ireland, but not in Britain.
  • Threat: it has recently been added to the British Red List as ‘Endangered’ owing to an apparently significant decline (Cheffings & Farrell 2005). In Ireland, the decline seems even more severe.
  • Conservation: most counties count it as an axiophyte, either of species-rich arable fields or of heaths and upland grassland.
Ecology 

It tends to occur in two distinct habitats - arable fields and dry, heathy grassland. The latter would be more obviously a natural habitat for it, and Hanbury & Marshall (op. cit.), for instance, considered plants in such situations (which they called S. biennis) to be ‘the original form’, whereas ‘the commoner plant [is] a more luxuriant product of cultivated land.’ Rodwell (1991-2000) lists it only as a plant of arable fields in the SE of England, in OV1 Viola arvensis-Aphanes microcarpa and OV5 Digitaria ischaemum-Erodium cicutarium communities.

Further Work 

It is not entirely apparent what is happening to Scleranthus annuus. Its range has not contracted, but it has seemingly declined from its arable situations. Whether the more natural populations have changed or not is an unanswered question. There is need for more study of the putative subspecies, including cultivation experiments to demonstrate that they breed true and possibly genetics work to see what taxonomic rank they merit. More work is needed on its vegetation communities, especially in non-arable habitats.

References 
  • Dickie, G. 1860. The Botanist’s Guide to the Counties of Aberdeen, Banff and Kincardine. Brown, Aberdeen.
  • Hanbury, F.J. & Marshall, F.J. 1899. Flora of Kent. Frederick J. Hanbury, London.
Citation 
Lockton, A.J. & Pearman, D.A. (date accessed). Species account: Scleranthus annuus. Botanical Society of the British Isles, www.bsbi.org.uk.

Fumaria purpurea

Taxonomy 

Purple Ramping-fumitory, Fumaria purpurea Pugsley, was described by Herbert Pugsley in 1902 (Pugsley 1902; 1912) and has no synonyms. It is believed to have arisen as an allopolyploid hybrid of F. muralis and F. officinalis (Lidén 1986).

Chromosome No.: 2n = c. 80 (Stace 2010).

Fumaria purpurea

Photography: A.J.Lockton

 

Identification 

It is a difficult species to identify and, as a consequence, it has been under-recorded in the past. Moreover, not everybody’s records are accepted (see for example, Perring & Walters (1962), where the only records mapped are Pugsley’s, or those in adjacent squares). Some of the key features to look for are the distinctive colouration of the flower, the number of flowers in a raceme, the reflexed pedicels and the large sepals. The Plant Crib (Rich & Jermy 1998) gives more details, but all records need to be backed up by a good specimen and confirmed by an expert (the best herbarium for this taxon is the National Museum of Wales, in Cardiff - contact Tim Rich if you would like to send a specimen).

Distribution 

The Maps Scheme shows many more dots than the Atlas (Preston, Pearman & Dines 2002) with numerous new records post-2000. This is largely due to efforts by Tim Rich at the National Museum of Wales, and surveys commissioned by Natural England and Scottish Natural Heritage (the latter organised by Heather McHaffie at RBGE). The new maps show F. purpurea to be reasonably frequent in a wide band running from Cornwall to Orkney - a very unusual distribution pattern for a British plant. Records of it far outside this range need confirmation. There are a few outliers, such as the site at Lake on the Isle of Wight. It is endemic to the British Isles, having cropped up a few times in the Channel Isles (Stewart, Pearman & Preston 1994), but not elsewhere in Europe. In Ireland it appears to be frequent along the east coast, although not all records seem to be fully vouched.

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Status 
  • Origin: native to Britain and Ireland. Endemic to the British Isles.
  • Rarity: Nationally Scarce in Britain (Stewart, Pearman & Preston 1994) and similarly uncommon in Ireland. Threat: it is given a positive Change Index +0.25 in the New Atlas and may well be increasing in parts of its range.
  • Conservation: a UK Biodiversity Action Plan Priority Species.
Ecology 

Pearman & Preston (op. cit.) describe it as a ‘scrambling herb which grows amongst bushes, on hedge banks, in cultivated fields and waste ground and occasionally on earthy sea-cliffs... in the Isles of Scilly it is found as a weed of bulb-fields.’ A very similar description is given by P.J. Wilson in the New Atlas. More recent work for the BAP (Lockton 2003) shows that it is mostly an arable weed in Scotland and a hedgerow and waste ground plant in England. In Wales it is purely a casual on waste ground and in gardens. Characteristic NVC communities may be W24 Rubus fruticosus underscrub and OV13 Stellaria media - Capsella bursa-pastoris arable weed community (ibid.). The bulb field reference is a bit of a red herring, as it is very rare in the Scilly Isles (Murphy 2009). In Berwickshire it tends to occur in fields of root vegetables (Michael Braithwaite, pers. comm.), and is therefore dependent on the farming practices. In Orkney it also occurs amongst root vegetables, and the RSPB owns many of its sites there.

Further Work 

It should be looked for anywhere within its former range. Good quality photographs of the flowers, backed up by well-pressed herbarium specimens, is the best way to record it. It seems an inappropriate species for the Biodiversity Action Plan, as it is a casual weed of anthropogenic habitats. However, it is clearly of some interest owing to its endemicity, and further studies into its ecology could prove interesting. One unanswered question about this and other species of fumitory is how long the seeds can remain viable, as they often crop up in sites after seemingly long absences.

References 
  • Lidén, M. 1986. Synopsis of Fumarioidae (Papaveraceae) with a monograph of the tribe Fumarieae. Opera Botanica 88: 1-33.
  • Lockton, A.J. 2003. Fumaria purpurea in the British Isles. Report to English Nature by Whild Associates, Shrewsbury. (Available here for downloading, with permission of Natural England; pdf 4.85Mb.)
  • Murphy, R.J. 2009. Fumitories of Britain and Ireland. Botanical Society of the British Isles, London.
  • Pugsley, H.W. 1902. The British Capreolate Fumitories. Journal of Botany 40:129-136 & 173-181.
  • Pugsley, H.W. 1912. The genus Fumaria in Britain. Journal of Botany, 50 (supplement) pp. 1-76.
  • Rich, T.C.G. & Jermy, A.C. 1998. Plant Crib 1998. Botanical Society of the British Isles, London.
Citation 
Lockton, A.J. (date accessed). Species account: Fumaria purpurea. Botanical Society of the British isles, www.bsbi.org.uk.

Ambrosia artemisiifolia

Taxonomy 

Scientific name: Ambrosia artemisiifolia L.

Common name: Ragweed (not to be confused with Ragwort, Senecio jacobaea).

Chromosome No.: 2n = 36 (Stace 2010).

Ambrosia artemisiifolia

Distribution 

It is widely distributed throughout the British Isles, with no particular pattern that relates to soil type, although there is a vague association with urban areas - especially around London for the older records. It appears to have been recorded in Ireland only since the BSBI Atlas in 2002. It is native to North America, but GBIF shows it to occur throughout Europe and in many other parts of the world.

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Status 

Origin: neophyte. It was first cultivated in Britain in the 18th century and was first recorded as a casual in the wild in 1836.

Rarity: if it were a native plant it would be classed as nationally scarce, because there are fewer than 100 dots for it in Britain, but as an alien it has no such status.

Threat: it is increasing in range and probably in abundance, possibly because there are more people putting out bird seed, but plants rarely persist.

Conservation: there is no suggestion that it is of value for nature conservation or poses any threat.

Ecology 

It is an annual weed that occurs as a casual and rarely persists. John Killick (in Preston, Pearman & Dines 2002) describes it as occurring on rubbish tips, in dockyards, arable fields, waste ground and wherever bird seed is put out. As a weed of arable crops it is difficult to control in fields of sunflower, as they are both members of the Asteraceae. In some parts of Europe it has become a rampant pest.

Further Work 

Arguably the most significant attribute of Ambrosia artemisiifolia is that its pollen is hyper-allergenic and, as it flowers late into summer it extends the hay fever season. Hay fever and asthma attacks can be uncomfortable or even life-threatening. The fear is that if it were to become established in the wild in Britain, as it is in Hungary and some other European countries, it could pose quite a hazard to the human population. Joe Crocker of the Food and Environment Research Agency is compiling information on A. artemisiifolia, and particularly wants to know:

a) If it is strictly casual - i.e. plants do not successfully reproduce in the wild.

b) If it chiefly (or only) arrives in birdseed, or if there are other modes of introduction.

If anyone can provide further information on populations they have encountered, please contact Joe 

References 
  • Brandes, D. & Nitzche, J. 2006. Biology, introduction, dispersal and distribution of ragweed Ambrosia artemisiifolia with special reference to Germany. Nachrichtenbl. Deut. Pflanzenschutzd. 58, S 286-291.
  • Chauvel, B., Vieren, E., Fumanal, B. & Bretagnolle, F. 2004. Possibilite de dissemination d'Ambrosia artemisiifolia L. Via les semences de tournesol XIIème Colloque international sur la biologie des mauvaises herbes.
  • Dahl, A., Strandhede, S.-O. & Wihl, J.-Å. 1999. Ragweed – An allergy risk in Sweden? Aerobiologia 15: 293–297
  • Essl, F., Dullinger, S. & Kleinbauer, I. 2009. Changes in the spatio-temporal patterns and habitat preferences of Ambrosia artemisiifolia during its invasion of Austria. Preslia 81, 119-133.
  • Fumanal, B., Chauvel, B., Sabatier, A. & Bretagnolle, F. 2007. Variability and cryptic heteromorphism of Ambrosia artemisiifolia seeds: What consequences for its invasion in France? Annals of Botany 100, 305-313.
  • Genton, B.J., Shykoff, J. A. & Giraud, T. 2005. High genetic diversity in French invasive populations of common ragweed, Ambrosia artemisiifolia, as a result of multiple sources of introduction. Molecular Ecology 14, 4275-4285.
  • Hanson, C.G. & Mason, J.L. .1985. Bird seed aliens in Britain, Watsonia, 15, 237-252.
  • Kiss, L. & Beres, I. 2006. Anthropogenic factors behind the recent population expansion of common ragweed (Ambrosia artemisiifolia L.) in Eastern Europe: is there a correlation with political transitions? Journal of Biogeography 33, 2156-2157.
  • Laurer, V.M., Beitzinger, S. & Huber, K. 2009. Neophyten-Ausbreitung durch Vogelfutter. Anteil und Keimfähigkeit von Samen der Beifuß-Ambrosie (Ambrosia artemisiifolia) . Naturschutz und Landschaftsplanung 40, 244-247.
  • Lavoie, C., Jodoin, Y. & de Merlis, A.G. 2007. How did common ragweed (Ambrosia artemisiifolia L.) spread in Quebec? A historical analysis using herbarium records. Journal of Biogeography 34, 1751-1761.
  • Rich, T.C.G. 1994. Ragweeds (Ambrosia L.) in Britain. Grana 33, 38-43.
  • Vitalos, M. & Karrer, G. 2008. The contribution of bird seed, traffic and mowing machines to the spread of Ambrosia artemisiifolia. – In: Pyšek P. & Pergl J. (eds), Towards a synthesis: Neobiota book of abstracts, p. 120, Institute of Botany, Pruhonice.
Citation 
Lockton, A.J. & Crocker, J. (date accessed). Species account: Ambrosia artemisiifolia. Botanical Society of the British Isles, www.bsbi.org.uk.

Avena strigosa

Taxonomy 

In Scots the name for oat is ‘ait’ or ‘ate’ and A. strigosa on Shetland and Orkney is Shetland oat or Shetland ate. On the Western Isles it is usually referred to as small oat in contrast to big, mainland or white oat, Avena sativa. The vernacular Gaelic name for small oats given by crofters is Corc beag – small oat in contrast to Corca mòr, big or mainland or white oats. On Tiree it was named Tiree oat.

Chromosome No.: 2n = 14, 28 (Stace 2010).

Avena strigosa

Distribution 

Seed cleaning and seed certification have reduced its occurrence as a weed to the point of extinction, and records in the New Atlas for mainland Britain are mainly as bird feed spill. The concentration of records for the Southern Outer Hebrides in the New Atlas reflects its occurrence as a weed associated with cultivation on the Uists. This was checked in BSBI-funded fieldwork in 2006 (Scholten et al. 2008).

As a crop it has disappeared from former stronghold Wales (Chater 1993) and from most parts of Western Scotland. Few growers on Shetland and Fair Isle use it, mainly for crafts such as chairs and basketry. The 540 hectares of small oat in cultivation on the Uists form one of the largest remaining areas of cultivation of this ancient crop in Europe, and the largest area of surviving landraces in Britain.

BSBI Hectad Map 

Click on the map to view full-size on the BSBI Maps Scheme website.

Status 

Origin: a non-native synanthropic species. It is not considered an archaeophyte because it does not naturalise (Preston 2004).

Rarity: as a crop, it is a landrace, with local varieties grown and seed saved on farms over generations by farmers, or in Scotland, crofters.

Threat: many local varieties have gone extinct, including the Welsh varieties and the Tiree oat. Shetland oat is severely threatened and the Fair Isle grower is retiring.

Conservation: for cultivated plants, no Red Data List or equivalent of Species Action Plan exist.

Ecology 

Pankhurst (1991) lists it as a diagnostic species for the weed community of the Chenopodium album - Viola tricolor subsp. curtisii association of the cultivated machair of North and South Uist. As a crop, small oat is usually grown in a mixture with rye and/or bere barley on the narrow strip of coastal grasslands, the machair. Soil nutrient deficiencies, alkalinity, salt spray in combination with high rainfall and high winds give rise to very marginal agricultural conditions (Grant 1979). The local landraces are yielding under low-input conditions. Mainland oat (A. sativa) would require spraying with copper and manganese in order to produce straw or grain. The traditional rotation with natural fallow of 2 to 3 years is associated with phase-specific weed communities (Kent 1996).

Avena strigosa habitat

 

Further Work 

Continued inventory of cultivated populations. Especially for Skye and Kyle, recordings are needed and BSBI members are requested to report.

Genetic diversity study from different parts of the UK and Europe.

Study of conservation policy methods to support maintenance of landraces.

You can help! Please record occurrences of cultivated A. strigosa to maria.scholten@hotmail.com

References 
  • Angus, S. 2001. The Outer Hebrides: Moor and Machair. SNH
  • Chater, A.O. 1993. Avena strigosa Schreb., Bristle Oat and other cereals as crops and casuals. In Cardiganshire, V.C. 46 Welsh Bulletin of the BSBI, no 55, pg. 7-14
  • Fenton, A. 1978. The Northern Isles: Orkney and Shetland. John Donald Publishers Ltd. Edinburgh
  • Grant, J.W. 1979. Cereals and grass production in Lewis and the Uists. Proc. Roy Soc Edinb 77B: 527 –533
  • Kent, M., Weaver, R., Gilbertson, D., Wathern, P. & Brayshay, B. 1996. The present-day machair vegetation of the southern Outer Hebrides. In: D. Gilbertson, M. Kent & J. Grattan (eds) The Outer Hebrides: the last 14,000 years, 133-145. Sheffield University Press, Sheffield.
  • Marquand, C.V.B. 1922. Varieties of Oats in Cultivation. WPBS bulletin No 2
  • Pankhurst, R. 1991. The Flora of the Outer Hebrides, British Museum
  • Podyma, W. 1993. Genetic resources and variability of Avena strigosa Schreb. Schreb., s.l. In: Freson E.A. Koenig, J. Schnittenhelm, S. (eds) Report on the 4th meeting of the ECP/GR Avena working group, IBPGR Rome, pg. 13-29.
  • Preston, C. D., Pearman, D.A. and Hall, A.R. 2004. Archaeophytes in Britain. Botanical Journal of the Linnean Society 145: 257-294
  • Scholten, M., N. Maxted, B. Ford-Lloyd and N. Green (in press) Hebridean and Shetland Oat (Avena strigosa Schreb.), and Shetland cabbage (Brassica oleracea L.) landraces: occurrence and conservation issues BIOVERSITY/FAO PGR Newsletter
  • Scott, W. & R. Palmer 1987. The flowering plants and ferns of the Shetland Islands. The Shetland Times Ltd. Lerwick
  • Stace, C.A. 1997. New Flora of the British Isles, 2nd ed. Cambridge University Press, Cambridge.
Citation 
Scholten, M. (Date accessed). Species account: Avena strigosa. Botanical Society of the British Isles, www.bsbi.org.uk.

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