Friday, 2 August 2019

Erodium lebelii vs Erodium cicutarium


A summer project to learn about Geraniums and Storksbills ended up with difficulties separating Common Storksbill ( Erodium cicutarium ) from Sticky Storksbill ( Erodium lebelii ). The nearest place to Cambridge where E. lebelii can be seen is Landguard Point , Felixstowe in Suffolk, so off I went to the coast.

Erodium cicutarum is known to be variable in flower colour, size and amount of glandular hairs so the starting point is what an 'normal' plant looks like.

Common Storksbill with bright pink flowers
1) Common Storksbill   (Erodium cicutauium) ( inland plant)
Common Storksbill leaf with non-glandular hairs.



The sepals are pale with green strips. Occasionally plants have been found with very short sepal tips.

Short sepal tip 24th June 2019 Science Park, Cambridge

Next example of variation is some plants have white flowers.

Note almost white stigma, 24th June 2019, Science Park. 
Hairs can be very useful in the identification of Geranium and Storksbills and are normally consistent, however the Common Storksbill is variably hairy. The flower stem can have flattened hairs , short and long upright non-glandular hairs plus upright glandular hairs. Glandular hairs are quite common on the flower stems and are often the dominant type . Plants with glandular hairs on the stems, often have white slightly curved non-glandular hairs on their leaves.

E. cicutarium leaf showing hairs, 18th June 2019, Devils Ditch.

2) Coastal variations of Erodium cicutarium.

The first impression of the Storksbills at Landguard was there were very few plants that looked like the normal inland deep pink flowered type. Most had smaller flowers of a variable paler colour and some white flowered plants, were also present.
The warning first sentence from the Hybrid Flora came into mind ' Small-flowered densely glandular maritime variants of E. cicutarium are often mis-determined as E.lebelii, but the only reliable distinction lies in the mericarp morphology'.  This was backed up by the statement in Harrap's Wild Flowers, ' Identification must be confirmed by examination of the fruits'.  Mericarp is the seed case which is attached to a long beak.  Five beaks make up the storksbill.

E. cicutarium    Mericarp seed case with hairs enclosing the dark brown seed.

The mericarp, a hairy case containing the seed,  attached to the beak. 
The critical feature is the shape of the pit where the mericarp attaches to the beak and whether the hairs over-reach the pit.

Following the Harrap's Wild Flowers advice I went looking for plants with more densely glandular hairs ( often picking up sand) and more greyish-green leaves. Flower colour was not going to be much use as it noted that colour could be pale pink to white. Then I would confirm ID by looking at the fruit.

Leaf Shape Variation, 26th June 2019 Landguard
On the way I did find an interesting variation in the leaf shape but neither had any glandular hairs so thy must be both be E. cicutarium. Hairs were the normal curved white non-glandular type and the leaflets were cut to about 2/3rds. The version on the right is not typical being more rounded leaflet tips.

Leaf Detail showing dense white hairs

Another variation were some plants having dense wavy white hairs which might make the leaves look grey at a distance. The hairs were mostly non-glandular and the seed showed these plants were E. cicutarium. Note glandular hairs on the leaf stem. These leaves had rounded tips.

Hairy plant with seed in bottom right corner

The leaf shape in this version is more rounded without the more pointed tips. The seed pit shows a distinct rim and the hairs do not overreach the pit making this plant a E. cicutarium.  

Easy Plant.

Once the ID had been established by inspection of the mericarp , I noticed that all the deep pink flowered examples were found to be E. cicutarium. It appears that at Landguard the deeper pink flowered plants are always Common Storksbill. This was backed up by the leaves not being covered in glandular hairs.

E. cicutarium , pink flower with pink anthers and 5 pointed dark pink stigma in the middle.
Note the flower stem and sepals are covered with glandular hair.

Paler flowered plant.

Most plants at Landguard were a very pale pink with shades of blue/lilac. Flowers were small being typically only 8mm in diameter.

Photo of flower
E. cicutarium 
The paler flowers tend to have paler stigma, in this case a pale yellow and the same as the E. lebelii ( see below).  The flowers of both species seemed to be indistinguishable.
E. cicutarium
The colour of these photos is not quite correct missing out a slight lilac blue tinge which was shared with the E.lebelii.


Photo of leaf

E. cicutarium leaf with 99% hairs being glandular
This particular leaf is a typical shape for Common Storksbill with quite pointed tips to the leaflets.
The cuts being 2/3rds deep,  a standard that both Common and Sticky Storksbill conform to. The glandular hairs are erect  and typically 0.2mm long.
Some leaves on this plant had no glandular hairs, possibly older leaves can lose the glandular tips through evaporation, if this were true one would think some trace of the glandular sac would be left. It would appear that some plants have different amounts of glandular hairs on the leaves.
  The main point is that Common Storksbill can have very hairy glandular leaves (which will pick up sand) .  It has also been seen that the leaf shape can be more rounded so it seems likely that leaves may not be a reliable way of separating these two very similar species.

Photo of mericarp (seed case)

Mericarp of E. cicutarium


This photo shows a pit with a definite rim and  beyond the rim there is a clear grove. In practice the groove is a variable feature of E. cicutarium and some literature suggests the groove is not present on the coastal form. I found it was present in most of the coastal E.cicutarium at Landguard.
Hairs over-reaching the pit, a key feature which distinguishes Common from Sticky.
The hairs do not overreach the pit in this photo above .  Unfortunately not all plants show the key feature quite as clearly, with some plants thought to be E.cicutarium based on non-glandular leaf hairs having mericarp hairs that over-reached the pit by up to 25% of the pit diameter.

If Mericarp features are not clearly typical of either species,  it is best to look at another mericarp from a different stalk on that plant.

Another photo of mericarps .
E. cicutarium 
Not quite so easy to see the rim but just possible to make out the groove. More mag needed.


Same picture magnified up to show rim and grove but note that the hairs do over-reach the pit slightly est. 20% of diameter . Problem is that this level of detail is not easy in the field and you really need a X20 lens, more power than most people carry.
E. cicutarium 


3) Sticky Storksbill ( E. lebelii )

Photo of flower showing pale off white (slight yellow tinge) stigma and anthers with pale pink-orange colour. Stigma colour is the same as the coastal E. cicutarium whereas the deeper pink flowers can have a darker pink stigma. The anther here is the anther case which splits off to reveal the yellow pollen on an inner structure. The whole anther structure then falls off and I assume the flower continues on for several days waiting for an insect to bring pollen from another flower.

E lebelii, Landguard




Photo of leaf

E lebelii leaf showing glandular hairs.
The leaves on the E. lebelii tended to be small and rounded however the coastal form of E. cicutarium  can have rounded leaves and also can have glandular hairs so I can't say there is a difference.
E. lebelii
Clapham.Tutin.Warburg mentions the the leaves of E lebelii are almost bipinnate, so I though I would look at leaf shape. Bipinnate implies the leaflets are on a separate stalk to join the leaf. This is case for the lower leaflets but not the ones nearest the tip of the leaf. This arrangement is the same in E. cicutarium.   Vein pattern is limited to a single vein in most leaflets although a vein split can be seen in the top right corner and this is probably a function of leaf size.  See below for a leaflet of 100mm long for Common Storksbill , three times larger than the leaflet for E. Lebelii. shown above.

E.  cicutarium leaflet showing vein split off each lobe.


Photos of Mericarp (seeds)


Small pit, no groove and overreaching hairs 50%, E. lebelii


Hard to make out rim detail, hairs overreaching pit just over 50%. E. lebelii

Hairs overreaching pit by 80%.

E. lebelii  Features like hair overreach visible at green stage.
E.lebelii Mericarp hair over-reach just over 50% across pit.

4) Other features from the literature.
a) Mericarp length 5mm and less for Sticky, 5-6.5mm for Common.  A limited sample measured were

Sticky                 Common (coastal form)
4.5mm                5.1mm
4.8                      5.1
4.9                      4.8 ( with 20mm beak)
4.8                      5
4.0                      5 (with a 32mm beak)
4.5                      5

Almost follows the rules so worth checking this feature.

b) The Wild Flower Key ( Rose) suggest flowers in groups of 3-7 for Common, 2-4 for Sticky but in practice at Landguard the Common had either 2 or 3 flowers coming from a stem ( typically about a 50/50 split ) and Sticky had either 1 or 2. One Sticky plant had only single flowers but typically plants had an even split between 1 and 2.  Whether this pattern is limited to this single site is not known but it dos not follow the literature.

c) Beak length  15-40 mm for Common, beak up to 22mm for Sticky.
 Beak length seems highly variable. The Sticky plants I saw had beaks between 10 and 20mm but overlap with the coastal Common 15-35mm makes this feature of limited use.

Conclusion.

The identification of E. lebelii from the coastal form of E. cicutarium is very difficult. The coastal form is so very different from the normal inland version of the Common Storksbill that you can incorrectly assume it is E. lebelii. My first visit to Landguard resulted in total confusion as I was surprised how similar the Sticky and coastal form of Common were. The confusion was increased by the fact that the hair overreach of the Mericarp pit, as a distinguishing feature, is not as clear cut as you might think.
A second visit was made and  care was taken to really check out the mericarp detail before proceeding to take photos of other features. This was helped by finding an area which only had plants of E. lebelii , before moving onto areas with both types present.

With practice the mericarp detail does provide a good way of separating these very similar species just as the books suggest. The hair over-reach in E. lebelii was always at least half way across the pit whereas E. cicutarium was never more than 20% across and often the hairs did not over-reach at all.
The pit rim can be very hard to see but you just have to look at more mericarps on each plant to make a determination. Many storksbill seeds are not viable having empty mericarps, so you have to find good non-sterile ones to check details like mericarp length.

It is very dangerous to make any generalisations based on a single site, so I would welcome any feedback from experts familiar with other populations which may be different from those at Landguard.

The name of Sticky Storksbill has recently been changed from E. lebelii to E. aethiopicum previously also being know as E. glutinosum in older books.  There are records of hybrids from Wales and South Lancashire but no plants were found at Landguard that fitted the description of the hybrid, which is possibly surprising since both grow together.
The coastal form of E. cicutarium is know as  subs. dunense. but intermediates occur so it not really given any special status.

Basic method for finding a Sticky Storksbill.
1) Find a plant with small leaves that are covered in glandular hairs. Those without glandular hairs on leaf will be E. cicutarium. Note that some stressed plants can lack glandular hairs and this applies to both species. Identification is so difficult I would bypass stressed plants.

2)  Find brown storksbill with good mericarps still attached. Using X15 mag lens examine the pit at the end of the mericarp attached to the beak. It will help to pull off the sepals to get a better view.
Check hair over-reach of the pit. Greater than 50% is good for E.Lebelii.    Some E cicutarium have hairs that over-reach up to 25% of diameter of pit. but many will have no over-reach at all. Check presence of a rim to the pit. this can be very hard to judge. E lebelii should not have any sign of a raised rim. E. cicutarium often has a clear rim and a groove below it.

3) If the mericarp features are not conclusive find another brown mericarp on that plant and check that out, as it may have easier to see features.

Additional note.

The colour of the anthers and stigma are variable but cannot be used to distinguish between the two species as far as I can tell. In general the stigma on E. cicutarium  is normally pink, sometimes quite a dark pink, but white flowered and coastal whitish variants have pale almost white stigma.
The stigma in E. lebelii  are pale white with a hint of green or yellow, the same as in white flowered Common Storksbill.

The anther colour for E. cicutarium is normally a dark purple/blue before it splits to reveal its pollen.
In pale flowered versions it can also be a pale pink and colour it shares with E. lebelii.


White flowered variant of E. cicutarium with pink anthers.




Habitat.


Both species present on sandy shingle areas near Landguard Fort



Landguard Fort,  July 2019



Dry grassland with mostly E. cicutarium

Version 1.2 Updated 19th Aug 2019
Peter Leonard
Rampton
Cambridgeshire
1st August 2019
cambridgewildflowers.blogspot.com

Sunday, 7 April 2019

Viola reichenbachiana and V.riviniana Hybridise?

Common ( V. riviniana) and Early Dog ( V. reichenbachiana) violets have been a much debated subject in regard to intermediate plants being either variation or the result of hybridisation.

The BSBI Viola handbook covers the problems and attempts to provide a practical approach based on morphological features but concludes 'more work needs to be undertaken on the taxonomy of this group'.


I found a paper on the internet (abstract only unfortunately ) that has an interesting claim that in Europe there is no evidence of hybridisation, or that's what I understand it means. Whether this result would apply to plants in the UK is not known.  The paper was written in Eastern Europe and the UK appears not to have been one of the four countries sampled. (I have not been able to review the full paper and would not have the knowledge to understand it anyway. )

It was published in the July 2017 edition of Plant Biology.  The abstract is below the following photos of Viola reichenbachiana variation.  These plants had quite pale spurs and remarkably sharp ends to the purple veins but within the limits of variation. Short sepal appendages well within normal range of V. reichenbachiana. Just an example of variation in Early Dog Violet.


Viola reichenbachiana with quite pale spur , Brinkley, Cambridgeshire, 6th April 2019
Viola reichenbachiana with clear ends to dark veins. Brinkley, Cambridgeshire, 6th April 2019


Plant Biol (Stuttg). 2017 Jul;19(4):542-551. doi: 10.1111/plb.12571. Epub 2017 May 17.No evidence of contemporary interploidy gene flow
between the closely related European woodland violets
Viola reichenbachiana and V. riviniana (sect. Viola,
Violaceae).
Migdałek G1Nowak J2Saługa M2Cieślak E2Szczepaniak M2Ronikier M2Marcussen T3Słomka A4Kuta E4.Author information
Abstract
Viola reichenbachiana (2n = 4x = 20) and V. riviniana (2n = 8x = 40) are closely related species widely distributed in Europe, often sharing the same habitat throughout their overlapping ranges. It has been suggested in numerous studies that their high intraspecific morphological variability and plasticity might have been further increased by interspecific hybridisation in contact zones, given the sympatry of the species and the incomplete sterility of their hybrid. The aims of this study were to: (i) confirm that V. reichenbachiana and V. riviniana have one 4x genome in common, and (ii) determine the impact of hybridisation and introgression on genetic variation of these two species in selected European populations. For our study, we used 31 Viola populations from four European countries, which were analysed using AFLP and sequencing of a variable plastid intergenic spacer, trnH-psbA. Our analysis revealed that V. reichenbachiana exhibited larger haplotype diversity, having three species-specific haplotypes versus one in V. riviniana. The relationships among haplotypes suggest transfer of common haplotypes into V. riviniana from both V. reichenbachiana and hypothetically the other, now extinct, parental species. AFLP analysis showed low overall genetic diversity of both species, with V. riviniana showing higher among-population diversity. None of the morphologically designated hybrid populations had additive AFLP polymorphisms that would have indicated recent hybridisation. Also, kinship coefficients between both species did not indicate gene flow. V. riviniana showed significant population subdivision and significant isolation by distance, in contrast to V. reichenbachiana. The results indicate lack of gene flow between species, high influence of selfing on genetic variability, as well as probably only localised introgression toward V. riviniana.


An interesting abstract for fans of Violets. 
Peter Leonard
Rampton, Cambridgeshire.
7th April 2019 


Wednesday, 3 April 2019

Reichardia ligulata on Tenerife

Reichardia ligulata? on Tenerife.                                                                        11th March 2019

On a short visit to Tenerife we stayed in Santiago Del Teide, in the Teno region, North West Tenerife.
One trip was to drive out to the Punta de Teno, the lighthouse at the very north west tip of the island via the dramatic road that is cut into the northern cliffs.

The area has a short chapter in the 'Natural History of Tenerife by Philip and Myrtle Ashmore' ,  and contains many endemic species with areas of Euphorbia etc.  ( pages 68 - 71).

We drove out to the end of the road and walked out to the lighthouse.

Looking back towards the mainland from the lighthouse at Punta Del Teno.

Far from a green and pleasant land, the area round the lighthouse is almost devoid of plants.


A yellow composite beside the road.
 With only about three plants to look at, I though I better take some photos of a yellow composite growing right beside the road.


First thing to say was I did not recognise it, another strange plant growing in a very strange place.


Crinkled and spiky leaves growing in a clump with flower stems supporting two or three flowers.

Close up of leaf, thick fleshy with spikes.
Thickened stem before the bulb shaped flower head.  Tough looking bracts stick out but no hairs are present, only a few black bumps a bit like the cockscomb on Cat's-ear (but they are hairs whereas these are just bumps).
(There may have been a few hairs on the inside of the bracts at the tip, see open flowers photo below.)


















A more open flower head shows the yellow petals with slight red in the tips.

Open flower

Top view of flower.




Achenes with white simple hairs.

The 'Natural History of Tenerife' does not claim to be a field guide to the plants of Tenerife however it does have many photos of plants to be found in various habitats. One that seemed to fit was found on page 73 with a very short text, 'Another distinctive plant is the composite Reichardia ligulata with crinkled , fleshy, thorny leaves and all-yellow flowers'

This would seem to fit the plant photographed here although the description lacks the detail to be certain.

Google images for Richardia lingulata have several photographs that correspond well to the above plant, however they also have some photos, that despite being labelled as Reichardia ligulata do not resemble the plants photographed here.  

Unlike the the Tree Sonchus, the Reichardia family does not  appear to have multiple species on Tenerife.  Reichardia ligulata is present on all the Canary Island.

Three plants were present at the lighthouse site beside the approach road.


Peter Leonard
Rampton, Cambridgeshire
2nd April 2019




























Saturday, 30 March 2019

Sonchus acculis on Tenerife

Sonchus acculis? , another massive 'dandelion' on Tenerife.


On our walk west of Erjos, the first 'Yellow Composite' seen beside the track was a massive rosette of leaves supporting a single flowering stem that splits to support some large yellow flowers.

 Erjos, Teno Region, Tenerife. 
By British standards this is an extreme plant with its rosette typically a meter across. It is still a 'dandelion' in terms of its flower but still quite a shock to see.

Calling it Sonchus acculis is based on a brief description in the 'Natural History of Tenerife' but without a full description being available there is room for considerable error, especially as Tenerife has apparently 700 endemic plant species.

'Dandelion' type Flower

 Apart from the large size the other strange feature of the flower buds is that they are covered in a thick layer of white hairs. This is especially thick on the un-opened buds where you almost think they are covered in some form of fungal growth.


Some flowers have less of these white fluffy hairs so you can see the bracts, or they may just be wearing off.
Single plant showing leaf rosette.

Leaf with spiky margin.
Large size apparent in this photo.

We continued our walk past the transmission towers and into the laurel forrest where we found more of these plants. Sometime the rosette is not on the ground but supported on a brown stalk which old leaves hanging down.


Rosette supported on woody stalk.
 On the boundary between the laurel forrest and the more open hillside near the transmission towers is a good place to find Bolle's Pigeon.




Detail showing achene.

Peter Leonard, Rampton, 30th March 2019