The Aril Society Checklist

 by Tom Waters

When I'm not writing blog posts, one of my many other iris-related activities is serving as checklist editor for the Aril Society International. I've just completed the 2023 update of the checklist, which is available on the ASI website. It occurred to me that there are probably many people who are not aware that the ASI maintains a checklist of aril and arilbred irises, nor aware of what it offers beyond other references. So I thought I would use this blog post to have a look at the checklist and why it is important.

When the Aril Society International was formed in the 1950s, there were no standardized definitions for the various types of aril and arilbred irises. Irises with oncocyclus or Regelia ancestry were registered with the American Iris Society under a bewildering range of classification codes. One of the first tasks of the new society was to sort through all the various registrations and establish specific categories for them. A persistent problem in the early years was that irises of 1/8, 1/16, or even less aril ancestry were being given awards as arilbreds despite being indistinguishable from TBs. The society addressed this by requiring irises to be 1/4 aril or more to be considered as arilbreds. Subsequently, there were two separate award systems created: one for arilbreds of 1/4 to 1/2 aril content, and another for irises of 1/2 aril content or more.

'Loudmouth' (Rich, 1970) won the
C. G. White Award as an OB (1/2 aril)
but is now an OB- (less than 1/2) 
because of a change in definition.

The checklist was critical for establishing which irises met the various award criteria. The editor would take the registration data, do pedigree research, consider an iris's appearance, breeding behavior, and any chromosome counts that had been done, and then assign it to the appropriate category. In days before the internet, the ASI checklist was the only source of this classification information, because it was impractical to reprint the American Iris Society checklists to give updated classifications for arilbreds. The classifications and definitions used by the Aril Society have changed several times over the years, and the checklist is the only authoritative reference on how definition changes have affected the classification of each arilbred iris. Applying the current definitions, which involve estimating the chromosome makeup of each cultivar, is not a trivial matter in some cases.

Here are some of the things you will find in the ASI checklist that may not be presented accurately (or at all) in other sources:

Classification Information. Each iris listed, even historic irises registered long ago under other definitions, are assigned to the current ASI classification, to the extent possible given the existing information. This is of particular value to show classification committees in regions where arils and arilbreds are likely to be exhibited. It is especially important for irises that were once considered arilbreds, but no longer meet the definitions of that class.

Height Categories. In 2018, the ASI established definitions for two height categories for smaller arilbreds: arilbred dwarf (ABD) and arilbred median (ABM). These are included in the current edition of the AIS Judges' Handbook. The checklist gives the correct height category for each arilbred listed.

Chromosome Configuration. Aril and arilbred irises may include chromosome sets from oncocyclus, Regelia, tall bearded, and dwarf bearded species. Which chromosome sets are present in a given iris is of considerable interest to hybridizers, as it affects fertility and helps the hybridizer properly classify any resulting seedlings. The checklist provides the most likely chromosome configuration for most irises listed, along with an actual chromosome count where one has been reported.

Fertility Observations. When an iris is known to have produced offspring as a seed parent or pollen parent, this is noted in the checklist.

Is this 'Bronze Beauty',
'Hoogiana Bronze Beauty',
Iris hoogiana 'Bronze Beauty',
'Bronze Beauty Van Tubergen',
or 'Antiope'? Answer: yes.

Irises Not Eligible for Awards as Arilbreds. An appendix to the checklist provides a thorough listing
of irises that do not qualify as arilbreds for various reasons: never having been registered, having been registered in a non-arilbred class, or having been disqualified as definitions became more strict.

Nonregistered Aril Hybrids. A substantial number of aril hybrids have been introduced, particularly through the firm of Van Tubergen in the Netherlands, that were never registered with the American Iris Society. Some were registered with the Dutch registration authority for bulb irises, while others were simply not registered at all. The checklist includes these in an appendix, along with photographs and other information.

Even today, where so much information seems just clicks away on the internet, the ASI checklist fills an important role in providing authoritative information that is not reliably available elsewhere. It is an important resource for judges, show officials, and hybridizers. Anyone with an interest in aril and arilbred irises should become familiar with what the checklist has to offer.

Arilpums Are Here!

by Tom Waters

When I last wrote about my progress with hybridizing arilpums in September, I was eagerly anticipating this spring's bloom, with many new seedlings expected to bloom on established plants. I was not disappointed!

Aladdin's Gem

First, a little recap. Arilpums are hybrids between pure arils and the dwarf bearded species Iris pumila. When a tetraploid aril is used as the aril parent, theory predicts that the arilpum seedlings will be fully fertile amphidiploids. Historically, most arilbred dwarfs and medians have been produced by using arilbreds, diploid arils, and SDBs in various combinations, and the result has been infertile offspring, making it impossible to linebreed the smaller arilbreds to refine them and extend their potential. Arilpums are the way out of that difficulty. However, only a few have been registered and introduced: 'Barbarella' (Mathes, 1991), 'Aladdin's Gem' (Thoolen, 2002), and 'Topaz Talisman' (Jensen, 2015). Although producing fertile pollen, arilpums so far have shown little or no pod fertility, a disappointing setback.

Last spring, I had some luck with the two arilpum seedlings I bloomed, Q025-01, 'Merlin's Magic' X Armenian pumila seedling, and Q053-01, 'Tadzhiki Bandit' X 'Sudden Butterflies'. Both produced seeds for me, as did a seedling of George Hildenbrandt's, GH-11-4-2, 'Dunshanbe' X 'Hidden Dragon'. So it seemed there was hope after all for creating a line of fertile arilpums!

This spring reinforced my optimisim, and also gave a preview of the great variety of color, pattern, and form that is possible with arilpums.

Q068-14

Q068-04, with "monster beards"

Earliest to bloom were seedlings from cross Q068, 'Dunshanbe' X 'Wild Whispers'. I had over a dozen of these, most dark violet selfs with some aril look but without much distinctiveness. Two stood out, however. Q068-04 has massive caterpillar beards. Not exactly beautiful, but certainly memorable. Q068-09 is the best of the lot, with a clean oncocyclus shape and elegant look. 

Q068-09, the standout

The second cross to bloom was really exciting: Q066, 'Tadzhiki Bandit' X Caucasus pumila seedling. These were much smaller and more varied than the 'Dunshanbe' seedlings, showing many exciting colors and patterns. I've kept almost everything from this cross for further evaluation.

Q066-06

Q066-02

There was another from cross Q053, looking almost the same as its sibling that bloomed last year. I also had a few seedlings from cross Q070, 'Vera' X 'Royal Wonder', one of which was deemed worthy of a closer look.

Q070-01

I made a number of crosses with this year's arilpums, but was not very systematic or thorough about it. Seeds have not been harvested yet, so it is premature to say much about their pod fertility. But there are pods, even some bee pods, so I am optimistic. 

It's been about ten years work to get to this point, but at last I have a small cadre of arilpum seedlings to work with, and the future looks very promising.

Progress with Arilpums

by Tom Waters

When I wrote my previous blog post on arilpums early in 2019, I had to focus mostly on history and theory, as I did not yet have much to show from my own seedlings. That has now changed, and the current state of this project is even better than I had dared hope.

As explained in the previous post, arilpums are arilbreds dwarfs that come from crossing pure arils with the dwarf bearded species Iris pumila. If the aril parent is a tetraploid, theory says the resulting arilpums should be fertile amphidiploids, a sort of arilbred analog of the SDBs. They thus have the potential of ushering in a whole new "fertile family" of miniature arilbreds.

Waters Q025-01

This spring, I bloomed two arilpum seedlings, both prolific two-year-old clumps covered in bloom. The first, Q025-01, from 'Merlin's Magic' (a selection of Iris stolonifera) x P002-05, a pumila seedling of Armenian origin, has a dainty Regelia look and some nice veining. The second seedling, Q053-01, from 'Tadzhiki Bandit' x 'Sudden Butterflies' is larger and huskier, with flowers reminiscent of tall arilbreds with Regelia ancestry, such as 'Stars Over Chicago' or 'Saffron Charm'.

I also had good bloom this year on an arilpum seedling from

Waters Q053-01

George Hildenbrandt, GH-11-4-2, from 'Dunshanbe' x 'Hidden Dragon'. This is a charming dark arilpum with nice aril-like flower form.

Hildenbrandt GH-11-4-2

The remarkable thing is that all three of these seedling produced seed for me this year when crossed with other arilpums. In my previous post, I mentioned that earlier hybridizers working with arilpums had found them to be infertile as pod parents. That is clearly (and thankfully!) not a general rule! Here are my successful arilpum x arilpum crosses this year:

Q053-01 x Aladdin's Gem gave 38 seeds

Q025-01 x Q053-01 gave 9 seeds

GH-11-4-2 x Q053-01 gave 23 seeds

GH-11-4-2 x Aladdin's Gem gave 3 seeds

These are not huge seed yields, but they are certainly adequate for continued breeding. I am quite optimistic that a number of the second-generation seedlings from these crosses will be fully fertile, and it will be possible to line breed arilpums without having to constantly go back to the difficult aril x pumila initial cross. This will also open up arilpum breeding for hybridizers who live in areas where either arils or pumila are difficult to grow.

Next spring should offer even more excitement, as I have more than 30 arilpum seedlings from various crosses that will be blooming as two-year-old plants. I got a sneak preview of one this spring,  Q066-08, from 'Tadzhiki Bandit' x P018-02, a pumila seedling originating from the Caucasus mountains. It looks for all the world like a miniature rendition of its aril pod parent, giving a rather more "onco" impression than others mentioned in this post. It has not yet been tested for fertility.

Waters Q066-08

All this has been an exciting vindication of a breeding project motivated mostly by theoretic possibilities rather than concrete experience. I'm now confident that arilpums have a bright future ahead.

Arilpums: Fertile Arilbred Dwarfs!

by Tom Waters

'Aladdin's Gem' (Thoolen, 2002)
OGB/ABD

Most arilbred medians are produced by crossing standard dwarfs (SDBs) with fertile halfbreds (OGB). The results of such crosses tend to be pleasing garden subjects, occupying about the same niche as intermediates (IBs), but with the added interest of arilbred color patterns. Unfortunately, arilbred medians produced this way are usually infertile, or have very limited fertility at best. Also, being only ¼ aril (OGB-), they don’t always show enough pronounced aril characteristics to really stand out as arilbreds.

For those of us who enjoy the smaller arilbreds, the holy grail would be diminutive fertile arilbreds that are half aril in content. We might imagine miniaturized versions of the taller arilbreds that have come from breeding arils with tall bearded (TBs). One approach to realizing this dream is through the creation of “arilpums”: hybrids between arils and the tiny dwarf bearded species Iris pumila. This type of cross produces true arilbred dwarfs, around 10-12 inches (25-30 cm) in height, fertile, and half aril. Additionally, Iris pumila is expected to confer winter hardiness on its seedlings.

The potential of such breeding was first appreciated in the mid 20^th century, when iris breeders became aware of the cytogenetics of irises, and the possibility of creating “fertile families” of irises from wide crosses, if the parents are chosen to have the right chromosome configurations to produce fertile offspring. Both the SDBs (from TBs crossed with Iris pumila) and the fertile arilbreds (from TBs crossed with arils) are examples of such fertile families, and show how varied and successful they can be.

The most direct way to build a fertile family of arilpums is to cross Iris pumila with tetraploid arils. In nature, the only tetraploid arils are the Regelia species Iris hoogiana and Iris stolonifera. Indeed, the pioneering hybridizer Paul Cook (who also introduced the first SDBs from TB x pumila crosses) produced two hoogiana/pumila hybrids in the 1950s: ‘Hoogpum Blue’ (Cook, 1956) and ‘Hoogpum Purple’ (Cook, 1956). Both were fertile, but Iris hoogiana doesn’t have many characteristics that most of us think of as epitomizing the “aril look”, and these little offspring were not very distinguishable from MDBs, and in fact were registered as such.

The first approach to arilpums with oncocyclus ancestry came from Peter Werckmeister, the great expositor of cytogenetic theory to English-speaking irisarians. In the 1970s, he produced “Miltonia” (not registered) from a lucky cross, in which the aril parent (an oncogelia from ‘Teucros’ x Iris susiana), although a diploid, acted as a tetraploid by producing an unreduced gamete. Werckmeister reported eventually creating a whole array of fertile arilpums from “Miltonia”. Alas, they were not widely distributed and are now lost to us.

Thoolen arilpum seedling AP9007-1

Interest in arilpums underwent something of a revival in the 1990s, after Samuel Norris and John Holden created a line of tetraploid oncogelias from using colchicine treatment. Crossing these with Iris pumila produced arilpums with much more “onco look” than had been possible previously. The first of these to be introduced was ‘Barbarella’ (Mathes, 1991), followed by ‘Aladdin’s Gem’ (Thoolen, 2002). Both Harald Mathes and Francesca Thoolen raised a number of different arilpum seedlings, but these were the only two registered and introduced into commerce. Both ‘Barbarella’ and ‘Aladdin’s Gem’ produce fertile pollen, but are unwilling pod parents. Mathes and Thoolen noted similar difficulties with their other arilpums, and their breeding programs were eventually abandoned.

The lack of pod fertility was an unfortunate setback, because the simplest way to build up this family would be to cross the existing arilpums among themselves, rather than repeating the initial aril x pumila crosses.

'Topaz Talisman' (Jensen, 2015)
RB/ABD

The most recent arilpum is the lovely stolonifera/pumila hybrid ‘Topaz Talisman’ (Jensen, 2015). It has not yet been tested extensively for pod fertility.

Why has this family not made more progress? It has been more half a century since its potential was first understood, theoretically. I do not believe the pod fertility issue is insurmountable, although it is a setback and perhaps kept the family from taking off in the 1990s, when interest was greatest. Since then, the number of hybridizers working with arilbreds has declined, and not all are interested in such an experimental project. The parent plants, tetraploid arils and Iris pumila, are not easy to grow in all locations: the arils need a very dry summer, and pumila needs a cold winter.

Another obstacle is that the initial crosses are difficult, not many viable seeds are produced, germination is poor, and so a lot of persistence is needed to bring arilpum seedlings to bloom. Since I began working in this area six years ago, I have made 365 pollinations, resulting in 525 seeds, and at long last four seedlings which I hope to see bloom this year or next.

I would love to see others get involved; the prospects for eventual success obviously depend on a number of people working with determination over the course of a number of years. Here is the recipe:

1. Acquire tetraploid arils, such as Iris stolonifera, ‘Tadzhiki Bandit’, ‘Tadzhiki Eclipse’, ‘Werckmeister’s Beauty’, ‘Balalaika Music’, and ‘Dunshanbe’. Keep in mind that you must use tetraploid arils – crossing Iris pumila with random arils and arilbreds offers no special hope of fertility in the seedlings.
2. Acquire Iris pumila, either from seed exchanges, or named cultivars such as ‘Royal Wonder’, ‘Wild Whispers’, ‘Little Drummer Boy’, ‘Hobbit’, and others.
3. Make crosses between these two groups, as often as possible, and mixing and matching parents as much as possible.
4. Also get any available arilpums (pretty much just ‘Aladdin’s Gem’ and ‘Topaz Talisman’ these days), to cross amongst themselves or with arilpum seedlings you produced from the aril/pumila crosses.

Hildebrandt arilpum seedling 11-4-2
(photo: George Hildebrandt)

I think this a project that offers enormous potential in the long term, and is ideal for a small, backyard hybridizer who does not have the resources to grow thousands of seedlings and does not need to worry about immediate commercial success. There is a whole new world waiting to be opened up!

An Arilbred Iris Sampler

Tom Waters

'Oyez' (White, 1938)

I was recently contacted by an iris lover who had read my blog post on the classification of arilbred irises and wanted to sample each of the categories. She asked if I had any recommendations. I gave a few off the top of my head, and she suggested that this might make a good blog topic. I agree! So here is my arilbred sampler, for those who want to try the full range of different types of arilbreds.

I've restricted the irises mentioned here to those that are readily available. The commercial gardens that have the best selection of arilbreds are Superstition Iris Gardens, Mid-America Garden, and Blue J Iris. In addition, the Aril Society International has an annual plant sale with many more arilbreds than these commercial growers offer. The offerings vary each year depending on what members contribute, but many varieties are offered nearly every year. If an iris was available from one of the three large commercial growers in their most recent catalog, or in the ASI plant sales for the last two years, I deemed it readily available. Some other commercial growers list a small number of arilbreds, and if arilbreds are grown in your area, the local iris society plant sales can also be a good source of plants.

I want to be clear that this listing is indeed intended as a "sampler". The idea is to cover as many different kinds as possible, to showcase the diversity of arilbreds. It is not an attempt to identify the "best arilbreds" by some objective criteria, nor even a list of "Tom's favorites". The idea is that if you are new to arilbreds, and plant a varied assortment, you can discover your own preferences and what grows well for you.

The ASI recognizes nine different categories of arilbred, based on the type and amount of aril content the iris has. There are two types of pure arils: oncocyclus and Regelia. An arilbred can have either or both of these types of aril in its background. Hence we have oncobreds (OB), Regeliabreds (RB), and oncogeliabreds (OGB, mixed onco and Regelia content). Furthermore, arilbreds can be half aril, more than half aril, or less than half aril. Those with more than half aril content are indicated with a "+" sign; those with less than half aril with a "-" sign. No sign is used for those that are half aril. Thus RB+ means an arilbred whose type of aril content is Regelia only, and whose amount of aril content is more than half.

It turns out that these nine categories actually allow for more distinctions than a practical gardener need attend to. There are very few OB arilbreds, and they are indistinguishable from most OGB types. The reason is that most of today's arilbreds are descended from pioneering work by C. G. White in the 1940s, and White did not keep track of parentages during this time. So his arilbreds, although drawing heavily on oncocyclus arils and selected to resemble oncocyclus as much as possible, are classified as OGB because of the possibility of some Regelia ancestry. So I don't separate OBs from OGBs here.

I do, however, separate out the arilbred medians and arilbred dwarfs from the tall arilbreds. These smaller arilbreds, typically with dwarf or median bearded irises in their parentage, fill a very different role in the garden and provide much of the diversity to be encountered in the arilbred tribe.

So much for the preliminaries. Onward to the plants!

OGB and OB (Onco-type halfbreds)

These are what most of us think of when we think of arilbreds. Most are tall types, with TB and oncocyclus ancestry dominating. Blooms are typically large and globular, often with strong aril markings, such as signal spots or veining.

'Refiner's Fire' (McGrath, 2007)

Large bold signals are actually a rather recent development in this group, with 'Energizer' (Shockey, 1996) being a striking breakthrough in its time. More recently, 'Noble Warrior' (Tasco, 2006) combines a dramatic signal with a bit of veining. 'Refiner's Fire' (McGrath, 2007) gives a striking dark signal on a deeply colored red-toned flower.

'Sand Dancer' (Tasco, 2010) gives us a whole different look, with falls covered in peppery stippling. Yet another completely different look is to be found in 'Navajo Velvet' (McAllister, 2009), with falls of lustrous, satiny mahogany red.

The historic arilbred 'Oyez' (White, 1938) has seduced many iris growers into the arilbred world with its dramatic precise veining. Strangely, it has been difficult to reproduce this striking pattern in modern arilbreds. ('Oyez' is a sterile diploid.) An early success was 'Jonnye's Magic' (Rich, 1992). For a true modern advancement in veined arilbreds, seek out 'Alakazam' (Tasco, 2013).

'Aladdin's Gem' (Thoolen, 2002)

There are few arilbred medians and arilbred dwarfs in this category. Very notable is 'Aladdin's Gem' (Thoolen, 2002), a fertile aril-pumila hybrid about the size of a small SDB (standard dwarf bearded)!

OGB- and OB- (Onco-type quarterbreds)

Originally, these categories were dominated by tall arilbreds that came from crossing halfbreds with TBs. At a time when halbreds were uncommon and difficult to grow, the quarterbreds were the most accessible arilbreds for most gardeners. The historic iris 'Elmohr' (Loomis-Long, 1942) was a fine example of the type, the only arilbred to win the Dykes Medal. It does not show the strong aril patterning we now expect in arilbreds, without signal or veining to speak of. To understand its allure, we must think back to a time when TBs were troubled with narrow petals and often droopy form. 'Elmohr' stood out with dramatically large blooms, wide falls, and a bit of globular onco form to bring it all together.

Some other tall quarterbreds for the sampler are 'Dune' (Hager, 1981) and the very recent 'Heart of Hearts' (Black, 2015). At their best, this type of iris can bring some of the modern TB form and bud count into irises that still evoke their aril ancestry.

'Desert Snow' (Black, 2013)

Since the 1970s, however, arilbred medians have increasingly dominated these categories. Crossing an
OGB halfbred with an SDB produces an OGB- arilbred median. In the garden, these occupy a niche similar to the IBs (intermediate beardeds), but with some aril traits to give them that special something extra. The charm and adaptability of this type of arilbred has given them a great appeal among arilbred growers and median fanciers alike. 'Brash and Bold' (Black, 2009) and 'Desert Snow' (Black, 2013) are fine examplars of what this category has to offer.

A somewhat different approach is found in 'Persian Sapphire' (Baumunk, 2005), a child of 'Aladdin's Gem' that has more Iris pumila in its makeup than TB.

There are some arilbred dwarfs in this category that are worthy of attention. 'Loudmouth' (Rich, 1970) is a perennial favorite, SDB-sized with raucous signal and veining and globular form. 'Tiny Pirate' (Rich, 1990) is the most diminutive arilbred I have grown; it would be small even among MDBs (miniature dwarf beardeds), but struts onco form, a signal, and a whisper of veining.

RB (Regelia-type halfbreds)

Enthusiasm for large, globular oncocylcus irises with their dramatic signals and stippling was a driving force in early arilbred breeding. The Regelias took a back seat in the minds of many growers and breeders; sometimes they were thought of as providing nothing but some ruggedness and climate adaptability. But some have always appreciated the Regelias for their svelte elegance, sometimes striking veining, satiny texture, or blended colors.

An early Regeliabred that helped draw attention to the potential of this type of iris was 'Genetic Artist' (H. Danielson, 1972). This shows a classic color pattern derived from the Regelia Iris stolonifera: a yellowish rim around a blue or violet center. 'Afrosiab' (Volfovich-Moler, 2001) shows a touch of ruffling from its TB parent, 'Mary Frances' (Gaulter, 1973). The French hybridizer Lawrence Ransom worked extensively with Regeliabreds, with his 'Eastern Blush' (Ransom, 2002) being much used in his breeding program.

RB- (Regelia-type quarterbreds)

Ransom's work takes center stage in this category. Among the tall RB- are the horned 'Sandthorn' (Ransom, 2011), and his "Pashtun" series, for example 'Pashtun Princess' (Ransom, 2011).

Ransom also produced a delightfully varied series of RB- arilbred medians, the "Vera girls", from crossing the Regelia 'Vera' (Van Tubergen, not registered) with SDBs.of which 'Vera-Marina'  (Ransom, 1998) is one example.

OGB+ (Onco-type "three-quarter"-breds)

This group has become sadly scarce in commerce, with seldom any new ones registered and introduced. This is perhaps because few arilbred hybridizers today grow the oncocyclus species and hybrids needed to produce this type of arilbred, which usually comes from crossing an OGB arilbred with a pure oncocyclus. The few that are readily available are not always representative of the best this type of breeding has to offer. 'Tul Kerem' (H. Danielson, 1974) is interesting but I find its combination of oncocylcus and Regelia traits ends up not doing justice to either. 'Masada's Glory' (Whitely, 2002) is a better exemplar of what this category has to offer. Although they do not meet my availability criteria, keep a look out from 'Jeweled Veil' (Rich, 1978) or 'Dotted Sunsuit' (Mathes, 2001). These show the oncocyclus features of their ancestry to best advantage.

RB+ (Regelia-type "three-quarter"-breds)

'Turkish Topaz' (Austin, 1962)

A couple oddities round out the sampler. 'Turkish Topaz' (Austin, 1962) was registered as a pure Regelia hybrid, but its parentage is somewhat ambiguous and it looks and grows like an RB+. The flowers are yellow with much brown streaking and blotching. 'White Arts' (L. Danielson, 1986) has only Iris hoogiana in its Regelia ancestry. This species shows nothing that we might recognize as distinctively aril in its coloration. If you walked by 'White Arts' in a garden, you could be forgiven for thinking it was a white IB or perhaps an antique diploid TB.

If you want to sample the world of arilbreds, be sure to try several different types. The variety available in plant size, color pattern, and form is truly remarkable!