Sorbus torminalis

Taxonomy 

Name: Sorbus torminalis (L. ) Crantz., Wild Service-tree.

An obsolete name for it is Chequers Tree, which often still turns up in Pub names in England.

Chromosome no.: 2n = 34 (Stace 2010).

Sorbus torminalis

Photography: A.J. Lockton

Distribution 

Widespread in England and Wales, absent from Scotland, Ireland, Man and the Channel Isles, except as an uncommon introduction. The number of records of S. torminalis in Britain has been steadily increasing for a century or so. This is thought to be largely due to better recording, because it is easily overlooked. However, it is possible that part of the apparent increase is real, either due to natural spread or deliberate planting. It is a common species throughout western Europe extending eastwards at least to Asia. Many infraspecific forms have been described.

BSBI Hectad Map 

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

Status 
  • Origin: native in Britain.
  • Rarity: it is a widespread but very localised species.
  • Threat: there is no obvious threat to it in Britain. Cheffings & Farrell (2005) give its status as “Least Concern” in Britain.
  • Conservation: because it is widely considered an ancient woodland indicator, S. torminalis is often highly valued as a plant of conservation interest. Wherever it occurs as a native it is listed as an axiophyte.
Ecology 

It occurs in three main habitats: ancient woodland on calcareous soils; limestone and other rock outcrops; and hedges. This mirrors the distribution of other species of Sorbus. Given that these are very widespread habitats, it is perhaps surprising that it is so uncommon. Rodwell (1991-2000) gives just two vegetation communities for it: W5 Alnus glutinosa and W8 Fraxinus excelsior woodlands. W8 is the typical climax community on drier calcareous soils in England & Wales, and presumably accounts for the majority of sites. W5, however, is an acid wet woodland type and seems somewhat incongruous.

Further Work 

Although this is a popular tree, most of what is written about it is folklore, and scientific studies are rare. Roper (1993) studied its distribution, focusing on its affinity with various soil types. There are many question left unanswered, though, including...

  • Why is it so rare?
  • What are its vegetation communities?
  • What are its mechanisms for reproduction and dispersal?
  • What is its natural range in Britain, and to what extent is it planted?
  • Is it increasing or decreasing?
  • What is its world distribution?
References 
  • Roper, P. 1993. The distribution of the Wild Service Tree, Sorbus torminalis (L.) Crantz, in the British Isles. Watsonia 19, 209-229
Citation 
Lockton, A.J. (date accessed). Species account: Sorbus torminalis. Botanical Society of the British Isles, www.bsbi.org.uk.

Ribes spicatum and Ribes rubrum

Taxonomy 
Ribes spicatum Robson, Downy Currant.

Synonyms:

  • R. petraeum auct. non Wulfen
  • R. pubescens (Hartm.) Hedl.
  • R. glabellum (Trautv. & CA Meyer) T. Hedl.
  • R. hispidulum (Jancz.) Pojark.

Warburg (1962) notes that some cultivated redcurrrants (R. rubrum) are (ancient?) hybrids with R. spicatum and might escape into the wild, but there is no evidence that this occurs. Although the two species occasionally coexist in the wild, I have examined several mixed populations without finding intermediates, perhaps because fruit-set in R. spicatum is rather unusual (below).

Chromosome No.: 2n = 16 (Stace 2010). 

Ribes - main photo
Photography: A.J. Richards
Identification 

R. spicatum is a much misunderstood and under-recorded species that is frequently mistaken for R. rubrum. Most accounts concentrate on rather obscure floral characters, but as flowering occurs very early, usually in mid April, and many plants fail to flower, an attempt at identification is often abandoned unnecessarily. A further confusion results from the loss of the fine pubescence from the upper surface of the leaf as the season progresses in R. spicatum; however, hairs usually persist on the leaf margin (lens needed). Any pubescence on leaves of R. rubrum is scattered and the hairs longer and coarser. Indumentum varies across the European range. R. glabellum has been used for glabrous arctic and subarctic varieties, while R. hispidulum from eastern Europe and Russia has small hairy leaves.

In fact R. spicatum and R. rubrum have a different ‘jizz’. The leaves of R. spicatum are matt and a rather dull, dark green; they are held characteristically at an approximate right-angle to the stem, and the old wood is dark; even blackish. In R. rubrum the leaves are shiny, a rather pale yellowish green, they are more floppy, and the wood is a pale orange-brown. The petiole is green in R. spicatum but orange-ish in R. rubrum. Definitively, the sinus of the leaf-base exceeds 90 degrees and may approach 180 degrees in R. spicatum, but is 90 degrees or less in in R. rubrum. With practice, bushes can be accurately identified from a distance of 10 m or more, even in mixed populations.

It is worth emphasising that several floral characteristics that appear in most floras seem not to be reliable. Warburg (1962) said that the inflorescence in R. spicatum is ‘erect to....spreading, but not pendant except in fruit’. However, the inflorescence is usually pendant from the first, and is never erect in my experience. The difference in hypanthium shape between ‘cup shaped (spicatum) and saucer-shaped (rubrum)’ (Stace 1997) sounds useable, but is far from straightforward unless you have the two types together. Although the absence of a visible connective to the anther in R. spicatum is a reliable character if a lens is used, it is extremely fiddly, and anthers are evanescent and lost very early in the season.

Ribes spicatum

Ribes rubrum

Leaves of Ribes spicatum  (above) and R. rubrum (below).

Photography: A.J. Richards

Distribution 

Apparently curiously absent from south-east, south-west and much of western Scotland, where it should be looked for. In this context, its occurrence in high rainfall districts of Islay and northern Skye is difficult to explain. Although stated by Warburg (1962) to occasionally escape from cultivation, and to have been hybridised with redcurrants, there is little evidence that it has been cultivated in the UK in the modern era, or escapes (Webb 1993) -  and records outside the native distribution and habitats should be reviewed critically. Typically, plants of R. rubrum and R. nigrum are found close to the nearest habitation, and as the natural riverside woodland is penetrated further R. spicatum finally appears. As clones can be very long-lived, it tends to be persistent in the absence of major habitat change, but is a poor coloniser in the absence of much regeneration from seed. A species of boreal woodlands, apparently extending eastwards to Manchuria (Warburg 1962).

BSBI Hectad Map 

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

Status 
  • Origin: native. The berries are edible and so likely to have been informally cultivated through its native range, but replaced by R. rubrum and possibly hybrids in modern times, and rarely if ever seen in cultivation today, except possibly in eastern Europe (Webb 1993).
  • Rarity: very local with a narrow habitat niche and absent from many apparently suitable sites, perhaps due to its poor colonisation abilities, but stable and persistent in most previously known sites after 50 years or more.
  • Threat: probably low as most of the streamside woodlands in which it is found are unlikely to be deforested.
  • Conservation: classed as an axiophyte, probably as a good indicator of ancient riverine woodland.
Ecology 

In North-east England at least, Ribes spicatum has a narrow and distinctive habitat niche. It occurs mostly in upland areas, but at low altitudes (rarely above 200 m) in native woodland within 50 m of shallow, rocky rivers and streams, usually in ‘denes’ (steep declivities in sandstone country). It is usually rooted amongst water-borne boulders in areas where the water course regular changes position, either in raised islands or on steep banks, often in considerable shade, most usually from alders (Alnus glutinosa). It appears to compete poorly with comparable life-forms, and persists in a tension zone between the erosive powers of flooding, and the establishment of a dense, shrubby ground layer. It has a wide range of associates, but seedling sycamore (Acer pseudoplatanus), Geum urbanum, Chrysosplenium oppositifolium, Dryopteris dilatata, D. filix-mas, Allium ursinum, Urtica dioica and Luzula sylvatica are amongst the most typical. Most localities classify as W6 Alnus glutinosa-Urtica dioica woodlands (Rodwell 1991). It is noteworthy that this habitat bears little relationship to that cited in Warburg (1962) ‘Woods on limestone’ or that in Preston et al. (2002) ‘a shrub of limestone woods.......’, and although it does occur rarely in this habitat (including grikes in limestone woods) in Lancashire and Yorkshire, nevertheless, it nearly always occupies a streamside position, and is much more commonly met with in the sandstone denes of Northumberland and Durham

Ribes spicatum typically forms clonal individuals, varying from one to more than 100 stems. Large plants may cover 10 m or more and are considered to be of a considerable age. They are deep-rooted and capable of withstanding considerable flooding, although it seems that repeated flooding and root erosion can eventually lead to the death of large parts of the clone, and many individuals tend to be partially senescent. Many plants, especially those in deep shade, flower rarely, and fruit-set is usually very poor. Flowers are visited by bees, especially queen Bombus spp., but plants are probably self-incompatible. It is notable that fruit-set is best where several flowering individuals occur within a relatively small area (<100m). Seeds are presumably dispersed by birds, but in most populations evidence of regeneration by seed is absent.

Further Work 

Further studies might concentrate on the extent to which R. spicatum and R. rubrum remain distinct in the wild. If intermediates are found, are these the result of recent hybridisation, or do they reflect the complex origin of R. rubrum (Simmonds 1976)? These questions would probably be best answered using molecular markers such as those from AFLPs, but a simple examination of e.g. pollen stainability might indicate whether wild R. spicatum is introgressed by R. rubrum. It would be interesting to attempt to age large clonal individuals, but this may be very difficult as the plant may be far older than the oldest stem. Possibly woody stocks show annual growth rings?

References 
  • Bolkhovskikh Z et al. 1969. Chromosome numbers of Flowering Plants. Acad. Sci. URSS.
  • Simmonds NW. 1976. Evolution of Crop Plants. Longman, London. Webb DA. 1993. Flora Europaea I, ed.2. Cambridge UP.
Citation 
Richards, A.J. (date accessed). Species account: Ribes spicatum. Botanical Society of the British Isles, www.bsbi.org.uk.

Quercus cerris

Taxonomy 

Name: Quercus cerris L. (1753)

Common name: Turkey Oak

The genus Quercus is notorious for hybridisation and introgression due to weak reproductive isolation mechanisms; it is also subject to a great deal of study, (e.g. Curtu et al. 2007). Lucombe Oak - Quercus x hispanica ‘Lucombeana’ Sweet ex Loud. (1838) - is such a hybrid between Q. cerris and Q. suber, (Cork Oak) that is grown in many botanic gardens (Trehane 2007; Sterry 2007). Putative hybrids between Q. cerris and Q. robur have been recorded in Britain - currently the subject of an MSc research project, (see further work).

Chromosome No.: 2n = 24 (Stace 2010).

Quercus cerris

Photograph: A.J. Lockton

Identification 

The leaf shape of Q. cerris varies greatly between individuals and on the same tree. Leaf lobing is usually more angular and irregular than Q. robur, commonly cut one-two thirds to the midrib, but can be deeper and very fancily lobed, especially on cut branches e.g. hedges. Leaves usually have mucronate tips to the lobes, and are pubescent with stellate hairs, commonly densely so on their lower surface. It differs from the native Q. robur and Q. petraea in that its buds are surrounded by persistent whisker-like stipules. Fruit cupules are covered by patent to reflexed scales up to 1 cm - in contrast to the two British native oaks (Stace 2010; Mitchell 1976).

Quercus cerris

Whisker-like stipules of Quercus cerris

Photograph: K.J. McGinn

 

Distribution 

Q. cerris is native to S Central and SE Europe, extending into SW Asia (Preston et al. 2002). It is a widely planted tree of parks, gardens and roadsides in Britain, but also seeds freely and has so become naturalised, often occurring in mixed stands alongside the native Q. robur and Q. petraea. This neophyte is most common in the southern half of lowland Britain (Preston et al. 2002).

BSBI Hectad Map 

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

Status 
  • Origin: introduced to Britain by J. Lucombe of Exeter in 1735 (Sterry 2007). Documented in the wild since at least 1905 (Preston et al. 2002).
  • Rarity: widespread and common.
  • Threat: it has a change index of +2.32; a dramatic increase that is partly attributable to better recording of aliens, as well as a genuine increase (Preston et al. 2002).
  • Conservation: no conservation status.
Ecology 

Q. cerris has a fast growth habit, and seemingly tolerates a range of soil types; most common on free draining, sandy and acidic soils, but is also known on calcareous soils (Sterry 2007; Preston et al. 2002). Four non-native cynipid gall wasps, Andricus kollari, A. lignicola, A. quercuscalicis and A. corruptrix, have become established in the British Isles since the introduction of Quercus cerris. Their interesting lifecycles involve host-alternating generations, with a sexual generation on the male flowers of Q. cerris in spring, and an agamic (asexual) generation on the acorn cups of British native oaks, (Q. robur, Q. petraea and their hybrid Q. x rosacea) in autumn, (Schonrogge et al. 2002). Infection results in a reduction in the acorn crop of the British Oaks as development of a sexual gall replaces an acorn, but galling rates have been shown to vary between the gall wasp species over time, and differ greatly between individual trees, (Collins et al. 1983; Schonrogge et al. 2002)

Further Work 

There has been debate over the existence of hybrids between Quercus cerris and the native Q. robur. Specimens have been documented in Britain over the past few decades that have persistent stipules and pubescence  characteristic of Q. cerris, but with leaf lobation more like Q. robur. Although the genus Quercus is notorious for hybridisation, it usually occurs between more closely related species, that is within the same taxonomic group known as sections. Q. cerris and Q. robur are in different sections of subgenus Quercus - section Cerris and section Quercus respectively. A study invloving DNA analysis with nuclear microsatellite markers has provided molecular evidence suggesting these possible hybrids are in fact the pure species, Q. cerris, with confusion seemingly having arisen due to the extreme variability in leaf shape of Q. cerris, (McGinn 2010). This conclusion is supported by the opinions of many botanists in disallowing older records of the putative hybrid, e.g. Stace 2010.

Please contact me, Kevin McGinn (k.j.mcginn@student.reading.ac.uk) for more details.

References 
  • Collins, M., Crawley, M. J. & McGavin, G. C. 1983. Survivorship of the sexual and agamic generations of Andricus quercuscalicis on Quercus cerris and Q. robur. Ecological Entomology, 8: 133-138.
  • Curtu, A.L., Gailing, O. & Finkeldey, R. 2007. Evidence for hybridization and introgression within a species-rich oak (Quercus spp.) community. BMC Evolutionary Biology 7: 218
  • McGinn K. J. (2010) A morphological and molecular study of putative hybrids between Quercus robur and Q. cerris in Britain. MSc Plant Diversity thesis, University of Reading.
  • Mitchell A. 1976. Trees of Britain and Northern Europe. Collins.
  • Schonrogge, K., Walker, P. & Crawley M. J. 1998. Invaders on the Move: Parasitism in the Sexual Galls of Four Alien Gall Wasps in Britain (Hymenoptera: Cynipidae). Biological Sciences, 265: 1643-1650
  • Sterry, P. 2007. Collins Complete British Trees. HarperCollins Publishers.
  • Trehane, P. 2007. The Oak Names Checklist. http://www.oaknames.org

 

Citation 
McGinn, K.J. 2010. Species account: Quercus cerris. Botanical Society of the British Isles, www.bsbi.org.uk.

Pyrola media

Taxonomy 

Name: Pyrola media Sw., Intermediate Wintergreen.

No known synonyms.

 

A shortly rhizomatous perennial herb about 15 cm tall with a loose rosette of round, stalked, toothed leaves and a spike of white bell-shaped flowers. Distinguished from other Pyrola species by its long (4-6 mm) straight stigma which protrudes from flower and which widens immediately below the stigma-lobes (Stace 1997); but difficult to distinguish from other Pyrola species in the vegetative state, when the number of teeth is a helpful but non-definitive distinguishing feature.

 

Pyrola media

Photography: L. Campbell

Chromosome No. 2n = 46 (Stace 2010).

Distribution 

Pyrola media occurs throughout the boreal montane zone of Europe, from arctic Scandinavia to mountains of central Europe, the Caucasus and Asia Minor. In Britain it is frequent in north and central Scotland and extremely local in southern Scotland and Northern Ireland and western Ireland.

In England it is confined to a few sites in Northumberland, Durham and Yorkshire. It was last recorded in Sussex in 1887 and the Wyre Forest on the Worcestershire/Shropshire border in the 1970s. There is a scattering of other English records (e.g. Cheshire, S. Lancs., Shropshire) but many of these are probable errors for P. minor with which it was often confused in the past.

Its strongholds in Scotland are centred on the Cairngorms. Whilst it extends to Skye, and other Inner Hebridean islands, it is absent from the Outer and Northern Isles. It is usually found as scattered individuals in small populations, and is not known to be abundant anywhere in the British Isles.

Lowland to 550 m in Coire Garbhlach, above Glen Feshie in Easterness.

Pyrola media

Photography: J. McIntosh

BSBI Hectad Map 

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

Status 
  • Origin: native
  • Rarity: Nationally Scarce (Stewart et al. 1994).
  • Threat: Vulnerable (Cheffings & Farrell 2005). It is included on the Scottish Biodiversity List on account of its decline of >25% over a 25 year period. The New Atlas (Preston et al. 2002) indicates a significant decline since the 1960s with a change index of -1.09. The Irish Red Data Book (Curtis & McGough 1988) lists the species with a Threat Number of 6 – equivalent to ‘Rare but not threatened.’
  • Conservation: although not a UK Biodiversity Action Plan priority species, it was selected as a target for concerted conservation action in Scotland by its inclusion in Scottish Natural Heritage’s Species Action Framework, 2007.
Ecology 

A rhizomatous mycorrhizal evergreen perennial woody herb of well drained, mildly acidic to slightly basic soils in woods and heaths, Pyrola media occurs in the mossy dwarf-shrub field layer in W18 Pinus sylvestris – Hylocomium splendens woodland (Rodwell 1991). It also grows occurs in the H16 Calluna vulgaris – Arctostaphyllos uva-ursa heath.

In the Burren, Western Ireland, it occurs on the summits of limestone hills where there is sufficient peat development to support dwarf-shrub heath.

The decline in Pyrola media in woodlands has been attributed to unfavourable management, with some populations lost to afforestation. Heathland populations have variously been affected by changing grazing practices and decreased muirburn. There is over-grazing in some areas and no grazing in others, leading to a very short turf in which some herbaceous species are grazed out, or a rank growth of heather which shades them out (SNH 2007). In some cases heavy grazing has even led to the conversion of heather moorlands to grassland. Burning may also have lead to losses, although this may be less of an issue now with a reduction in muirburn in recent years.

Under-grazing may also result in populations going undetected and unrecorded. An additional factor in the apparent decline of Pyrola media is that there is thought to have been some previous confusion with P. minor, with which it often grows. The situation is further complicated by the reluctance of some P. media populations to flower (especially in N. Ireland and northern Scotland).

Further Work 

Particularly interesting issues to investigate would include:

  • The extent and rate at which it spreads clonally.
  • The persistence or transience of populations.
  • Is it dependent on Tricholoma fungi like other Ericaceae members?
  • The incidence of flowering.
  • Is it self-compatible?
  • Its seed ecology and seed dispersal.
  • The effects of shading on populations.
  • Whether there are any published papers on Pyrola media in Scandinavia
References 
  • Curtis, T.G.F. & McGough, H.N. 1988. The Irish Red Data Book. Wildlife Service Ireland, Stationary Office, Dublin.
  • Poland, J. & Clement, E.J. 2009. The Vegetative Key to the British Flora. John Poland, Southampton.
  • Stewart, N., 2005. Report on the Selection of Vascular Plants for the Scottish Biodiversity List. Report by Scott Wilson, Edinburgh for Scottish Biodiversity
  • SNH. 2007. A Five Year Species Action Framework. Scottish Natural Heritage, Perth.
Citation 
McIntosh, J. & Walker, K.J. (Date accessed). Species account: Pyrola media. Botanical Society of the British Isles, www.bsbi.org.uk.

Monotropa hypopitys

Taxonomy 

Monotropa hypopitys L., Yellow Bird’s-nest, is the only European species in the family Monotropaceae (Fl. Europaea), although some authors include it within either the Pyrolaceae or the Ericaceae.

Synonym: Hypopitys monotropa Crantz.

It is considered to have two subspecies (Stace 1997), but morphology is not always reliable and only a handful of specimens in the U.K. have had their chromosome number checked to date.

  • ssp. hypophegea (Wallr.) Holmboe which is glabrous and has a chromosome number 2n = 16 (Stace 2010).
  • ssp. hypopitys, which has pubescent stamens, carpels and petals; 2n = 48 (Stace 2010).

Monotropa hypopitys is a saprophytic plant with no chlorophyll. Its flowering stems above ground are whitish in colour and up to 30cm tall.

Monotropa hipopitysMonotropa hipopitys

Monotropa hypopiitys in flower (left) and fruit (right)

Photography: A.J. Lockton


Distribution 

Widespread throughout the British Isles, but increasingly rare towards the north and west. Absent from the Isle of Man, the Scillies, and the Northern and Western Isles. It occurs throughout the Northern Hemisphere, being widespread but thinly scattered in North America, Europe and Asia. In America it is known as Indian Pipe or Pinesap and sometimes listed as a different subspecies: photographs of it on American web sites often show plants with a reddish tinge, which does not seem to occur in British plants.

BSBI Hectad Map 

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

Monotropa hypopitys

Monotropa hypopitys ssp. hypophegea

Monotropa hypopitys ssp. hypopitys

Status 
  • Origin: native. It was first recorded by Robert Plot at Stokenchurch in 1677 (Clarke 1900), although he mentions earlier records by John Goodyer (1592-1664), which must pre-date this.
  • Rarity: not quite a Nationally Scarce species in Britain, being recorded in 103 hectads in the New Atlas (Preston et al. 2002). In Ireland and Scotland it would certainly count as a rare plant.
  • Threat: its status in the JNCC Red List (Cheffings & Farrell 2005) is ‘endangered’ - an assessment based on the Change Index, which shows it to be declining in Britain. Rumsey, in the New Atlas, also describes it as having suffered a prolonged decline.
  • Conservation: several county recorders have listed it as an axiophyte, but it is not quite obvious which BAP habitats it occurs in. It is debatable whether it really warrants such a status, and more research is needed.
Ecology 

Monotropa contains no chlorophyll, and was until recently thought to be saprophytic (deriving nutrients from decaying leaf litter) but recent research shows that it is actually epiparasitic, using Tricholoma fungi to extract nutrients from living trees in its vicinity (Leake et al. 2004). It is usually found in woods or in scrub. Rumsey (in the New Atlas, op. cit.) describes it as most frequent under Beech and Hazel on calcareous soils, and under pines on more acid substrates. It is sometimes also found in dune slacks, where it is associated with Creeping Willow, Salix repens. It is not listed by Rodwell (1991-2000) as a component of any NVC community. The maps show that in the past it was strongly associated with limestone and chalk soils in the south of England, but that seems a less obvious association in the more recent data. It is a rather transient plant, sometimes appearing in large numbers (hundreds of flowering spikes) at a site, only to disappear within a few years. Sometimes it is found in secondary woodland. It is a lowland plant - the maximum recorded altitude is 395 m, at Buxton, Derbyshire.

Further Work 

The Maps Scheme, which divides records into five date classes (rather than the two used in the Change Index), shows no obvious change in its range. Whether there is any decline in abundance within its range is more difficult to assess. The Change Index works on the assumption that plants stay in the same place and that recording effort in the more distant past was less than recently. But neither of these may hold true for Monotropa, so an accurate assessment of any change in its abundance requires a different method of calculation. This is one of the outcomes we hope to achieve with the Threatened Plants Project. It would be interesting to study how long populations tend to persist in one place, and whether it is likely to recur there. Its disappearance from sites might be due to competition from other species or from depletion of nutrients - or some other cause. No studies seem to have been undertaken on its vegetation communities and specific niche - e.g. how often it is found in ancient woodland or recent scrub.

References 
  • Leake J. R., Mckendrick S. L., Bidartondo M. & Read D. J. 2004. Symbiotic germination and development of the myco-heterotroph Monotropa hypopitys in nature and its requirement for locally distributed Tricholoma spp. New Phytologist 163, 405-423.
Citation 
Lockton, A.J. & Walker, K.J. (date accessed). Species account: Monotropa hypopitys. Botanical Society of the British Isles, www.bsbi.org.uk.

Hyacinthoides non-scripta, H. hispanica & H. x massartiana

Taxonomy 

The familiar Bluebell, Hyacinthoides non-scripta (L.) Chouard ex Rothm., has a chequered history, having been Endymion non-scriptus (L.) Garke to many British botanists until recently, and before that Scilla non-scripta (L.) Hoffmans & Link and even Scilla nutans Sm. (Clapham, Tutin & Moore 1989). There is more confusion, however, as the native Bluebell in Britain is now joined by a garden escape known as Hyacinthoides hispanica (Mill.) Rothm. and, more commonly, the hybrid between the two, which is correctly called Hyacinthoides x massartiana Geerinck (Stace 1997; BSBI 2007) (syn: H. x variabilis P.D. Sell (Sell & Murrell 1996). There are unresolved questions about the taxonomic status of these taxa, however: whether the ‘Spanish’ Bluebell is the same as the bluebells in Spain and whether it is merely a subspecies of the common Bluebell, as the two apparently hybridise freely (Taylor, in Preston, Pearman & Dines 2002, p. 817).

Chromosome No.: 2n = 16, 24 (Stace 2010).

Hyacinthoides non-scripta

Hyacinthoides non-scripta

Photography: A.J.Lockton

Identification 

There are photographs of all three taxa on this page. For detailed differences between them, the Plant Crib (Rich & Jermy 1998) has a useful table.

Hyacinthoides hispanica

Hyacinthoides hispanica

Photography: A.J. Lockton

Distribution 

Hyacinthoides non-scripta is common throughout Britain. It is absent from some of the most northerly islands, high mountains in Scotland, and some peatlands in East Anglia (Preston, Pearman & Dines 2002). H. hispanica and the hybrid are now almost as widely distributed as the native plant, being widely planted in gardens and near habitation. Both H. hispanica and H. non-scripta are considered to be endemic to western Europe; the former being the rarer and confined, in its native range, to the western part of the Iberian peninsula (Tutin et al. 1980).

Hyacinthoides x massartiana

Hyacinthoides x massartiana

Photography: A.J. Lockton

BSBI Hectad Map 

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

Hyacinthoides non-scripta

Hyacinthoides hispanica

Hyacinthoides x massartiana

Status 

Origin: all three taxa are endemic to Europe, and therefore of considerable conservation importance; but only H. non-scripta is native in the British Isles.

Rarity: none of these three taxa is rare.

Threat: there is not much evidence of an overall decline in H. non-scripta, and the other two are very clearly increasing.

Legislation: in Britain it is illegal, under the Wildlife & Countryside Act 1981, to sell plants of H. non-scripta; and it is illegal to dig up any plant in the wild without the permission of the landowner.

Conservation: Hyacinthoides non-scripta is often considered an ancient woodland indicator and is sometimes classified as an axiophyte, but in most places it is too widespread to qualify. It is also known to persist in heathland and grassalnd after woodland is felled, although it is less able to colonise new sites without help. Some conservation organisations suggest that the Spanish Bluebell is invading and threatening the native species. There has been little attempt to quantify this, and there is currently no scientific reason to be concerned for the survival of either species. Recently, some conservation bodies have allowed the trade in native bluebells to resume under licence (see, for example, a recent article in The Guardian).

Ecology 

Hyacinthoides non-scripta is typically a woodland plant, occurring in calcareous and mildly acid woodlands of all types except the very wettest (Rodwell 1991a). It is sometimes overwhelmingly abundant in the ground flora in the spring, although it dies down by mid-summer and even dead fruiting spikes can be difficult to find towards the end of the season. The most characteristic communities for it are W8 Fraxinus excelsior and W10 Quercus robur woodlands, which are the climax communities over much of lowland Britain. It is often found in grassland, presumably long after woodland is cleared, and under bracken, most typically in U20 Pteridium aquilinum-Galium saxatile grassland (Rodwell 1992, Taylor, ibid.) and in coastal grassland in the MC12 Festuca rubra - Hyacinthoides non-scripta community (Rodwell 2000). Rodwell (1991b) does not list it as a component of any heathland community. The ecology of H. hispanica and H. x massartiana is not well studied. They are rarely seen far from habitation or where garden soil has been tipped on roadsides, and although patches increase in size, they do not appear to spread much from their original planting site (pers. obs.). This raises questions about the fertility and dispersal of the hybrid. Their ability to outcompete native bluebells is often quoted but has yet to be demonstrated empirically.

Further Work 

Scientists at the Natural History Museum have been studying hybridization in bluebells for the last three years and are planning to publish their results in 2008 or early 2009. Visit their web site for updates, and for details of how to contribute. Anyone recording in the countryside might like to note how much the garden escapes spread into wild woodlands, or whether they remain on the edges where they have presumably been planted or dumped.

References 
  • BSBI. 2007. BSBI Taxonomic Database (Leicester). Botanical Society of the British Isles, University of Leicester.
Citation 
Lockton, A.J. (date accessed). Species account: Hyacinthoides non-scripta. Botanical Society of the British Isles, www.bsbi.org.uk.

Gladiolus illyricus

Taxonomy 

Authorities differ about the taxonomic rank of Wild Gladiolus in Britain. Sell & Murrell (1996) and Stace (1997) both treat it as a species - G. illyricus Koch - although Sell hints that it might be sufficiently distinct to be worthy of subspecific rank. A.P. Hamilton considered British plants to be distinct, and coined the name G. illyricus ssp. britannicus for them. The subspecies is (or was) otherwise only found in France, although the population there has now apparently been lost (Stokes, i Wigginton 1999). Others doubt the existence of a distinct subspecies, and possibly of G. illyricus itself. Studies in Spain by students at the University of Birmingham showed no features that would distinguish between G. illyricus and G. communis (Lockton 2006). Since then, Aeron Buchanan at Imperial College, London, has studied the genetics of European gladioli in an attempt to clarify this question, but with inconclusive results. His dissertation includes a good account of its history in Britain and a comprehensive reference list.

Chromosome No.: 2n = 60 (Stace 2010).

Gladiolus illyricus

Gladiolus illyricus. Photography: F.J. Rumsey

Distribution 

G. illyricus is, in Britain, largely restricted to the New Forest, although, contrary to the assertion in Fl. Hampshire (Brewis, Bowman & Rose 1996) it was not first discovered there. It was collected on the Isle of Wight by a Mrs Phillips in 1855 - a year before Rev. Lucas found it in the New Forest. Most recent accounts state that it is in decline in the New Forest, although in fact there are more records, and more populations, now recorded than ever before (data from the TPDB). This could be because it is better recorded and because botanists in the past often used to keep localities secret in order to protect it from collectors. It is a difficult plant to find because it often occurs under bracken, and by the time it flowers it can be completely hidden from view. On the Maps Scheme, several other sites outside Hampshire are recorded. These include casual occurrences around the country. Taxonomic uncertainties have led these records sometimes to be dismissed (only one such dot makes it into the New Atlas), but here they are included unless there is specific evidence to suggest they are incorrect.

BSBI Hectad Map 

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

Status 

There has been much debate about the status of the Wild Gladiolus (Stokes, in Wigginton 1999). It is very difficult sometimes to decide whether a plant is native or not. Gladiolus illyricus (or its close relatives) is common around the Mediterranean basin as an agricultural weed and a casual of waste ground. It would be considered native if it had arrived in Britain, unaided by humans, at least 500 years ago. This would make it part of the natural ecosystem, and it would be expected to be a constituent of a semi-natural vegetation community and to have as many pests, parasites and associates as any other native species. None of these things has yet been demonstrated. If it is a recent introduction (neophyte), however, it would be less likely to occupy a discrete niche within a natural vegetation community, and would probably have fewer associations with other native organisms. It is important not to overstate the significance of native status, which is as much a political as a scientific concept. But understanding the dispersal processes of a species is an important question from the point of view of nature conservation, because if G. illyricus is a southern, ruderal species, it might be expected to increase if the climate continues to warm and more waste land is created by processes such as agriculture and mineral extraction; whereas a native species might find itself endangered by changes in the climate and destruction of its specialised niche.

.Gladiolus illyricus

Gladiolus illyricus in Spain. Photography: A.J.Lockton

Further Work 

More studies along the lines of Buchanan’s genetics work is needed to determine if the British Wild Gladiolus is indeed a distinct taxonomic entity. Ecological studies into its niche in the New Forest could help to shed light on its nativeness, or otherwise, and its value to conservation. Any records of this species outside the New Forest are particularly interesting, as there is some doubt about whether casuals are of the taxon or not. Any such record needs to be fully validated and backed up by photographs and - if it is legal and responsible to collect - voucher specimens.

Gladiolus illyricus

Gladiolus illyricus in New Forest. Photography: F.J. Rumsey

References 
  • Brewis, A., Bowman, R.P. & Rose, F. 1996. The Flora of Hampshire. Harley Books. Buchanan, A. (c. 2007) The Taxonomic Status of Gladiolus illyricus (Iridaceae) in Britain. MSc thesis, Imperial College, London.
  • Lockton, A. 2006. European gladioli. BSBI Recorder 10, 11-13.

Thanks to Fred Rumsey, and to Aeron Buchanan for the use of his MSc dissertation.

 

Citation 
Lockton, A.J. (date accessed). Species account: Gladiolus illyricus. Botanical Society of the British isles, www.bsbi.org.uk

Festuca altissima

Taxonomy 

Festuca altissima All. Wood Fescue

Chromosome No.: 2n = 14 (several authors). A single report of 2n = 42 by Stahlin (1929) probably arose as a result of confusion with Schedonorus arundinaceus or S. giganteus.

Festuca altissima

Photography: A.J. Richards

Identification 

A rather isolated species, placed by itself in section Drymanthele, and not known to hybridise. The other broad-leaved fescues form clasping auricles at the top of the sheath, and have 5-nerved lemmas (often appearing 3-nerved) which are often awned. In F. altissima the lemmas are 3-nerved, although only the central nerve is conspicuous so that they appear 1-nerved.

As this scarce and vanishing species typically grows on inaccessible cliffs in ravines, these technical distinctions are not often available for examination, and this is a plant which is usually identified by its ‘jizz’. Usually it is helpful to examine suitable sites with a good pair of binoculars. Typically, a site is examined at a distance from the other side of the ravine, a bridge or from the opposite side of the river. Plants are gregarious and form regular many-leaved tussocks, bearing uniform flat rather dark somewhat shiny evergreen leaves up to 50 cm long which arch upwards at an angle of about 45 degrees and only droop slightly at the apex. The persistent sheaths are rather dark brown and lend a purplish hue to the base of the tussock. The leaves are about 10 mm wide, and so are narrower than Luzula sylvatica, but broader than Deschampsia cespitosa which are almost invariably associates. At a distance, other confusion species can include Schedonorus (Festuca) giganteus and Bromus ramosus, but they do not form many-leaved regular tussocks to the same extent, are a paler green with grooved leaves and the leaves droop more; and Brachypodium sylvaticum which is also paler and more drooping, and is a smaller plant. If flowering panicles are present on F. altissima, they are characteristically narrow and tall, with erect branches (spreading or drooping branches in all confusion species), and it is usually possible to note that awns are absent, thus ruling out S. giganteus. With practise, this species can be accurately identified with binoculars at a range of up to 100 m at any time of year.

Festuca altissima

Photography: A.J. Richards

Distribution 

Although F. altissima occurs southwards to northern Spain and northern Greece, it is restricted to montane areas with humid climates and reliable summer rainfall. It occurs eastwards to the Urals, but in Scandinavia the distribution is distinctly Atlantic (Hulten 1950).

BSBI Hectad Map 

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

Status 
  • Origin: native.
  • Rarity: not rare in Britain or Ireland.
  • Threat: both Perring (in Preston et al. 2002) and Cope & Gray (2009) are optimistic about the present status, pointing out that it was seriously under-recorded for Perring & Walters (1962). To say that the regions in which it occurs were ‘not well recorded’ is disingenuous. Rather, some botanists have since learnt which habitats it grows in and how to recognise it from a distance, information which has yet to appear in an identification guide. My experience is largely restricted to Northumberland and Durham, where this is a rare and threatened species which is represented by very few populations. Most of these are represented by a very few individuals, some populations have disappeared completely, and all probably contain fewer individuals than when first recorded. Although now known from more than 100 hectads in Britain, twice as many as in Perring & Walters (1962), I believe this is a species threatened by climate change, and populations should be monitored in areas where it is more widespread such as the Lake District and the Trossachs, to see if populations remain stable.
  • Conservation: listed as an axiophyte in all counties that have it.
Ecology 

Nearly all sites are in old, often largely undisturbed primary woodland. Restricted to difficult terrain, which has resulted in restricted forest clearance. Consequently, most habitats are not threatened. However, F. altissima almost invariably coexists with Luzula sylvatica which tends to be much more successful, aggressive and catholic in its requirements and appears to outcompete it. I suspect that warmer summers have allowed the latter to disperse into and survive in niches previously occupied by the grass. Typically inhabits horizontal joints in near vertical cliffs above rivers, under deciduous trees in partial or complete, often deep, shade. Mostly commonly found on rather calcareous sandstones. Associated species suggest that absence from large areas of apparently suitable habitat can be explained by the low carbonate content of the sandstone, giving rise to soils of too acidic a reaction. Also grows in hard limestone and dolerite. Invariably occurs within 50 m of water, and is often found only just above flood level and not higher up the cliff. Undoubtedly needs continuous levels of high humidity at all times, and the observation in Cope & Gray (2009) that it is shallow-rooted may explain its very stringent habitat requirements, and vulnerability to competition, as well as dislodging. Subsidiary habitats include vegetated talus below cliffs if above flood level, and wooded limestone pavement. To associated species listed in Cope & Gray (Galium odoratum, Luzula sylvatica, Melica spp., Polystichum spp., Sanicula europaea) can be added Dryopteris dilatata, D. filix-mas, Deschampsia cespitosa, Bromus ramosus, Schedonorus giganteus and Brachypodium sylvaticum. Typically the woodland (NVC W8) is dominated by Quercus spp., but may include Fraxinus excelsior and the cliff scrubby Ulmus glabra and Corylus avellana. In many sites it flowers rarely, or few inflorescences are produced. It suffers from the usual problems experienced by chasmophytes, so that establishment may depend upon seeds being caught in spiders webs, and seedlings are unusual. Most populations consist of mature tussocks which may be a considerable age. Consequently, attrition from competition and erosion may exceed the regenerative power of the population.

Further Work 

Future work should include base-line population surveys with regular follows-ups to determine whether populations are stable.

References 
  • Hulten E. 1950. Atlas of the distribution of vascular plants in NW Europe. Kartografiska Institut, Stockholm.
  • Stahlin A. 1929. Morphologische und cytologische untersuchungen an Gramineen. Pflanzenbau 1: 330-397
Citation 
Richards, A.J. (date accessed). Species account: Festuca altissima. Botanical Society of the British isles, www.bsbi.org.uk.

Ceratocapnos claviculata

Taxonomy 

There is no confusion over the identity of Climbing Corydalis, but it has suffered somewhat from nomenclatural issues. The correct name is Ceratocapnos claviculata (L.) Lidén but it is perhaps better known in Britain as Corydalis claviculata (L.) DC. (e.g. in Clapham, Tutin & Moore 1989) and it has also previously been known as Capnoides claviculata (L.) Kuntze. It is the only British member of the genus Ceratocapnos (Stace 1997).

Chromosome No. 2n =32 (Stace 2010).

Ceratocapnos claviculata

Photography A.J.Lockton

Distribution 

It is a European endemic, according to the map produced by GBIF, where it is largely restricted to the Atlantic fringe. The Maps Scheme map shows it occurs almost throughout Britain except Orkney, Shetland and the Outer Hebrides, and it is rare in Ireland, only occurring in the south-east. It is therefore an oceanic species that, unusually, avoids the most oceanic parts of the British Isles.

The New Atlas (Preston, Pearman & Dines 2002) gives it a Change Index of +0.57, but the author of the account, P.J. Wilson, states that its range has not changed and the apparent increase is a consequence of better recording.

However, Nicole Voss of Justus-Liebig-Universität, Gießen (see Further Work) describes it as having spread significantly in Europe in recent decades, and is investigating the effects of its spread.

Ceratocapnos claviculata

Photography A.J.Lockton

BSBI Hectad Map 

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

Status 
  • Origin: native.
  • Rarity: although it is not a rare plant in Britain this is a plant for which we have a large proportion of the global population, so (like bluebell) it is an important species here. It is very rare in Ireland.
  • Threat: in Britain it is currently listed as being of ‘Least Concern’ (Cheffings & Farrell 2005).
  • Conservation: there appear to be no conservation initiatives for it. It should arguably be at least passively monitored, from the point of view of conservation of genetic resources. Almost all counties that have axiophyte lists have included it, which suggests that it is of considerable importance for nature conservation.
Ecology 

Rodwell (1991) lists only W10 Quercus robur and W16 Quercus petraea woodland types for this species. Ecological accounts for it are difficult to find. One of the most authoritative available is given by Sinker et al. (1985) in their account of it in Shropshire: ‘Open woodland and edges of dry peat mosses, persisting in grassland on previously wooded sites, on dry to damp sandy or peaty soils, PN poor base poor, acid, usually sheltered and half shaded to shaded but tolerates some exposure to sun. Poor competitor but sometimes abundant in disturbed parts of recently cleared plantations or woods, scrambling over tree stumps.’

Further Work 

It evidently occurs in more NVC communities than those listed by Rodwell. Whether it is indeed increasing in Britain within the limits of its range is a question that might be difficult to answer. Another potentially interesting question is how its ecology differs towards the edges of its range.

Nicole Voss is appealing for information on Ceratocapnos claviculata throughout Europe, seeking phytosociological data and requesting specimens for genetic analysis.

References 
  • Clapham, A.R., Tutin, T.G., & Moore, D.M. 1989. Flora of the British Isles, 3rd ed. Cambridge University Press.
  • Sinker, C.A., Packham, J.R., Trueman, I.C., Oswald, P.H., Perring, F.H. & Prestwood, W.V. 1985. Ecological Flora of the Shropshire Region. Shropshire Trust for Nature Conservation, Shrewsbury.
Citation 
Voss, N. (date accessed). Species account: Ceratocapnos claviculata. Botanical Society of the British Isles. www.bsbi.org.uk.

Carex elongata

Taxonomy 

The name Carex elongata L., Elongated Sedge, is accepted by all authorities.

Chromosome No.: 2n = 56 (Stace 2010).

Carex elongata

Photograph: A.J. Lockton

Distribution 

C. elongata is widely but sparsely distributed throughout the British Isles. In Scarce Plants (Stewart, Pearman & Preston 1994) Dick David described how it had disappeared from canals and ponds in the Manchester area and showed a fairly dramatic decline. In the New Atlas (Preston, Pearman & Dines 2002) it is shown as slightly increasing. However, the maps do seem to show a long-term decline that may well be continuing.

BSBI Hectad Map 

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

Status 
  • Origin: native.
  • Rarity: Nationally Scarce in Britain (Stewart, Pearman & Preston 1994); similarly scarce in Ireland.
  • Threat: listed as ‘Least Concern’ (Cheffings & Farrell 2005).
  • Conservation: it is universally regarded as an axiophyte, usually as an indicator of ancient woodland. In Hampshire and Surrey, populations have been boosted by apparently successful reintroductions (data from the TPDB).
Ecology 

The ecology of C. elongata is perhaps its most interesting attribute. It is most typically a plant of W5 Alnus glutinosa woodland on scrubbed-over mires that are inundated by surface water. Jermy et al. (2007) say it also occurs in W2 Salix-Betula woodland and C.R. Hall (pers. comm.) considers that it grows in W6 Alnus glutinosa woodland in Hampshire. David (1994) describes how it often occurs on floating wood, and Mallabar (1998) takes this one step further, suggesting that seeds tend to germinate on rotting wood, due to some association that has not yet been defined. This might explain why David (op. cit.) considered seeds to have low viability. In the past, C. elongata was found on the rotting wooden piles of canals, but it appears to have completely gone from canals now as wood is no longer used in their construction. C. elongata populations fluctuate enormously in size, being most successful in late-successional sites as they start to dry out. Hencott Pool in Shropshire was considered one of the best sites for it in the 1980s, with hundreds of plants, but it had almost gone from there twenty years later (Lockton & Whild 2003) as the pool dried out and the canopy closed. Hill et al. (1999) give it an Ellenberg L value of 5, which is for half shade, and it presumably cannot thrive under a very dense woodland canopy.

Further Work 

More research into its highly specialised ecological niche would be worthwhile, including a more detailed examination of its vegetation communities. A close watch should be kept on its distribution to find out whether it is in fact declining.

References 
  • David, R.W. 1994. Carex elongata. In: Scarce Plants (Stewart, Pearman & Preston).
  • Jermy, C., Simpson, D., Foley, M. & Porter, M. 2007. Sedges of the British Isles, 3rd ed. Botanical Society of the British Isles, London.
  • Lockton, A.J. & Whild, S.J. 2003. A botanical survey of Hencott Pool. Whild Associates report to English Nature, Shrewsbury.
  • Mallabar, J. 1998. Habitat status and niche requirements of Carex elongata L. in Britain. MSc dissertation, School of Biological Sciences, University of Birmingham.
Citation 
Lockton, A.J. (Date accessed). Species account: Carex elongata. Botanical Society of the British Isles, www.bsbi.org.uk.

Who's online

There are currently 0 users and 3 guests online.