Rosa canina (Dog-rose) identification.

Rosa canina (Dog-rose) identification.

With R.canina agg. being split into  three species, R. canina, R. corymbifera and R. squarrosa I thought I would take a few photos of a 'perfect'  R. canina (or R. canina stricto sensu) in Cambridgeshire.  

The main problem is finding an example of R. canina s.s. which conforms to the new handbook description and does not show features of the two northern dog-roses or R. corymbifera and R. squarrosa.

I don't want an example which has:-

Glaucous coloured underside to leaves or folded leaves.

Zig zag stems.

Stems that show a red colour.

Short pedicels suggesting hybrid with Northern Dog-rose.

Short pedicels with large bracts that obscure the pedicels. R. canina s.s. should have pedicel length in the range 1-2.5cm whereas northern dog-roses should be in range 0.5-1cm and the hybrids could be anywhere, but I would like an example with some pedicels at least 1cm. 

Large hips especially if round/spherical.

R. canina s.s. should have a 'temple dome' shaped uni-serrate margin to the leaves without any glands, so NO glands.

Soft hairs or glands on the petiole/rachis. 

Odd looking prickles.

Leaf stipule glands that stay on and are round rather than slightly elongated.

That's probably enough features I don't want, but there are probably more. This proved quite hard as most R. canina potential plants failed, for one reason or another. 

Pedicel has no glands. A key feature of the Dog-roses.

My selected potential R. canina growing in Wicken Fen.

Erect and arching stems.

Pedicel has no glands and is over 1cm, not enclosed by bract.

Sepal is pinnate and should not have too many secondary side projections or too many glands to be acceptable for R. canina.   Sepals of the three dog-roses R. canina, R squarrosa and R. corymbifera become reflexed as the hip ripens and fall off early.   Sepals of R. squarrosa might have more glands on the tips of the pinnate side projections.

Orifice is narrow and the disc is conical. A conical disc is very common in Cambridgeshire for R. canina.  Sometimes this conical disc is given the name R. canina var. spuria according to the new handbook. The orifice is deep and has vertical groves from forming around the style. 

Next photo shows the sepals have already become reflexed even though flowering has only just finished and the hips have not started to turn red. The rate that sepals move seems very variable even on a single plant but the fact that on this plant they have reflexed early is a good sign for R. canina.

Next the leaves. Green on top and flat not folded.

The leaf has several important features to consider. 

Uniserrate margin with hydathodes only, no glands.

Underside just a paler green. Margin is uniserrate, no glands.

Petiole and rachis has no glands or hairs on. A key feature.


Leaf stipule.

The leaf stipule glands are falling off and the remaining ones are elongated in shape which conforms to Tony O'Mahony's discovery that roses in the subsection caninae ( Dog-roses) have these features. See previous blog that covers this subject. I always pick a new leaf from a new shoot for this test if possible.

Prickles.

It often surprises me the variation in prickles on a single bush but the above conform to what I would expect for a R. canina, in that they have a broad base and are variably hooked. I have seen quite a few potential plants of R. canina locally, near Swavesey, that have very straight prickles which don't look right and suggest some introgression, but what with, is a puzzle.

Conclusion.

The above photos I think are a good example of what a Rosa canina should look like at the post flowering stage. The well known problem that every Dog-rose bush looks slightly different, so you have to accept quite a lot of variation but where to draw the line and decide it no longer fits the 'perfect' R. canina is a challenge.  Some introgression is allowed, otherwise very few roses would be identified beyond R. canina Agg.

Finding a good example of R. canina was quite difficult as most plants have features that could indicate more than a little introgression with another, now separated species, either R. corymbifera, R. squarrosa or more frequently R. vosagiaca / R. caesia. Hybrids with species outside the Sub-group caninae also occur and another rose bush at Wicken Fen seemed to some features of R. rubiginosa with large glands on the underside of the leaves and just the odd acicle.

The above is a personal view but based on the new BSBI Rose handbook which was published in late 2025.

Peter Leonard

Cottenham, Cambridgeshire.

July 2026

An example of a plant that didn't make the grade.

There above photo of a rose near Longstanton, shows a potential R. canina but the sepals are not reflexing at all and are starting to fall off. This suggests some introgression with either R. caesia or R. vosagiaca ( Northern Dog Roses) and the leaves were also folded more than I would have liked. All other features of this bush aligned with R. canina and the observation than no hairs were present on the leaf might suggest this plant has a tiny amount of R. vosagiaca in it. R. canina x R. vosagiaca = R. xsubcanina.

Rosa squarrosa ( Glandular Dog-rose) in Cambridgeshire

Rosa squarrosa ( Glandular Dog-rose) in Cambridgeshire.

Now that Dog Rose R. canina aggregate  has been split into three separate species and documented in a new BSBI handbook, Wild Roses of Great Britain and Ireland by Roger Maskew and Gareth Knass, BSBI Handbook no 26, I thought I would try and find a Rosa squarrosa to photograph.

Glandular Dog-rose, R. squarrosa, 17th June 26, Cambridgeshire.

Previously R. squarrosa was regarded as a subspecies of R. canina under the sub-species group Dumales.

 R. canina agg. is now split into three species ( Canina, corymbifera and squarrosa ). This creates the complication of defining each of the hybrids between them and also the Northern Dog-rose,  which has also been split into R. vosagiaca (Glaucous Dog-rose)and R. caesia (Northern Dog-rose). 

This particular plant was surprisingly green but I would not assume this is a characteristic of squarrosa or any other dog-rose.

The first characteristic feature I check is the pedicel ( flower stalk below the hypanthium (hip)) as dog- roses should have a clean stalk without any glands, which is the case here. 

The sepals are pinnate with a few glands. They are reflexed even at this early post flower stage, which  fits with squarrosa, canina and corymbifera. At this early stage, just after flowering, sepals are moving from their flowering position of being out and downward, pointing at about 45 degrees. Timing of the sepal movement seems to be quite variable and sepal position is normally looked at later when the hips have turned red.   In this particular example the sepals have moved to a reflexed position quickly.

Hypanthium, sepals, and pedicels. Group of two hips on long pedicels.

The photo below shows the sepal with pinnate lobes, which have glandular tipped side projections and also a leaflike extension. Despite R. squarrosa being glabrous (no hairs), hairs are allowed on the sepals and on the stigma cluster.

The photo below shows the disc and stigma/styles. The disc is quite conical which is common in Rosa canina and I assume can often occur in squarrosa. The stigma covers about half the conical disc and has some short hairs visible.

Other characteristics are that, the pedicels were between 1 to 2cm against a handbook range of 0.8-2cm, so that's OK, although I don't find pedicel length reliable as it seems to vary a lot even on the same bush. Extremely short or long pedicels are worth noting.

  The orifice was small at about or less than a 1/5th of the disc diameter. Note the long thin hole that the stigma threads pass through and its gradual opening out into the hip capsule. One of the few criticisms of the old handbook was the drawing of the R. canina sectioned hip by Margaret Gold, which showed a rapidly opening orifice inside. This is not typical of R. canina and I suspect the sample  she was given  may have satisfied the characteristics of R. canina, but had some Northern Dog-rose in it. Overall her drawings were really very good and in some cases better than the photos used in the new handbook.

Cut hypanthium showing orifice and domed disc. R. squarrosa

An example of an atypical orifice suggesting hybrid with Northern Dog-rose or just a variation due to the flat disc?.

Also a very round shape to the hypanthium/hip.  Hip shape is variable according to the new handbook including spherical, although in Cambridgeshire I speculate that a spherical hip may suggest some hybrid influence.  Hard to prove though.

An example of a canina type orifice with a almost flat disc.

Next up is to look at a leaf.

Leaflets 5-7 and broadly ovate to ovate-lanceolate, acute or subacute, rounded at base, according to the new handbook.     The leaves shown below are not drawn out to an attenuated tip, are well spaced and are hairless, as required, to be conforming with squarrosa. Tony O'Mahony, a rose expert from Ireland, has noted that leaf shape is highly variable in R. canina and this is probably true for R. squarrosa. 

'This field study revealed that the only common denominators between the various R. canina populations, was that they all displayed glabrous, non-glandular foliage.

Yet, in stark contrast to these two points of uniformity, was the remarkable fact that the

leaves of this species proved bewilderingly polymorphic, my observations recording

considerable morphological plasticity in leaflet shape, dimensions, toothing, texture and

colour – not only between populations, but often between individual, adjacent bushes in

hedgebanks and hedgerows. Moreover, no correlation could be found between these leaf

forms and other features of these bushes. '

This insight from Tony O'Mahony is really useful and it's pity that the new handbook does not highlight such information.

R. squarrosa.

Another important feature I look at, is the leaf stipule glands, a feature not mentioned in the new handbook, but which has been found to be really important. See previous blog on this feature, Identification of Roses, Leaf Stipules. 

Leaf stipule showing dense glands still present and mainly round in shape with only the occasional elongated gland. This is a bit odd as the dog-roses should have glands that fall off quickly and are elongated in shape. These are staying on and are mainly round balls, not the elongated shape. When confronted with a feature that does not quite fit, a larger sample should be looked at, ideally from more than one major stem.  

The petiole (leaf stem) is also shown in this photo and shows a lot of stalked glandular protrusions. The glandular protrusions being a key feature of R. squarrosa. Note also no soft hairs.

Next photo is of the rachis which also has lots of stalked red glands. Ignore the fibres brought in by the wind but note the rachis has no soft hairs.

The major feature of R. squarrosa is that it has no hairs (except on the styles and sepals), being glabrous. The stalked glands are not included as hairs.  Below is a photo of the rachis of R. corymbifera showing the dense soft hairs which are its key feature.

   R. corymbifera rachis with dense soft hairs. 

Back to my potential R. squarrosa. Next check leaf margin.

Leaf margin showing bi-serrate edge with the secondary tips having short stalked and sessile red  round glands. The primary tips have hydathodes which are conical in shape and lack the liquid ball, unlike the round glandular tips on the secondary tips. Note the hydathodes have veins running to them.

According to the new handbook R. squarrosa can have either bi-serrate to multi-serrate margins. 

The underside of the leaf is glabrous, not a hair to be seen even on the midrib, just the occasional stalked red gland.

Prickles of R. squarrosa.

Conclusion.

This particular plant matches the expected features of what a Rosa squarrosa should look like, with the only aberrant feature being the round, more permanent glands on the stipules. This does suggest a slight introgression in the past with a Sweet Briar or a Downy Rose but no other sign of this was apparent. The bright green colour of the leaves was also unusual. 

 I think this plant could be regarded as belonging to the species as defined by the new handbook and we don't need to investigate further hybrids. A small amount of introgression is acceptable. The most common hybrid would be with Northern Dog-rose now split into R. caesia and R. vosagiaca.

The hybrid with either of the Northern Dog-roses would tend to show reddish stems, which were completely lacking in the plant described above. The new handbook says R. squarrosa, 'often strongly red-pigmented in open habitats in late summer' so the red stems appear to be an unreliable feature?

The influence of either caesia or vosagiaca would tend to have groups of hips (3-4)  on unusually short pedicels with large bracts that obscure the pedicels and large hips, densely hairy styles forming a dome-shaped head and blue-green back to the leaflets.

The plant above had 1-2(3) hips with longer pedicels. The pedicels were towards the 2cm range and the bracts did not cover them.  Before these splits, R. canina group ( canina agg.) were the most common rose in Cambridgeshire followed by hybrids with the Northern Dog-rose, despite the fact that Northern Dog-roses do not occur this far south, being limited to north of a line between the Severn Estuary and the Wash. On recent field trips I have found the Northern dog-rose hybrids to be very common but working out what are the parents are is not easy. Hybrids are fertile and backcross.

Hopefully these photos will encourage the purchase of the new rose handbook. It's not perfect but is a major advance. It is photo based and covers a wide range of rose species and hybrids. The increase in the number of hybrids will be quite a challenge.

 Although the conventional wisdom suggests that roses should only be examined in late summer based on the hip being fully formed and sepal position/falling off being critical, I think a lot can be done when roses are in flower. Sepal position changes as the hips ripen and this seems to have very variable timing.

Difficult plants may often require a second visit to aid final identification. 

Finally I have been caught out several times by two different species growing together with intertwined stems which caused confusion, until that was pointed out by someone more expert than I.

Peter Leonard

Cambridgeshire

June 2026

See also, previous blog on Identification of Roses, Leaf Stipules.

Identification of Roses, Leaf stipules.

Identification of Wild Roses, Leaf stipules. Based on new research by Tony O'Mahony.

Leaf of Rosa agrestis showing stipule.

In a recent major article by Tony O'Mahony in the Irish BSBI bulletin (ref 1), he found that Dog Roses in the subsection Caninae ( Canina, caesia, squarrosa, corymbifera and stylosa.), leaf stipules have a different gland type to that of other groups ( Rubiginosa and Vestitae.). R. tomentella is regarded as having its own sub-section although being close to the caninae section.

  His article covers many other new features but here, I thought I would illustrate the stipule gland feature, as it has been found to work well in Cambridgshire.

Warning. Dog Roses are a difficult group with features that not easy to separate into what are now regarded as 'species'. Recently British and European Dog Rose species have been aligned ( ref. 2) resulting in R. canina being split into three species, R. canina, R. corymbifera and R. squarrosa. Also the Northern Dog Rose R. caesia has been split into R. caesia and R. dumalis/vosagiaca. Unfortunately an updated BSBI Handbook has not appeared yet although I hear one is being written, so the BSBI Handbook No7 by Graham and Primavesi (ref. 3)is still the best source of information. Good though it is, it is now showing its age. New features that Tony O'Mahony has found are not covered.

The Species Problem.  Roses as a group do not fit into neat species. What now have been decided to be  'species' are hybrids that arose in the distant past from unknown parents and became stable and spread as ice ages came and went. Although 'stable' the evolutional splits and regroupings never reached the stage where different 'species' could not freely hybridise. In more recent times, although these old established 'species' are widespread, any local groupings of different 'species' will hybridise and sometimes produce viable offspring. The problem is particularly bad with the Group Caninae (Dog Roses) with their strange unbalanced combining of the parents genes (canina-type meiosis) plus frequent hybridisation. Reticulate lineages in evolution cause problems as most genetic analysis  assumes a branching tree of life to generate the relationships between species (Phenograms).  

As an amateur botanist without any formal training, I try and look at as many features of a rose as I can cope with and see if they all fit the somewhat basic descriptions in the handbook. Some plants fit well but many have aberrant features, which indicate they are not quite right for a perfect example of that species. The additional feature of stipule glands can help to confirm a good fit but can also show a Dog rose which was thought to be a straight forward R. canina but is in fact hiding some genes from, say a Sweet Briar. The stipule glands are however a useful identification tool to add to the range of feature that should be considered.

The New Feature.

Tony O'Mahony spotted that Dog Roses ( Subgroup Caninae) have stipule glands that are not round but elongated and also are feebly attached and therefore quickly detach leaving older leaves to have none left on the margin. Often these glands are well spaced on the margin and forward pointing.

Subsections Vestige ( R. mollis, sherardii, tomentosa, villosa) and Rubiginosa ( R. agrestis, micrantha, rubiginosa) have have stipule margin glands on stout stipes ( stalks) , the stipes are patent and permanently attached. Each gland is round in shape and when fresh, full of volatile oils, often red in colour. Strangely they often have a larger one, then a smaller, then a larger one along the margin and can be quite dense.

A) Dog Roses.

Rosa canina, close up of elongated glands on stipule margin near the tip.

Rosa canina. Rampton 31Jul23. Elongated glands and also missing ones which have got detached.

Note that the elongated glands on the stipule margin are different from the petiole glands (leaf stalk) which are stalked and round tipped.

R. corymbifera. Even when dried out the glandular tips of this Dog rose are clearly elongated and in this example, on forward pointing tips. 27th July 23. Cambridgeshire.

Dog Rose. R. canina . 7Jun23 Devils Ditch, Cambridgeshire

The photo above shows elongated glands which are mainly forward pointing and also sections of the stipule margin that have lost their glands even at this time in June. 

R. canina with possibly some caesia in it. Allendale, 21Jul23 

Above photo included to give a bit more geographic range ( Northumberland) to these photos. A dog rose that had mixed features of canina and caesia and therefore regarded as a hybrid.   It does show forward pointing glands, which even though dried are elongated, although the smaller ones do appear to be more rounded. It is possible that this particular rose has a more complex history and is not 100% a dog rose. It would seem that the Dog Roses can also have the big, small, big gland pattern but what that means is unclear.

Another canina/caesia hybrid, Fen Drayton, Cambridgeshire, 

Clearly elongated glands but not as forward pointing as one might expect. Interestingly the larger elongated glands are interspersed with smaller sessile glands. This does seem to occur in some examples of Dog Rose.

R. stylosa. slightly dried but still elongated and forward pointing.
25 Jul23 Comberton , Cambridgeshire.

It is interesting that although R. stylosa is held within the Subsection Caninae it is often regarded as not being a 'Dog Rose' yet it still displays the elongated forward pointing glands. It does show some variation in size with the big, small, big pattern, seen in the non 'Dog rose' groups but also in some 'Dog Roses'. 

B) Non Dog Roses.

R. rubiginosa. Fresh round glands on short stalks, patent not pointing forward.
25th July 23 Comberton, Cambridgeshire.

This example shows the big, small, big alternate sized glands, the smaller being sessile.

R. sherardii, 23 Jul 23. A11 junction near Duxford.

 A non Dog Rose in that rounded glands, not forward pointing, dense along margin and displaying the big, small, big pattern. 

R. micrantha,  Buff Wood, Cambridgeshire.

Again the round glandular tips to the stipule margin. Also large and small and evenly spaced.

Rosa mollis,  Grosmont, North Yorkshire, 16 Jul 2025

Conclusion.

It would appear that there is a difference between Dog roses Sub-section Caninae and non Dog roses when it comes to stipule gland shape. The forward pointing and big, small, big features seem more random. What works in County Cork seems to work well here in Cambridgeshire. 

There are problems in that the Dog roses have often lost all their  glands but usually it is possible to find a new leaf on a late non flowering shoot which may have glands left. The gland shape can be seen with a X10 or X15 magnifier.  The paper by Tony O'Mahony is linked below and he has to be congratulated on highlighting this new feature.  

Ref 1,  Irish BSBI News No 33 Page 5  by Tony O'Mahony

https://bsbi.org/wp-content/uploads/dlm_uploads/2023/05/IBN-2023-V2.pdf

Ref 2, 

Dog-roses (Rosa sect. Caninae): towards a consensus taxonomy, Piet Bakker, Bert Maes, Roger Maskew, Clive Stace.

https://britishandirishbotany.org/index.php/bib/article/view/10

Ref 3, Roses of Great Britain and Ireland by G.G. Graham and A.L. Primavesi BSBI Handbook No 7 1993

Peter Leonard

Rampton, Cambridgeshire

10 Aug 2023

Update 29th August 2023.

Roses are never going to be easy and today in Hayley Wood we found a rose that would appear to be a Dog Rose, with no glands on the pedicle and might fit the group Dumales/ R. squarrosa, but had round glands on the leaf stipule. This and another similar plant nearby seems to break the rule and can only wonder what this means in terms of its parents. This combination of Dog Rose features and round glands on the leaf stipule is not common, as several hundred roses up to this point had conformed to the suggestions by Tony O'Mahony. I can only assume this is down to a more complex history with some hybridisation to a non-caninia type rose. When looked at these plants did have a some slight differences to the other canina type roses in the wood. A few photos follow.

Dog Rose, R. squarrosa Hayley Wood. 29th Aug 23

A rule breaking example of a Dog Rose showing round stipule glands.

Dog Rose , Hayley Wood , with round stipule glands. The hip is more rounded than typical Dog Roses found in Hayley Wood which might indicate a more complex history. 

Dog Rose at Hayley Wood, with round stipules glands. The orifice is narrow as expected and the disc almost flat to slightly convex. Many of the Dog roses in Hayley Wood have a much more convex conical disc.

It would be good practice to go back and have another look at these plants when in flower, as the more features you look at the better.

Rosa agrestis. Small-leaved Rose in Cambridgeshire.

 Rosa agrestis Small-leaved Rose in Cambridgeshire.

In June 2020 Joe Sharman (of Monksilver Nursery at Cottenham)  brought Alan Leslie ( author of Flora of Cambridgeshire) a specimen of an unusual rose he had collected  from near Knapwell Wood. Alan recognised it as a probable R. agrestis and this was confirmed by a visit to the site and subsequent confirmation by the BSBI rose expert Roger Maskew. This was the first record for Cambridgeshire. I had been attempting to take photos of all the wild roses found in Cambridgeshire, so this proved an added bonus as this was not a species I had considered as a remote possibility. There is only one other dot on the BSBI map in East Anglia and that is near Norwich.

R. agrestis is a very rare rose with just a scattering of records in Southern Britain and slightly more in the centre of Ireland.

This blog contains some photographs of the excellent find by Joe and Alan.

R. agrestis belongs in the Section Caninae because it has the peculiar canina meiosis where four fifths of the inheritable characteristics come from the seed parent. All roses in the section caninae are all unbalanced polyploids. R. agrestis is in sub-section Rubigineae with R. micrantha and R. rubiginosa.   

R. agrestis Knapwell Wood, 15th June 2020

At first sight the flower could be passed over as just another Dog Rose.

R. agrestis.

The stigma cluster is quite large nearly covering the disc and with few hairs if any. The disc is slightly convex. Again this could be within the variation of a Dog Rose R.canina.

R. agrestis, 15th June 2020 Sepals and pedicel.

The pedicel (stalk just below the flower and hypanthium) has no glandular hairs being clean, again just like a Dog Rose R. canina. The sepals have an upper surface covered in cobwebby hairs which is a feature shared with many other roses. The sepals are long and pinnate with edges showing the red tips of the glandular hairs. Sepals are reflexed at flowering stage. Again there is nothing here to separate it from a Dog Rose R. canina although the number of red tipped glandular very stalked hairs on the sepals is a bit unusual for a R. canina.

R. agrestis Underside of leaf. 15th June 2020

Leaflet shape has narrow base (cuneate) which is not normal in Dog Rose and the stem between the leaflets ( petiole and rachis) are covered in stalked glandular hairs and no simple hairs. Hard to see in this photo but the leaflets have scattered clear glands all over the lower surface. Time to take a more detailed look as these glands are not consistent with a Dog Rose.

R. agrestis Underside of leaflet. 15thJune2020

The underside of the leaflet is covered with clear stalked glandular hairs and although there is some variation in the size of these glandular tips they are in the range 0.1-0.12 mm diameter for the larger, which is similar to those seen on R. rubiginosa and R. micrantha.

R. agrestis 22nd Aug 2020, Leaf upper-side somewhat shiny. The lower leaflets are often smaller and reflexed.

R. agrestis Leaf upper side, new growth May 2021

R. agrestis Leaflet edge showing glandular edge. 22th Aug 2020

A close view of the leaflet edge shows a uniserrate edge with glandular hairs on both sides of the teeth which give it a multi-serrate look. The teeth tips have red hydathodes which are different to the glandular hairs in that they are solid and hard and pointed, not rounded. The glandular hairs are not really forming on distinct secondary-tips. Exact shape of leaflet edge does change depending on what part of the leaflet you look at and sometimes the glandular hairs do sit on secondary tips, as shown below on a new leaflet taken in May 2021.

New growth, May 2021. Multiserrate edge.

R. agrestis Stipule at base of leaf. 15th Jun 2020

Stipule is quite narrow with stalked glandular hairs on the edge and also some on lower surface. The glandular hairs on the leaf stem (petiole) are often on a short stalk and the rachis and petiole lack any white simple hairs. 

R. agrestis 15th Jun 2020. Stipule and young prickles.

R agrestis. 15th Jun 2020 Base of terminal leaflet.

Not all leaflets will be as extreme as this example but the narrow cuneate base is a key feature of R. agrestis. Note also the stalked glandular hairs on the rachis with no simple white hairs.

A new word to learn....

R. agrestis. 15th Jun 2020. Leaflet veins highlighted to show semi-craspedodromus pattern.

One of the important features in separating roses in the fossil record is the semi-craspedodromus pattern shown in some roses species. This is not a term I had come across before, so had to look it up. 

Although quite subtle and not present in every part of the leaflets, overall these leaflets show this semi-craspedodromus pattern with the loops before the veins make it to the leaflet edges. In a craspedodromus leaf the veins all end up going directly to the leaf margin. Some may split on the way. The semi-craspedodromus venation is present in all the section caninae roses and many others, so it is not a useful ID feature but it would be an interesting find if you found a rose that did not have his feature. An example would be Rosa stellata which has leaves like a gooseberry, but it is not hardy in the UK coming from the deserts of Texas to Arizona. 

Craspedodromus leaf venation      Semi-craspedodromus leaf venation

R.agrestis 15th Jun 2020. Stem prickle.

The BSBI Rose handbook No7 shows the prickles having a very stout base whereas the prickles photographed were a more ordinary shape. However the shape of prickles is quite variable depending on what part of the stem you look at. These prickles are not very hooked.  

R. agrestis 15th Jun 2020 Near Knapwell Wood, Cambridgeshire.

Finally a photo of the largest, possibly the original, plant in this group of about ten plants.

All these section Caninae roses are species derived from hybrids from their past evolution which continue to hybridise now. To identify a rare rose like R. agrestis, I am very grateful that Alan Leslie took a sample and sent it to BSBI rose expert Roger Maskew to be confirmed. 

Peter Leonard

Rampton, Cambridgeshire.

6th May 2021

Ref:- 

 G. G. Graham and A.L. Primavesi.(1993) Roses of Great Britain and Ireland, BSBI handbook No 7 . 

 Leslie, A.C. (2019). Flora of Cambridgeshire. RHS, London.

Postscript. Additional sites seen in 2021.

The nearest agrestis site to Cambridge is at Wymondley near Hitchin. This population was found on the banks of the Wymondley Grid Station back in 1986 and was confirmed by A.L. Primavesi  in 1994.  Alan and I visited this site on 12th July 2021 and a large number of bushes was found. They showed the same key features as the Knapwell plants but had a more greyish leaf colour.  

Wymondley Grid Station  Hertfordshire. 12th July 2021
Note the rose in the picture was not identified as it was inside a perimeter fence.

R. agrestis Wymondley Grid Station 12th July 2021

Leaflet shape showing pointed apex and well spaced leaflets. Petiole and rachis showing lots of glandular hairs.

R. agrestis Wymondley Grid Station 12th July 2021

The above photo shows the slightly greyish leaflet colour of all the plants at this site.

New Norfolk site.

On 27th July 2021, I visited Snettisham RSPB  reserve in Norfolk to see the Western Sandpiper and having obtained distant views, walked south on the footpath to find two bushes which fitted Rosa agrestis.  A sample was taken and this was later confirmed by Mr Maskew as R. agrestis. First record for West Norfolk.

R. agrestis Snettisham RSPB. 27th July 2021

R. agrestis. 27th July 21. Photo showing smooth pedicel, hypanthium and sepals.

R. agrestis. 27th July 2021. Rachis showing glandular hairs plus some simple hairs.

The observations from these two addition sites is that the Wymondley plants had a greyish look unlike the Knapwell plants; the Snettishham plants had additional simple hairs on the petiole/rachis which the Wymondley and Knapwell plants did not have. One has to conclude that within, what is regarded as a species, there is some variation of quite important features. 

Essex Botany No 13 Autumn 2021 reported six bushes of Rosa agrestis had been found on scrubbing saline pastures on Oozedam Farm at Stanford-le-Hope VC18 growing on mud-flat deposits. 

'It's possible that there is sufficient marine shell material in the mud to provide the calcareous substrate which is supposed to need.'

This is the first record for Essex. It might be worth searching for more coastal sites in East Anglia?

Peter Leonard

23rd Feb 2022

Final update 2023. The Knapwell Wood records, following a search of the area by Alan Leslie has been found to have spread from a planted original plant nearby. It would appear that somewhere is a nursery that is carefully propagating wild roses species for sale and this will contaminate the distribution mapping.