Hybridizing Notes: Odm. Extraria × Oda. George McMahon

Registered in 1920, Odm. Extraria (Odm. crispum × Odm. laeve) went nowhere. But a David Stead remake at Mansell & Hatcher introduced us to the alba strain of Odm. Extraria and it is a handsome thing. Bob Hamilton secured one of the remakes and has used it cleverly. He may also have made a misstep. As Bob's missteps are rare, read on and be reminded that orchid hybridizing has many traps. The first hybrid we have bloomed a ton of is Odm. Extraria alba × Oda. (Odm. Parade × Oda. George McMahon) + Oryzalin. They are floriferous, 100% albas, shapely, with many tending greenish especially when the flowers are fresh. I became immediately fascinated with the hybrid. But....... both the diploid and tetraploid forms are not really acceptable in their flower longevity. The tetraploids last longer, of course, but still not long enough and there's little less attractive to my eye than an inflorescence that is essentially dying in the middle. Then there is the crossing pictured, Odm. Extraria alba × Oda. George McMahon where 25% come as alba yellows. Some of this cross also have flower longevity issues and some do not. So what's going on? Well it's all quite simple when you think it through. Oda. George McMahon is a fertile triploid. I suspect that the flower life of Odm. Extraria alba is not generous. So when two diploid gametes match up, the resultant diploid progeny have fairly shortlived flowers. But when Oda. George McMahon produces a n+n+n gamete and this seems to happen fairly frequently, the resulting 4n seedling has much more Oda. George McMahon influence and it lasts a much longer time. That's my rationalization of what is happening but someone who knows more about genetics may see things differently.