Flora of Oxfordshire

This page provides systematic lists of all the stoneworts, bryophytes (mosses, liverworts and hornworts) and vascular plants (clubmosses, horsetails, ferns, gymnosperms and flowering plants) recorded from the vice county of Oxfordshire (VC 23) — click on the panels below to reveal each list. The lists include the results of assessments of various statuses, such as native or alien status and national or local conservation status, and these together with explanations of the headings and sources are also described. The lists are works in progress, not least because new taxa keep appearing to add to them!

There have been four printed floras of Oxfordshire: The most recent flora has been drawn on in the compilation of the lists below. It is an excellent source of information on the physical geography of the county and the fortunes of the flora over the last four centuries.

Stoneworts form a division of large aquatic green algae, comprising only a single family (Characeae). The stonewort recording scheme is run by the Botanical Society of Britain and Ireland, which has adopted these large complex-looking algae as one of their own. Thirteen species of stonewort have been recorded from the vice county of Oxfordshire, all of which are native.

Stoneworts are only occasionally encountered in Oxfordshire, found most often in new ditches or cleared-out ponds. They are poor competitors, requiring a clean, nutrient-poor, calcareous aquatic environment free of competition from vascular plants, conditions that are uncommon in our usually dry and eutrophicated lowland landscape. As such, most of our stoneworts are listed on the county Rare Plant Register. However, stoneworts are seldom recorded and so our understanding of their local distribution and status is not complete. Although they have not been widely studied in the county, two of the best areas for stoneworts are the Lower Windrush Valley and Otmoor, which are officially recgonised as Important Stonewort Areas. Otmoor supports a dwindling population of the rare Tolypella intricata.

The scarce Tolypella glomerata near Charlton-on-Otmoor, 2017.

Vascular plants are unsurprisingly the most well-recorded part of the Oxfordshire flora, with records dating back to at least the 16th century. One of the earliest was of Teucrium scordium (water germander) found by John Gerard the famous herbalist at Rewley in 1597, a species that is sadly long extinct in the county. Since then a total of 2,586 distinct taxa, including microspecies, has been amassed with 1034 native species, 133 native hybrids, 121 archaeophyte species and 898 alien species.

Like any other county Oxfordshire has its special plants, and for some of these plants we have national or international responsibilities to look after them. The county boasts perhaps the only site left in Britain and Ireland for Apium repens (creeping marshwort), nearly the last for Viola persicifolia (fen violet) outside of Ireland, and several species for which the wider Cotswolds are important, such as Microthlaspi perfoliatum (Cotswold pennycress), Salvia pratensis (meadow clary) and Stachys germanica (downy woundwort). These and many other locally and nationally rare and threatened plants are carefully monitored and conserved by volunteers of the Oxfordshire Flora Group.

Left: Viola x ritschliana, the hybrid between V. persicifolia (fen violet) and V. canina (dog violet), growing at Otmoor, a hotspot for rare plants and boasting what must be some of the finest meadows in the country. Right: Ophrys insectifera (fly orchid), a now very local species of the Chilterns, an important area for orchids.

The headings and terms used in the lists above are explained in the table below, and references for nomenclature and statuses for are given. The lists are derived from the following sources:

Taxon / Authority
Scientific name and authorities following the works below, including any qualifer, e.g. aggregate.
  • Bryophytes — Hill, M.O., Blackstock, T. H., Long, D.G, Rothero G.P. (2008) A checklist and census catalogue of British and Irish Bryophytes. British Bryological Society
  • Stoneworts — Bryant, J.A., Stewart, N.F., Stace, C.A. (2002) A checklist of Characeae of the British Isles. Watsonia 24: 203-208
  • Vascular plants — C.A. Stace (2010) New Flora of the British Isles. Cambridge University Press
Group Family Rank
Taxonomic group, e.g. moss, fern Taxonomic families, following the arrangements of the cited nomenclatural works (i.e. APG III for vascular plants) Taxonomic rank of the taxon, e.g. species, hybrid
Hectads Tetrads
Number of 10km x 10km national grid squares (hectads) with any record (native or otherwise) of taxon, with percentage out of the 40 hectads covering the vice county Number of 2km x 2km national grid squares (tetrads) with any record (native or otherwise) of taxon, with percentage of the 597 tetrads covering the vice county
VC 23 status
The following statuses are assigned to vascular plants:
  • Native — indigenous to the vice county
  • Alien — non-native, introduced to the vice county since 1500 (also known as neophytes). This concept covers the plethora of recent garden escapes, but some much older introductions are also considered neophytes, e.g. Malva setigera (hairy mallow).
  • Archaeophyte — non-native, introduced to the vice county before 1500, based on REF. Often agricultural, e.g. Papaver rhoeas (common poppy).
Status has been based on the hectad statuses assigned in the New Atlas of the British Flora, BSBI (2002), The Flora of Oxfordshire, H.J. Killick, R. Perry, S. Woodell (1998) and personal judgement. Some taxa have been assigned mixed statuses to reflect their ambiguous situation, including taxa that have both alien and native subspecies, taxa of uncertain status or plants that are scarce as natives but frequent as aliens, e.g. Aquilegia vulgaris (columbine) or Iris foetidissima (stinking iris). Where the balance tips the other way, frequent native taxa that might only occasionally be introduced are given as native, e.g. planted native trees/shrubs, or sown wildflowers. Halophytes native to GB that have colonised salted roads, e.g. Cochlearia danica (Danish scurvygrass) are accorded native status. The hectad and tetrad occupancies reflect all records regardless of status.
Legal / conservation status
The following legal and conservation statuses are listed:
  • Schedule 8 — legally protected taxa listed on Schedule 8 of the Wildlife and Countryside Act 1981 (as amended).
  • Schedule 9 — invasive non-native species listed on Part II of Schedule 9 of the Wildlife and Countryside Act 1981 (as amended).
  • Section 41 — species of principal importance, listed in accordance with Section 41 of the Natural Environment and Rural Communities Act 2006 (i.e. former Biodiversity Action Plan priority species).
  • National Status — follows:
    • The BSBI national status checklist for vascular plants (NR=Nationally Rare, NS=Nationally Scarce)
    • Stewart, N.F, Church, J.M. (1992) Red Data Books of Britain & Ireland: stoneworts. JNCC. (EN= Endangered)
  • Red lists using IUCN threat categories (EW=Extinct in the Wild, CR=Critically Endangered, EN=Endangered, VU=Vulnerable, NT=Near Threatened, DD=Data Deficient, WL=Waiting List):
    • The Vascular Plant Red Data List for Great Britain, C.M. Cheffings and L. Farrell (Eds.) et al (2005).
    • Vascular Plant Red List for England, Stroh et al (2016)
  • Rare Plant Register (RPR) – status of plants on the provisional RPR for the modern county of Oxfordshire.

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