Tillandsia atroviridipetala
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Tillandsia atroviridipetala
Species, Mexico.
Ken Woods 12/06.
Peter Tristram 12/13. Large form from Quiroga. (Lydia)

Rob Bower 06/17
Peter Tristram 06/17

Rob Bower ... "Not rare but what a little gem."
Chris Larson ... "Not rare, but slow. (Though not easy to replace when one dies.) Always a joy to see them flower."
Peter Tristram ... "What a thrill! Mexican tectorums are gems! Good to see one alive and well in the north. The last few hot summers have decimated my atros and plumosas though many of the other atro group species are doing fine. You must have a nice breezy spot. Look after it as it's unlikely replacements will be able to be imported for some time."
Rob Bower ... "Are these related to tectorums or is Mex tectorum just a term. My plumosa overnighted in the pool after a storm but survived. My plagiotropica and erubescens died in the heat last summer."
Peter Tristram ... "Sorry, but there are many green/yellow flowering Tills in Mexico and I only meant the atro group. Derek Calls them 'the Little Green Mexicans'.
I took a couple of screenshots of charts I got from Barfuss and Till. The two groups, tectorum and atroviridipetala, are now in the subgenus Viridantha of Tillandsia. It was considered as a genus name for the Mexican species with green/yellow flowers for a while but the dna put paid to that. Take a look at the phylogenetic (dna) chart Viridantha1 from the first paper which Jose introduced in a talk in NZ in 2013. The atro and tect groups are evolutionarily very closely related, so share a pretty recent common ancestor but evolved separately in Nth and Sth America into the current lot of species and intergrades. The latest chart, from the massive Barfuss et al study last year, only sequenced a few from the group - heteromorpha and rupicola from tectorum country (Peru, Ecuador) and lepidisepala, plumosa and tortilis from atroviridipetala country (Mexico). Still a lot of species to be sequenced and a lot of publications to come, some already underway."
Eric Gouda 12/18
Dale Dixon 04/19
Eric Gouda ... "This one is from Renate Ehlers and she named it as a 'pendunculous' Tillandsia atroviridipetala Mexico, Mazamitea - Zamora.
Judging the plant, it seems to intermediar to T. plumosa and T. ignesiae. More images can be found on my own Tillandsia site: http://tillandsia.nl/site/collectie.php?id=700"
Dale Dixon ... "Full sun from 11:30am onwards. Good air movement and good humidity."

Tillandsia atroviridipetala var. yagulensis

Note: These so-called "Little Green Mexicans" (atroviridipetala) belong to a sub-genus of Tillandsia.
A recent paper from Mexico has raised this sub-genus to genus level, Viridantha.
Note in the Key shown below, that atroviridipetala var. yagulensis has been moved to species level, Viridantha yagulensis
Peter Tristram 04/12. var. yagulensis
Stephen Haines 05/16
Peter Tristram 04/12 ... "Holm has grown T. atroviridipetala var. yagulensis from seed and his plants are most distictive in that they are slightly caulescent as they mature. Some of you would have these from me. Evidently it selfs like many of the ‘little green Mexicans’. This one is a pup from Lotte, from Yagul, Mexico."
Peter Tristram 05/17
Peter Tristram 05/17 ... "Every now and then something in the Mexican atroviridipetala group is displayed. Generally speaking the plants are quite rare in collections and are certainly not as easy to multiply as their fuzzy Andean close relatives. I got this baby as atroviridipetala var. yagulensis on a trip to Germany, from Holm in 2006 I think. It’s a big (for this group), semi-caulescent plant, so is likely correctly labelled. Identifying what’s what isn’t all that easy and Renate’s book is invaluable to have any hope.
I was pleased that most of my species in this group made it through the heat, though not all. Unfortunately deaths cannot be replaced anymore. I do hope it pups!"

Key to identify species in sub-genus Viridantha 2018. Translated by Derek Butcher.
Derek Butcher ... "The latest to come out of Mexico is that they still persist in treating them as Viridantha at genus level and not sub-genus level. However they have produced a very comprehensive paper on the subject (In Spanish!). It is an interesting group and several are being grown in Australia. The species are not easy to recognise but the new key gives a different approach to identification. You may notice that T. yagulensis has been promoted to species level from being a variety of T. atroviridipetala. You may also notice the new T. rzedowskiana but I haven't a clue as to its pronunciation !"

1.Rosettes irregular in general outline or sickle shaped => 2
1.Rosettes spherical in general outline => 6

2.Inflorescence compound => boqueronensis
2.Inflorescence simple => 3

3.Rosettes sickle shaped, leaves curved => 4
3.Rosettes irregular, leaves scaled => 5

4.Plants usually greater than 5.1 cm high; peduncle more than 2.1 cm long => curvifolia
4. Plants usually less than 5 cm high; peduncle less than 2.1 cm long. => penascoensis

5. Peduncle more than 4.l cm long and less than 2mm diam => tortilis
5. Peduncle less than 4 cm ong and more than 4 mm diam => lepidosepala

6. Peduncle more than 4.1 cm long. => 7
6.Peduncle less than 4 cm long. => 9

7. Inflorescence with a single spike, more than 3.1 cm long, applanate to cylindrical, rarely with 2 shorter lateral spikes and adpressed to the principal => ignesiae
7. Inflorescence with 2 or more spikes, less than 3 cm long applanate => 8

8. Width of leaf at base larger than 2.1 mm; floral bracts triangular to ovate, carinate for entire length abaxially => plumosa
8. Width of leaf at base less than 2 mm; floral bracts elliptic-oblong, carinate only from centre to tip abaxially => caballosensis

9. Leaf blade more than 7.1 mm wide; anthers generally black => mauryana
9. Leaf blade less than 7 mm wide; anthers green to browner => 10

10. Plant short caulescent; floral bracts elliptic => yagulensis
10. Plant acaulis; floral bracts ovate to amply ovate, lanceolate or triangular => 11

11. Spike more than 3.1 cm long and more than 1 cm wide => 12
11. Spike less than 3 cm long and less than 1 cm wide => 13

12. Leaf sheath amply ovate to oblong, blade more than 4 mm wide, sepals less than 1.6 cm => rzedowskiana
12. Leaf sheath closely oblong, blade less than 4 mm wide; larger of the sepals to 1.5 cm => grandispica

13. Leaf blade more than 4 mm wide; spikes generally less than 3; floral bracts less than 1.5 cm long => teloloapanensis
13. Leaf blade less than 4 mm wide; spikes generally more than 3; floral bracts more than 1.5 cm long => atroviridipetala

Updated 06/06/19