Before the fertile C.G. White halfbreds became widely available, many hybridizers struggled to break the fertility barriers that then existed in the world of arilbreds. Occasionally, someone succeeded and some of those breakthrough breeders were widely used. 

When the C.G. White amphidiploids came on the scene and hybridizers realized that they constituted a new fertile family, they became the foundation on which a new artificial species was developed (the one we now call halfbreds) and the older breeders went out of fashion. Some justifiably so, but others were merely lost in the excitement of the transition period. The ones for which additional information is available have clickable links.

ARDRUN (H.M. McLeod, 1954). Blend of rose-purple and mulberry shades from Artemis X Gudrun that was counted as a 44-chromosome amphidiploid. It appears to be the source of the korolkowii-type growth pattern of modern arilbreds, introduced to the lines of many different hybridizers through ESTHER, THE QUEEN.  Even though ARDRUN now has had more descendants introduced than most of the C.G. White amphidiploids, its potential has still not been fully explored. 

BENJAMIN (Sir Cedric Morris, 1950). Blend of lime-green and shades of purple. A regelia-pogon-dwarf hybrid from I. stolonifera x yellow chamaeiris, counted as a 42-chromosome amphidiploid and reportedly fertile, but no registered offspring.

CAPITOLA (Frank Reinelt, 1940). From William Mohr X Ib-Mac., so it should have a full complement of I. gatesii chrom0somes from William Mohr and a full complement of I. iberica chromosomes from Ib-Mac.   It has been counted as having 43 chromosomes instead of the expected 44, but it does function much like an amphidiploid. Highly pollen fertile, it pods reluctantly. Included here because although some of its descendants have contributed to the halfbred gene pool, most of its registered offspring are quarterbreds and I do believe that its full potential as a parent remains unexplored. 

CONGRES (Cayeaux, 1924). No description available, the only known pedigree is "RC x Bearded", but it was counted as having 46 chromosomes and has proven fertile. It's only registered offspring are quarterbreds: CARIBBEAN SKY and LUNAR MIST, both introduced in 1953. If CONGRES survives, it should have significant potential for improving the gardenability of modern halfbreds.

HOOGIMAC (Eugene Sundt, 1960). Spotless X Ib-Mac. S campanula violet; F spectrum violet, deep violet at tip of near-white beard. Tell, 1960. Reportedly fertile, and counted as a 46-chromosome amphidiploid, but it has no registered offspring.  Its pod parent is half I. hoogiana, so HOOGIMAC has one full set of hoogiana chromosomes and one full set of iberica chromosomes. 

IB-MAC (C. G. Van Tubergen, 1910). A 44-chromosome amphidiploid from I. iberica  X I. macrantha, one of the most important early breeders with many registered offspring. Most, however, were quarterbreds - although some served as conduits for I. iberica genes to take their place in today's gene pool. 

IFTAH EL-BAB (David Flesh, 1963). Kalifa Abra X CGW F-2. S erythrite red, veined oxblood, F deeper, patterned deep maroon, bronzy brown beard. Reportedly a 44-chromosome amphidiploid, a second-generation product of C. G. White's lines, with no registered offspring.

ISMALI (Sir Michael Foster, 1909). From I. iberica X I. pallida, counted as a 46-chromosome amphidiploid so should be as fertile as Ib-Mac and if it survives should provide the same advantage of producing gametes with a full complement of I. iberica chromosomes.  No registered offspring.

KOROLCYP (Louis A. Denis, 1923). No description available, from I. korolkowii X I. cypriana, counted as a 46-chromosome amphidiploid. No registered offspring.

LADY LILFORD (Sir Michael Foster, 1916). Blue-toned white blended with darker tones of blue. I. paradoxa X I. pallida. Counted as a 46-chromosome amphidiploid. Only two offspring were introduced, both quarterbreds:

RIC-IB (Louis A. Denis, bef.1923). Ricardi X I. iberica.  Counted as a 46-chromosome amphidiploid, but noted as obsolete in '39 CL. No other information available.  IF this survives, it should be of value in producing iberica-like arilbreds.

SHARKSIANA (Earl Roberts, 1959). S white; F white with chartreuse lines; orange-yellow beard. Sharkskin X I. susiana.Counted as a 44-chromosome amphidiploid, no registered offspring.

SPOTLESS (Jacob Sass, 1939). White self from I. hoogiana X Elf Queen. Counted as having 42 chromosomes. Only one registered offspring: HOOGIMAC (Eugene Sundt, 1960), which has campanula violet standards and spectrum violet falls with deep violet signal patch at the tip of a near-white beard. 

ZWANENBURG (Louis A. Denis, 1912). Yellow-toned blend from Lutescens aurea X I. susiana. Counted as a 40-chromosome amphidiploid. All registered offspring are quarterbreds, but could theoretically give fertile seedlings if paired with a compatible amphidiploid.