This practice is applied rigidly in Europe, laxly in Australia and very laxly in the USA. In Europe the plant trade demands quality and a likeness in quantity. In Australia and the USA the trend has been for quantity with little care for quality. This trend must be reversed before we are totally swamped by lots of similar looking mediocre plants.
Don Beadle's 'Bromeliad Cultivar Registry' was released at the Houston Conference in July 1998. He had been seeking descriptions of all named cultivars but was not getting much response from American hybridists. So you will not see unnamed formulas in this list. At least, this is one attempt to encourage naming and culling of hybrids. Perhaps, in time, we may see plants with just a formula on the label being banned from competition sections adding further pressure on the hybridist to do the right thing.
Because of the downgrading of formulae, I have been trying to link names of worthwhile plants to a formula. One very popular Vriesea that I read about in competitions is Vriesea 'Poelmanii' x saundersii. Sometimes it is written saundersii x 'Poelmanii' but the plants and inflorescences seem the same.
In the BSI Journal, 1996, page 11 in an article on Bromeliad Breeding in Belgium, Dr Gilbert Samyn said that V. 'Poelmanii' x saundersii was 'Ingrid', a hybrid done in 1965. In the same article he advised that V 'Natasha' (not Natascha nor Natacha) is V. 'Poelmanii' x fenestralis and that a chimeric sprout was selected as 'Elfi'.
This seems to be the correct situation and not that advised one year earlier in the BSI Journal, 1995, pg 99 on 'Vriesea Hybrids of Today and Yesteryear' based on the Adelaide Conference paper by Dr Samyn. Here it was said that V. 'Elfi' was V. 'Viminalis Rex' x V. gigantea and V. 'Ingrid' was a chimerical and variegated selection of V. Natascha (note the spelling)! At that time I knew that V. 'Elfi' was variegated and even had a photograph showing a variegated plant entitled V. 'Poelmanii' x fenestralis (mutant) but did not notice the error in Dr Samyn's paper. Perhaps I was too concerned about finding out what chimerical meant only to discover its definition included variegated plants.
Did Dr Samyn accept the parentage of 'Elfi' as stated in Beadle's 'Preliminary Listing of all Known Cultivars and Grex Names for the Bromeliaceae', published in 1991 as I did? All who have this publication should amend the parentage of 'Elfi' to V 'Poelmanii' x .V. fenestralis with a note that this plant is variegated. The parents of V. 'Ingrid' should be noted as V. 'Poelmanii' x V saundersii.
Finally, I have been assured that 'Elfi' is not stable and you can get variegated and non-variegated forms. The non-variegated form bears little relationship to V 'Natasha' which is a bit confusing but because 'Elfi' is the name given to the variegated form, I suggest we call the other one 'Elfi Green'."