Tillandsia rothii
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Tillandsia rothii

Bruce Dunstan 04/13. rothii ?
Peter Tristram 04/13. jalisco-montecola -AS380.
Peter Tristram 04/13. rothii -VBG_0752.
Peter Tristram 04/13. rothii & ionantha -VBG_0751.

Bruce Dunstan 19/4/13 - I got this plant labelled as T. roland-gosselini. Do you think it may be closer to T. rothii ? Any illuminating thoughts would be much appreciated.

Derek Butcher 19/04/13 - It is that old chestnut again. Sue Gardner in the 1980s reported that in the vicinity of T. rothii you do find plants with T. roland-gosselini looks which made her think that T. rothii could well be a hybrid. My view is that in the core habitat you find true T. rothii but the further you get from this core anything goes. So they may look like T. rothii vegetatively but when they flower!?

Bruce Dunstan 19/4/13 - The inflated bracts suggested some jalisco-montecola influence in it compared to other roland-gosselini images I have seen. I remember when we discussed 'Amigo' and 'Bob's Amigo' that rothii was thought to be a hybrid. Still very attractive plants when they spike.

Peter Tristram 22/4/13 - Andy. As you have visited the area where T. rothii, jalisco-montecola and I>roland-gosselini grow are you willing to add to this discussion ? I was in away at the moment but I have a thought that it is more rothii with those inflated bracts and relatively short flower stem, though that could be pretty arbitrary. Do you think jalisco-montecola is involved in rothii or are they a separate pulation? (Ed.- Andy Siekkinen will be a speaker at Bromsmatta'15 conference, and travels to Mexico frequently.)
Peter Tristram 23/4/13 - Pictures T. jalisco-monticola-AS380-DSCF5190, VBG-T-rothii-IMG_0752, VBG-T-rothii-IMG_0751, Vallarta-vBG-T-rothii-IMG_0758, Andy-T-rothii-s-AS377-DCSF5165, Tillandsia-roland-gosselini-s-IMG_4392.

Peter Tristram 04/13. Vallarta-rothii-vBG 0758.
Andy Siekkinen 04/13. Andy-rothii-AS377-DCSF5165
Andy Siekkinen 04/13. Andy-roland-gosselinii-IMG_4392

Andy Siekkinen 23/4/13 - Looks like T. rothii to me. Like any Tillandsia they are quite variable. Color, size, scape length and shape of the paddles are all variables. T. rothii actually has quite a wide range. Definitely gradations as you go from spot to spot, but gradation is probably an imprecise word choice. The easiest thing to see is that the size varies from spot to spot, not necessarily as gradations.
"Usually" roland-gosselinii has the smaller 'body' with a taller scape relative to the leaves, but some are tiny. I'm sure you remember the really big population I saw (photo attached). This plant and the ones in the spot were easily 3-4x larger than the majority of the roland-gosselinii range (which is quite a big area). There are some spots that T. rothii gets as big as well. But even so the paddles are usually quite different. Even when T. rothii paddles aren't super inflated, they still seem to always have a 'more beefy' appearance. Here are some other more typical sized T. rothii at the local botanical gardens.
I'll try to make a post summarizing some more photos soon.
And to add to it, in the heart of T. rothii habitat I found what look to be very similar plants to T. jalisco-monticola. The habit of the plant looks a slight bit different--pups a bit more frequently, the plant seems a little bit smaller and just looks a bit different. But the interesting thing was that they were only at 150' elevation. Much different than up in the mountains where they seem to appear around 1300-1400' elevation.
Okay, more later...

Peter Tristram 24/4/13 - As promised, Andy has added to his observations and thoughts. Attached are pics of a rothii from Tropiflora in 2010 that I currently have in bloom that didnít flush in the leaves and one that I bloomed in 2011, bought off Maurice in Albury a few yrs ago. I assume it was seed raised and from what I have seen, rothii from seed is the spitting image of mum and dad. If the hybrid origin premise is true I would think there would be a range of plants from roland-gosselinii to jalisco-montecola looking. Iím inclined to agree with Andy that any hybridisation was fairly distant, but then, probably the case with most Ďspeciesí. It is always interesting to get opinions on topics like this from an observant person who has seen the plants in the wild. See photos T-rothiiTropiflora-PT, T-rothii-inf-Tropiflora-PT, T-rothii-MK-PT, T-rothii-inf-MK-PT.

Peter Tristram 04/13. rothii-Tropiflora.
Peter Tristram 04/13. rothii-inf-Tropiflora
Peter Tristram 04/13. rothii-MK
Peter Tristram 04/13. rothii-inf-MK

Andy Siekkinen 23/4/13 - (relating to whether rothii could be a hybrid:)
I certainly wouldn't shun the idea completely, but it would have had to have started a long time ago. When we are so close, it is too easy now to just say, "wait until someone does the genetic study". The biggest problem that would prevent me from being so excited about the hybrid origin is that the leaves and habit are so close between T. rothii and roland-gosselinii but so different from T. jalisco-monticola. Of course given the proximity of T. jalisco-monticola and T. rothii, I certainly wouldn't argue that there may simply be some long term gene-flow...which I guess would be a 'hybrid origin'. But I have yet to see anything that resembles a clear halfway intergrade between T. jalisco-monticola and T. rothii. Of course, it could also be argued that the difference in leaf morphology could be limited by the substrate that they are on...assuming that T. rothii is more like T. roland-gosselinii and prefers smaller branches. But I would definitely stop short of saying that as that is only relying on memory without actively looking at the branch size. I have seen T. roland-gosselinii type plants all the way north into southern Colima (and it is supposed to be documented into Jalisco), so not all that far away from where I have seen T. rothii in Jalisco. You can tell I am waffling and hesitant to make any hard claims. It will take a lot more field work before I would argue strongly either way.
Gardner's claim about there apparently being specimens that show to be hybrids but strongly favoring one parent or the other feels a bit 'soft' to me, but again, without spending more time there and looking at a lot more plants I certainly couldn't argue with her conclusion. It just feels odd to me that the leaves would favor one parent or the other so strongly. All of the natural hybrids that I have seen sure seem to show intermediary features that you can easily pick out as being different and usually right in between the two parents. So my gut is suspicious. But (again hedging my bets), if the local niche or branch size provides a strong selecting function that weeds out anything right in the middle it could make a lot of sense. That way you can get some gene flow between the species while not allowing it to become a full and messy hybrid swarm. I hope what I am saying is clear. I feel like I'm not quite explaining it very clearly.
It will take a lot more time in that area to get a better feel of where they either stop or meet. There are still lots of interesting things in that region. There is a form of T. marabascoensis that has a branched inflo. I think I have seen up to 5 or so branches. So a bit different than the description that made a point of specifying a simple inflorescence. So lots of fun field work required. I guess I can force myself to keep going back! Ha ha!
Not sure if I helped at all with the discussion that you guys are having, but the plant that you attached the picture of is definitely T. rothii.

Bob Hudson 25/4/13 - I was not going to enter this discussion but here are a couple of pics. T. rolland- gosselinii George Stamatis and T. rothii from Birdrock.

Bob Hudson/George Stamatis 12/12. roland-gosselinii.
Bob Hudson 04/13. rothii from Birdrock
Chris Larson 03/19
Peter Tristram 25/4/13 - Hi Bob, my 2 BOBís worth is they all look like T. rothii. I wonder where George got his "T. rolland- gosselinii" from ? Iíll be interested to see what my rolland- gosselinii plants bloom like too! Have you bloomed the seedlings you had? Bloody nice plants!
Bob Hudson 26/4/13 - I bought these from George in Sth Africa so my guess they were from Dennis Cathcart.
Chris Larson 02/21
Chris Larson ... "Every second flowering it looks good for me."
Ray Clark ... "What you are using for a potting medium please?"
Chris Larson ... "None."
Adam Bodzioch ... "Well done Chris. IMO rothii is hard to colour up properly out of the tropics."

Updated 08/02/21