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Drosera graminifolia and D. spiralis, re described..

I remember this talk. What would you do if I said they all look the same?
 
I'd say you didn't read the article! ;)

I can send you a pdf copy of the article if you wish to read it, just shoot me your email address. But here's a nice little summary: http://carnivorousockhom.blogspot.com/2012/12/re-establishment-of-drosera-spiralis.html

And be on the lookout in 2014 for the publication of a 3rd species from this group, discovered only a month ago. It actually looks somewhat like D.regia and competes with it for the title of the largest sundew in the world. Here's a pic of me holding one:



Happy 2014 to all!
Fernando Rivadavia
 
So all we need to add to the fun is to find that genetically this new plant is closely related to D. regia. Much like D. meristocaulis is related to Pygmy Drosera.
 
I wish... I can tell you it is not. Sorry to spoil the fun. :) It's got characters of both graminifolia and spiralis, but seems to be closer to the former (including habitat), although still very different from both.
 
This is the most exciting carnivorous plant discovery in a long time. Do we have a potential name picked out yet ? Can't wait to see it introduced into cultivation ! Good work Fernando !

On a side note......I supposedly have both D.spiralis and D.graminifolia. The D.spiralis is indeed D.spiralis, the D.graminifolia is in question however. Are intergrades between the 2 species possible ?

Here is my D.spiralis.




And here is the plant I got as D.graminifolia.

 
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I don't know if it is a case of D. graminifolia being rare or just that D. spiralis is more common having been in mass tissue culture for a time. I read the article several months ago and going through my mind is if the differences are enough for species elevation or at most a var. But not having the advantage of studying the plants in-situ or even have examples of both in cultivation my opinions mean nothing.

I do have the plant that was sold by AG3 as D. graminifolia. There was a brief time when there were enough of these on the market that a few nurseries were giving them away as a bonus with orders. From the descriptions, diagrams and photographs from the article mentioned above this plant would appear to qualify as D. spiralis. However I'm not so sure about the characteristic of regiular circinate vernation vs eccentrically circinate leaf growth pattern. In my observations of the plant(s) that I have cultivation is that when the plant is younger (from cuttings or offshoots) the leaves grow "regular" circinate vernation. And another obervation in more mature plants one day the leaves may be "perfectly" circinate and a few days later they will be eccentric and "knotted" and a few days later be back to "perfect". I've not made any observations as to any cause for this - is it wind (I grow these outdoors all year round), ambient humidity or because I got lazy and skipped watering them? Maybe a combination of the factors? But then again observing plants in cultivation is not a good way to judge on how they grow in-situ.

I was fortunate enough to get it to flower a couple years ago. It may be a couple years before it flowers again as for one reason or another the plant died down to the root but has grown back.
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Here is the plant from late summer of 2012. It died back to the roots a few months later.
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Hey guys,

Thanks for the great pics and congrats on your plants!!

Let me start with a little bit of history. D.graminifolia was one of the 1st CPs I ever saw in the wild, during a high school senior trip to the Serra do Caraça in May 1990. In the 90's I revisited these mountains multiple times and climbed the 4 highest peaks, all of which proved to have this species. Caraça is the type location for D.graminifolia and it is know from nowhere else (if you accept D.spiralis as a separate taxon).

During those early years of my CP explorations, I was able to spread seeds of D.graminifolia far and wide, many people began growing this species, which was previously unknown to cultivation -- AFAIK. Between 1992 and 1994 I also explored for the first time areas further north along the Cadeia do Espinhaço highlands, surrounding the town of Diamantina and also on the Serra de Grão Mogol, where I found numerous populations of what I now refer to as D.spiralis. Seeds of these plants were also spread around the world and plants from Diamantina, Grão Mogol, Itacambira and other sites are still found in cultivation today - while plants from Caraça are not, proving (to me) that spiralis is easier to grow even though they were introduced to cultivation after graminifolia.

Now regarding their taxonomy, it was immediately obvious to me that the northern plants (spiralis) were different from type D.graminifolia, but it took me 20 years of field and lab work to finally acquire a better understanding of just how different they truly were, together with the help of many friends and botanists along the way, including in the latter years my co-author Paulo Gonella. And the main question discussed always seemed to be the taxonomic rank: species, subspecies, or variety?

According to botanical rules, the geographic separation alone is sufficient to classify graminifolia and spiralis at subspecific level, and not varieties. But we could go on for another 20 years or more discussing here whether all the morphological/ecological differences listed in our article justify a separation at species level, since everyone has slightly different species concepts and there is no quantitative line that you can draw in the sand that would convince everyone one way or another.

However in my mind, the choice for species (versus subspecies) boils down to two main arguments:

1.) "Forget the long thread leaves" argument: Thread-leaved sundews are rare. The long narrow leaves are an unusual character that stand out and draw all our attention away from the rest of the plants, something that is hard to ignore and that we repeatedly keep going back to whenever discussing the taxa involved. It's a taxonomic distraction. So much so that some people have even suggested in the past a close relationship between graminifolia/spiralis and filiformis/tracyi - although we now know for sure that this is merely a good example of convergent evolution for leaf shape. And it was thanks to discussions with Barry Rice about the separation of D.filiformis and D.tracyi that I was finally convinced that D.graminifolia and D.spiralis are also good species. Barry had a very simple argument: forget for a minute that filiformis and tracyi have long thread leaves, pretend they have a more typical spatulate-leaved flat rosette, and now apply all the other characters that distinguish the two taxa. It took me a few seconds to work out this mental exercise, imagining something like a D.spatulata as a starting point (representing D.filiformis), and then applying one by one the characters that distinguish D.tracyi. The resulting imaginary plant was not only very different from the original D.spatulata model I'd started with, but it was something that I would most likely consider a good species -- if I ever came across it in Australia. Surprised at my own conclusion (until then I was not convinced filiformis and tracyi should be different species), I immediately performed the same mental exercise with graminifolia and spiralis (which are far more different from each other than filiformis/tracyi), starting with a D.spatulata-like model representing graminifolia, and then adding one-by-one the main characters that distinguish spiralis:

- much shorter petioles
- much larger stipules
- less hairy backside of the leaves
- totally different glandular trichome type on leaves and scapes
- glandular tentacles present on sepals
- irregular circinate leaf vernation
- thicker leaves with semi-circular petiole cross-section
- leaf apex narrower
- smaller, rounder seed
- separate geographic distribution
- different kind of habitat
- different flowering periods

And I was immediately convinced: morphologically and ecologically these characters would be more than sufficient to separate at specific level any two closely related rosetted taxa with spatulate leaves. D.graminifolia and D.spiralis were finally good species in my head.


2.) The argument for conservation: D.graminifolia is a narrow endemic (whereas D.spiralis is widespread) only know from small populations on 4 peaks. Although inside a park, they sit right next to huge mining areas (see Google Earth), which in the late 90's nearly caused their extinction due to some kind of pollution/acid rain effect that annihilated nearly all the vegetation on those mountain tops (and certainly resulting in the extinction of other endemic species that I have no knowledge of, as well as possibly locally eradicating G.violacea and U.reniformis - BTW, Caraça is the type location for the latter). At the type site of D.graminifolia on the Pico da Carapuça, the population was reduced to a single healthy adult plant in the early 2000's and the beautiful orange Sphagnum carpets I'd first seen in 1992 were gone. Fortunately, they have recovered quite well over the past 10 years, I am not sure why. Whatever pollutant was being spilled must've stopped. I'm sure it was pure luck though, and not a conscious decision from the mining companies, assuming they even knew what they were causing. Therefore, moving forward (and ignoring the possible dooming effects of the genetic bottle neck caused by the population crash), the best chance for future conservation of this taxon (in case it ever runs into trouble again) is to classify it at species level. Saving a mere subspecies simply doesn't attract as much conservation attention.


Johnny:
>This is the most exciting carnivorous plant discovery in a long time. Do we have a potential name picked out yet ? Can't wait to see it introduced into cultivation ! Good work Fernando !

Thanks!! The new species does have a name already in our heads, but you will have to wait for publication before it is official. ;) That shouldn't take too long though because the plant is so unique in its characters and it has never been seen before. That is, we will not have to go into lengthy discussions (such as the one above) because it is so morphologically distinct, and most importantly, because there are no previous collections known for this plant, we will not need to revisit herbaria to study material better, and we will not need to do lengthy literature research on what previous authors wrote about this taxon, so that we can discuss in the article why we agree or not with what they wrote.

>On a side note......I supposedly have both D.spiralis and D.graminifolia. The D.spiralis is indeed D.spiralis, the D.graminifolia is in question however. Are intergrades between the 2 species possible ?

From what I can tell from your pics, both your plants are D.spiralis, but we'd need to look a little closer at your "graminifolia" for the characters mentioned above (which are not so clear in your pics). AFAIK, nobody has made hybrids between spiralis and graminifolia yet, but I do not doubt they are interfertile, considering that Dani O. on CPUK has successfully crossed numerous tetraploid Brazilian sundews, even making odd hybrids like D.spiralis X D.camporupestris!


"Not a Number":
> I don't know if it is a case of D. graminifolia being rare or just that D. spiralis is more common having been in mass tissue culture for a time.

Maybe we do need to try to get graminifolia into TC, it might've only been done with spiralis.

>I read the article several months ago and going through my mind is if the differences are enough for species elevation or at most a var. But not having the advantage of studying the plants in-situ or even have examples of both in cultivation my opinions mean nothing.

Well, as mentioned above, at least subspecific rank is justified by botanical rules (geographic isolation). But I hope that you too will come to the separate species conclusion after performing the "forget the thread leaf" mental exercise mentioned above. BTW, your plants shown above are definitely spiralis and not graminifolia.


> I do have the plant that was sold by AG3 as D. graminifolia. There was a brief time when there were enough of these on the market that a few nurseries were giving them away as a bonus with orders. From the descriptions, diagrams and photographs from the article mentioned above this plant would appear to qualify as D. spiralis. However I'm not so sure about the characteristic of regiular circinate vernation vs eccentrically circinate leaf growth pattern. In my observations of the plant(s) that I have cultivation is that when the plant is younger (from cuttings or offshoots) the leaves grow "regular" circinate vernation. And another obervation in more mature plants one day the leaves may be "perfectly" circinate and a few days later they will be eccentric and "knotted" and a few days later be back to "perfect". I've not made any observations as to any cause for this - is it wind (I grow these outdoors all year round), ambient humidity or because I got lazy and skipped watering them? Maybe a combination of the factors? But then again observing plants in cultivation is not a good way to judge on how they grow in-situ.

You bring up a very important point (and observations) regarding the differences in leaf vernation!! So the reason why young leaves are regularly circinate in D.graminifolia and (usually) irregular circinate in spiralis all boils down to the thickness of the leaves! The leaves of graminifolia are flatter (transversely elliptic in cross section near the base), which allows them to be curled up very neatly in developing leaves. On the other hand, the thicker leaves of *MATURE* D.spiralis (semicircular in cross section near the base) *usually* result in the irregularly curled young leaves. There are exceptions of course, especially with plants whose leaves may not be as thick because they are younger or because they grow in less than ideal habitats, maybe somewhat shaded. But even in the most robust specimens, as each young leaf unfurls it will change from an initially very irregular circinate vernation to a regular circinate vernation once about half the leaf is already exposed.

Therefore, age or ecological factors may play a small part (by determining the thickness of the leaf, which in turn determines the regularity of the leaf vernation), but mostly you need to pay attention to the vernation when young leaves are still at the initial stages of unfurling from the center of the rosette - and not when the leaf is already more than half uncurled (as in Johnny's "graminifolia" pics above).

I'm sorry this whole message turned out to be so lengthy, but I hope you have the patience to read though it all and that it helps you guys to ID your plants! :)


Best wishes,
Fernando Rivadavia
 
  • #10
I appreciate the detailed description of the differences between D. spiralis and D. graminifolia, Fernando. The 'forget the thread leaves' idea certainly does make it all more clear. 'Sounds like D. graminifolia is on the rare side in cultivation.

The new species is certainly one of the most exciting new things I've seen in the genus. Congratulations! 'Can't wait to hear about it in cultivation.
 
  • #11
Hello Mark,

I'm glad my long explanation made sense, thanks for the patience to read it all. ;)

Yes, D.graminifolia is exceptionally rare both in the wild and in cultivation, unfortunately.

As for the new species, it is even rarer in the wild (only known from on site), but will hopefully be easier in cultivation than D.graminifolia. However the habitats of the two are very similar, so don't keep your hopes up... :/


Best wishes,
Fernando Rivadavia
 
  • #12
Thank you Fernando for further clarifying the thought processes. I had read the paper several months ago and remember the "forget the threadleaved" paradigm. Mindset can certainly affect perception. A lot of the devil is in the details but you also have to compare populations as well as individual plants. People get the "it's just D. capensis" when they see D. villosa (even Saint Hilaire noted the similarity in his diagnosis). The devil between the two species is in things like the stipules, hairs/glands on the petioles/lamina/flower stalk/sepals etc.

When examining the AgriStarts 3 plant since I had questions about the circinate leaf vernation I compared what details I could - shape of leaf tips and cross-section, shape of stipules, presence/absence of trichomes and sessile glands on the leaves, anthers and stigma. I couldn't compare flower stalks or sepals or seeds. On the basis of these I had determined it was most likely D. spiralis. Your explanation on variable leaf growth makes sense. It would seem that while the cricinate leaf vernation is and obvious and important species identifier it really isn't the most significant one. An example of an obvious, important and very/most significant identifier would be the flower stalk on the re-discovered D. ascendens.

I try to impress upon people not to rely on one characteristic to identify an unfamiliar species and that details such as stipules, flower stalk growth, hairs, glands on the leaves, flower stalk, sepals, flower structures and seed all play significant roles in species identification. Merely browsing through the CP Photo Finder isn't good enough as often times plants are mis-identified/labeled or don't show enough detail of the finer structures. Use the finder to narrow down likely suspects and then track down the published descriptions of the plants. If you can find a recent taxonomic key so much the better. You can find Saint Hilaire's book online - even though the diagnoses are in Latin (note Google translate chokes on many botanical Latin terms - those of you who are "fluent" in botanical Latin help us out by training Google translate with better translations). You can find many herbarium specimens online too.

Speaking of flowers and seeds do is it known which of the species are self-incompatible? It would seem that almost all of the Villosa Complex that are already in cultivation are self-incompatible.
 
  • #13
Hey sorry for the late reply!

AFAIK no Brazilian sundews are self-incompatible, although I have heard many complain over the years that they do not get seed. Maybe it's a humidity thing? Try the Andreas Fleischmann strategy: cut the styles short and add pollen to the stumps. This way, the pollen grains need only grow short tubes to reach the ovules.

Good luck!
Fernando Rivadavia
 
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