Is Searsia a nightmare to identify?

Some genera are easy to ID, and others are problematic. How does Searsia fare?

Below are the some of the misidentifications on iNat at present (click the blue to see full details, and select the tab "Similar Species").
The numbers are the number of mis-identifications of the top species.
Clearly, identification of Searsias is not simple, or for the fainthearted.

  • Searsia lucida Glossy Currantrhus 19 species (incl.) 114 S glauca, 96 S laevigata, 93 S pallens, 40 S crenata, 13 S pyroides)
  • Searsia glauca Blue Kunirhus 12 species (114 S lucida, 37 S crenata, 33 S pallens, 28 S undulata, 23 S laevigata)
  • Searsia laevigata Dune Currantrhus 14 species (incl. 96 S lucida, 23 S rehmanniana, 23 S glauca, 22 S tomentosa, 14 S pyroides)
  • Searsia pyroides Common Currantrhus 18 species (incl. 14 S laevigata, 13 S lucida, 9 S tomentosa)
  • Searsia tomentosa Bicolour Currantrhus 13 species (incl. 22 S laevigata, 13 S incisa, 12 S angustifolia, 9 S pyroides, 8 S rehmanniana)
    .

  • Searsia lancea Karee 10 species (incl. 31 S pendulina, 29 S leptodictya, 15 S angustifolia, 5 Olea europaea)
  • Searsia crenata Bluefruit Currantrhus 13 species (incl 40 S lucida, 37 S glauca, 10 S laevigata.)
  • Searsia chirindensis Red Currant-Rhus 6 species(incl. 4 S tomentosa, 3 S pyroides, 3 Vepris lanceolata)
  • Searsia pallens Ribbed Kunirhus 14 species(incl. 93 S lucida, 33 S glauca, 26 S undulata, 15 S longispina)
  • Searsia rosmarinifolia Rosemary Currantrhus 3 species (nothing significant)
    .

  • Searsia angustifolia Willow Karee 7 species (incl. 15 S lancea, 12 S tomentosa)
  • Searsia dentata Nana Currantrhus 4 species (nothing significant)
  • Searsia magalismontana Mountain Currantrhus 2 species (nothing significant)
  • Searsia leptodictya Mountain Karree 6 species (incl. 29 S lancea, 5 S pendulina)
  • Searsia discolor Grassveld Currantrhus 3 species (nothing significant)
    .

  • Searsia pendulina White Karee 4 species (incl. 31 S lancea, 5 S leptodictya, 4 Olea europaea)
  • Searsia rigida Rock Currantrhus 1 species (nothing significant)
  • Searsia undulata Namaqua Kunirhus 9 species(incl. 28 S glauca, 26 S pallens, 12 S longispina, 6 S lucida, 6 S burchellii, 6 S laevigata)
  • Searsia incisa Rubrub Currantrhus 7 species (incl. 16 S refracta, 13 S tomentosa)
  • Searsia pterota Wing Currantrhus 7 species (incl. 41 S longispina, 5 S pallens, 4 S lucida)
    .

  • Searsia scytophylla Redflower Currantrhus 3 species (incl. 10 Searsia lucida)
  • Searsia burchellii Karoo Kunirhus 5 species (incl. 9 S longispina, 6 S undulata)
  • Searsia rehmanniana Bluntleaf Currantrhus 7 species (incl. 23 S laevigata, 8 S lucida, 8 S tomentosa, 5 S incisa)
  • Searsia longispina Thorn Currantrhus 11 species (incl. 41 S pterota, 16 S refracta, 15 S pallens, 12 S undulata, 9 S burchellii)
    &

  • Searsia refracta Roughleaf Currantrhus 7 species (incl. 16 S longispina, 16 S incisa, 5 S pyroides)
Publicado el abril 19, 2024 11:59 MAÑANA por tonyrebelo tonyrebelo

Comentarios

agree, I really struggle with the genus, especially telling pterota and longispina apart

Publicado por andrewgillespie hace 29 días
Publicado por sandraf hace 28 días

R.O. Moffett, 1994, Rhus longispina and Rhus pterota, two hitherto confused South African shrubs,South African Journal of Botany, 60, 43-49, https://doi.org/10.1016/S0254-6299(16)30659-7

Comparison of diagnostic characters of Rhus longispina and R. pterota

Drupe
R.l - Oblate, ellipsoid 3.5 X 2.3 - 6.8 X 4.7 mm, chestnutbrown, drying dark brown; resinous juice and dry drupes, astringent but palatable
R.p - Elliptic, ellipsoid 5.6 X 4.3 - 6.4 X 4.9 mm, slightly asymmetric, dark reddish brown, drying black; resinous juice and dry drupes pungent, distinctly unpalatable leaving a burning sensation in the mouth
Foliage
R.l - New growth glabrous, shiny
R.p - New growth russet, glandular
Leaves
R.l - Petioles semiterete, occasionally margined; leaflets olive-green above, slightly paler below, often laccate; apex often emarginate
R.p - Petiole flattened, distinctly winged; leaflets dull grey-green above, slightly paler below, never laccate; apex never emarginate
Venation
R.l - Secondary veins impressed, not prominent
R.p - Secondary veins prominent above, duJ! yellow, divided towards margin, often somewhat reversed
Habit
R.l - When mature, large rounded shrubs up to 4 m high
R.p - When mature, somewhat untidy squarrose shrubs up to 2 m high
Panicles
R.l - Axillary and terminal, latter prominently exposed
R.p -Fasciculate, not prominently exposed
Bark
R.l - Pale grey-brown to duJ! yeJ!owish on younger branches, granular to slightly striate
R.p - Grey, granular often lichen-covered
Habitat
R.l - Occurs on diverse substrates near the coast and Karoo
R.p - Occurs on calcareous substrates
Distribution
R.l - Widespread near the coast and in the Little and Great Karoo
R.p - along the coast and adjacent interior

Publicado por tonyrebelo hace 28 días

Do we need complexes for some groups??:
.1. Searsia rehmanniana & pyroides
.2. Searsia pallens & glauca

Publicado por tonyrebelo hace 28 días

Great comparative summary Tony. Thanks. Still haven't a handle on longi. Pterota is common in thicket close to the coast, western section of Garden Route.

Complexes? Probably for me no.
As a veldmuis, exposure to the species in the field works best for me.

What do the others say?
@galpinmd @jeremygilmore @steven_molteno @annsymons

Publicado por sandraf hace 28 días

My opinion re complexes is to hold off for the time being, but my hesitation is largely based on not being aware of what the benefits are. @tonyrebelo What would the benefits be in lumping some of the observations into a complex?
I agree with @sandraf in that field experience is the best option in being able to separate some of these species with overlapping features. The issue of course with field work is that I am restricted to the small area in which I live and the species that grow here. I was thinking of putting together a post with some details of what to look for, and hence photograph, when it comes to the Searsias (the species I'm familiar with that is) as I have found that in many cases some additional pics would have helped in being able to ID a specimen.

Publicado por galpinmd hace 28 días

Agreed that the genus is not easy to get a handle on but the past 6 - 8 months there has been considerable improvement and the CV is becoming effective, one step at a time.
Complexes - a strong no vote from me. That would negate the learning that the identifiers have acquired through dint of hard work! (fun too - otherwise we wouldn't volutarily be doing it - the human ones).
However, the need for subspecies, variants and that ilk really does need refinement on iNat's side - to make better provision for doing comparisons at the deeper levels.

So we really need those votes - please tell the participants in this thread how to go and vote, asseblief. Tony.

Publicado por annsymons hace 28 días

OK - you guys obviously do not understand complexes. Say we have 100 observations. 30 are rehmanniana, 40 are pyroides, and 2 are clearly hybrids. However, 20 of the other 25 could be either of the two species, but we cannot tell, and 5 are some other species not yet identified to species (pending).

So at present we have:
Genus:
3,025 Searsia (25+ all the others waiting for ID)
Species:
30 S rehmanniana,
40 S pyroides
2 S rehmanniana x pyroides (do we add it or ignore them?)

But if we add the complex then we have:
Genus:
3,005 Searsia
Complex (contained in the genus)
20 S rehmanniana-pyroides,
Species (contained in the complex):
30 S rehmanniana,
40 S pyroides
2 S rehmanniana x pyroides (do we add it or ignore them?)

So: complexes are really useful. But it all depends if the complex will contain only a few observations, then it might as well just be identified to genus. But if there are dozens of observations, then it is better to take them out of the genus bin, and group them in the complex bin.
So the question is not if Complexes are useful. They are indispensable. The question is whether there are enough unidentifiable species pairs and triplets to justify having them in the genus Searsia.
Here are the complexes currently for southern Africa (in descending order). Click on the genus-species to see the Complex (the taxonomy tab will tell you the children in the complex and how many observations. (e.g. Seriphium plumosum complex has 557 observations at complex level, and -inter alia- 2,495 Seriphium plumosum and 863 Seriphium cinereum observations, totalling 4,126 observations):
https://www.inaturalist.org/observations?place_id=113055&rank=complex&verifiable=any&view=species
(click on the ### observations to see the observations identified to complex rank).

Publicado por tonyrebelo hace 28 días

@annsymons - do you want to vote on nightmares, or complexes, or specific complexes?

Publicado por tonyrebelo hace 28 días

Oh: I should mention Complexes are named after the dominant species. Which does lead to confusion: people muddle up Searsia rehmanniana Complex with Searsia rehmanniana species. I continually ID the Oak, as Quercus robur Complex while meaning to do species. It is quite confusing, and slips in very easily.
This is a downside that we need to consider. But most identifiers in Searsia will be aware of these difficult "complexes".

Publicado por tonyrebelo hace 28 días

@galpinmd
Compact guidelines of what to photograph sounds good! Can be added as a Journal post.

(And local area knowledge is invaluable. It's the diving board for ripples. Without iNat all pterotas would still be longispinas! ;-))

An easy species guide - traits to look for and how to identify can be added to Tony's amazing Searsia guide:
https://www.inaturalist.org/guides/18203?view=card
Preferably keep it accessible to the largest audience by sticking to KISS - Keep it Short and Simple. Limit confusing botanical terms.

Complexes: ..... digesting. Appears to be handy to pigeonhole the observations into more manageable units. I did need that explanation too Tony!

Publicado por sandraf hace 28 días

I'm with Tony on the complexes. I've found them very useful in other genera, and I think they'll probably be useful for Searsia, particularly because Searsia doesn't seem to have recognised infrageneric ranks (subgenera, sections, series). At least none that I'm aware of.

Imo anything that helps us get to more precise IDs is good.
It is often the case that you know for certain that an observation is a part of a particular group of species (eg. the Searsia undulata-pallens-lucida grouping). But it's not clear which of those species it is. Maybe because it's an intermediate (or perhaps even a simple hybrid).

Being able to ID it at least to the complex, is much better than leaving it as just "Searsia" (which doesn't tell us much).
It's also much better than giving a falsely certain species-level ID to something that's really an intermediate (which is misleading).

Publicado por steven_molteno hace 28 días

I am not discussing complexes at all - am likely to bail out of idetifying Searsia's if it goes that way.
I was referring to voting for the request that iNat provide more levels below species - ie
a need for subspecies, variants and forma really does need refinement on iNat's side - to make better provision for doing comparisons at the deeper levels. I want to be able to open the 'compare this obs with (only) other obs of eg: Searsia lucida elliptica or Searsia laevigata villosa when I enter that as my identification in the ID box - not have to go to a separate (sub-taxon) page to see the features of RG obs of that level.

Publicado por annsymons hace 27 días

Thanks @tonyrebelo and @steven_molteno for providing more clarity regarding the use and usefulness of complexes. I agree that they can be beneficial in moving an observation towards a more precise ID (as opposed to just staying at genus level). I do believe many of these currently confused pairs (e.g. rehmanniana var glabrata and pyroides var pyroides) can be identified to species level (Well, at least I hope so!)
If I may suggest we hold off creating complexes for the time being as we digest the concept and familiarize ourselves with navigating complexes on iNat

Publicado por galpinmd hace 27 días

Re: Do we need complexes for some groups??:
.1. Searsia rehmanniana & pyroides
.2. Searsia pallens & glauca

No, not for these four species. They are well defined. Often the observations just lack sufficient visuals to go on.
[Though a system to herd together the uncertain ones sensibly might be useful? I'm not far enough into Searsia-ing to suggest constructive suggestions.]

And yes, thank you for the Complexes tut and input, Tony and Steven!

Publicado por sandraf hace 26 días

Complexes ARE for well defined species. The are specifically for species were visuals dont help with identification, either because they are hidden, on a side difficult to photograph or internal.
But they are only useful where there is a genuine problem. Reviewing the IDs, I noticed over 10 IDs to genus with notes "either Searsia rehmanniana or pyroides" and more than five "either Searsia pallens or glauca" - which is why I asked.
Unfortunately I cannot direct you to them (if they were in a Complex I could) because there are still over 2,600 observations to genus waiting to be identified.
(although this will narrow it down a bit: https://www.inaturalist.org/observations/identify?reviewed=any&quality_grade=any&verifiable=any&project_id=searsia-in-southern-africa&lrank=genus&place_id=any&ident_user_id=galpinmd )
here is an example: https://www.inaturalist.org/observations/202078231

Publicado por tonyrebelo hace 26 días

Thanks Tony. Got it

Publicado por sandraf hace 26 días

The longispina vs. pterota issue tends to surface from time to time.
Comments on Journal posts do not reflect on the App's activity feed (not on my Android at least), but Journal items do.
@tonyrebelo could we copy/paste it as a new Journal item, please?
That way it is easier to reference to a Jounrnal link in observations as well.

Publicado por sandraf hace 24 días

I will do if-when we decide to go the Complex route.
I dont think a journal item is warranted if we are just going to pass on it.

Publicado por tonyrebelo hace 24 días

Are you suggesting a pterota-longispina complex too?

Publicado por sandraf hace 24 días

As we 've been working through the various species we go through points of "WIP" so if I look at the obs of Mark Galpin's that you refer to above (202078231), Tony then it is a place-marker for him. When he works through again refining those obs, that comment would be a pointer if it were mine. If that is the function of a 'complex' bucket - maybe; but to my mind it muddies water that is deeply tannined to begin with!
I do not see how introducing complexes can simplify the process of getting to solid Research Grade obs that are actually worthwhile for research purposes.

Publicado por annsymons hace 24 días

I am aware that the above thread is more about 'complexes' but I've been doing a little more digging re the differences between rehmanniana (RH) and pyroides (PY) and have had the good fortune of getting into contact with Prof Rodney Moffett. He is an elderly gentleman now but is quite sharp and is willing to help with Searsia ID. I sent him some pics of observations of RH/PY(links below) from my general area.
https://www.inaturalist.org/observations/206073025
https://www.inaturalist.org/observations/184985140
https://www.inaturalist.org/observations/196752606

His comments on the above three observations follow:

"I would place all three in iNaturalist as Rhus macowanii, now S. rehmanniana var. glabrata.. From Schonland's comments in my Flora treatment you will see that it is a variable species. Looking at all the specimens in my Ph.D. thesis I don't have S. pyroides from your area. It occurs further inland in drier country"

"S. rehmanniana var glabrata and S. pyroides var pyroides are not easy to tell apart. Habit is often a key factor with the former more sprawling and the latter more compact. The latter's leaflets are also not as rough and I would place your images under Searsia rehmanniana var glabrata, the old Rhus macowanii from your area"

From his comments it appears that PY occurs mainly in the drier areas in the rain shadow of the fold mountains and further north. The specimens to the south appear to be mostly RH. It was something I missed in the comments on PY var pyroides in the Flora treatment. It states that this species occurs in the 'southern Cape interior' - I just saw southern Cape and missed the 'interior' part.
Anyway, it's a start - still got a ways to go though.
Please feel free to disagree with my ID's if you feel I've missed something - I do actually find it helpful.

Publicado por galpinmd hace 23 días

Thank you Mark.
Not any easier to ID them I suspect, but guidelines at least!

Publicado por sandraf hace 23 días

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