Another World - the diverse Bigenerics

by Geoff Lawn

Bromeliad bigenerics are virtually unknown in the wild because fertility barriers, different blooming times and geographical range prevent most species in different genera from cross-breeding by specialised pollinators. Even in large cultivated mixed collections where breeders can try many combinations, there are no readily-available records on the success/failure ratio of attempts, probably because hybridists work mainly in isolation and we tend to hear only of the progeny which survived and were not culled. Certainly pollen storage assists with otherwise non-simultaneous flowering parents but the biggest obstacle to success appears to be still genetically-incompatible "partners" - the potential parents' genes simply don't mix, at least not with current plant-breeding technology.

To date(December 2002), the Bromeliad Cultivar Registry lists 279 different bigenerics within 38 genera. To be expected, every bigeneric has been produced from 2 genera within 1 sub-family, never Bromelioideae crossed with Tillandsioideae or Pitcairnioideae (or combination thereof) - their biological differences are just too great and cause rejection. It is often quoted that all bigenerics turn out sterile ("mules"), which may be true in most cases as there are no intergenerics (the next generation) involving 3 or more different genera as yet registered. Noted however are Canistrum x Aechmea x Canistrum (e.g. x Canmea 'Tropic Beauty') and Cryptanthus x Billbergia x Cryptanthus (e.g. x Cryptbergia 'Goodale'), for instance.

So far, the majority of bigenerics have been primary crosses (i.e. species x species) and those parents which are least alike tend to produce the most distinctive offspring. Dominant and recessive characteristics play a role in individual crossings, with some progeny intermediate between both parents, while other hybrids appear more like their seed parent OR pollen parent, at least at species level. The genetics are more complex with hybrid x hybrid or hybrid x species pairings, producing a mixed range of siblings even from the same seed batch. Bigeneric genera names have "X" inserted before each genus to distinguish them from standard, botanically-described genera names.

The following wide selection may have individual appeal - beautiful, bizarre, curious etc., but when studied closely they are altogether in different combinations to the standard, familiar botanical 57 genera:

Although several bigenerics date back to the 1880s, relatively few bigenerics were bred before about 1960. In fact, certain combinations were thought impossible to create, but bromeliad hybridising overall has escalated in the 42 years since and bigenerics have proliferated accordingly, despite the gene-mixing difficulties by artificial cross-pollination.

On the competitive showbench bigenerics still are placed mostly in classes worded "Any Other Genus". As their numbers and popularity increase, their own class or even a single bigeneric genus class may be warranted. After all, currently the largest bigeneric genera with sizeable cultivar numbers are: XNeomea (59), XNeotanthus (49) and XNiduregelia (33).

Other genera worth looking at, their present cultivar totals and examples are:
XAnamea (Ananas x Aechmea) = 5, e.g. x A. 'Pink Scorpion'
XAndrolaechmea (Androlepis x Aechmea) = 2, e.g. x A. 'Sampson'
XBillmea (Billbergia x Aechmea) = 6, e.g. x B. 'Red October'
XBillnelia (Billbergia x Quesnelia) = 4, e.g. x B. 'Sebastian Laruelle'
XCanegelia (Canistrum x Neoregelia) = 2, e.g. x C. 'Roman Fountain'
XCryptananas (Cryptanthus x Ananas) = 1, i.e. x C. 'Pink Utopia'
XCryptmea (Cryptanthus x Aechmea) = 1, i.e. x C. 'Dazzler'
XDeuterocairnia (Deuterocohnia x Pitcairnia) = 1. i.e. x D. 'Lenny'
XNeobergiopsis (Neoregelia x Hohenbergiopsis) = 1, i.e. x N. 'Pinegrove'
XNeorockia (Neoregelia x Wittrockia) = 1, i.e. x N. 'Midhurst'
XNeostropsis (Neoregelia x Canistropsis) = 1, i.e. x N. 'Fanfare'
XNidbergia (Nidularium x Billbergia) = 1, i.e. x N. 'Chas Hodgson'
XNidumea (Nidularium x Aechmea) = 9, e.g. x N. 'Midnight'
XOrtholarium (Orthophytum x Nidularium) = 2, e.g. x O. 'Hades'
XOrthomea (Orthophytum x Aechmea) = 2, e.g. x O. 'Powderpuff'
XOrthotanthus (Orthophytum x Cryptanthus) = 1, i.e. x O. 'Little Bits'
XPortemea (Portea x Aechmea) = 5, e.g. x P. 'Hilda Ariza'
X Pseudanamea (Pseudoananas x Aechmea) = 1, i.e. x P. 'Prima Ballerina'
X Puckia (Puya x Dyckia) = 1, i.e. x P. 'Sparkle'
XQuesistrum (Quesnelia x Canistrum) = 1, i.e. x Q. 'Claudia'
XQuesregelia (Quesnelia x Neoregelia) = 1, i.e. x Q. 'Pioneer'
XVrierauhia (Vriesea x Werauhia) = 2, e.g. x V. 'David Fuertes'

We have both gained and lost bigeneric genera through botanical reclassification of their parent genera or individual species within. For example, XPitinia (Pitcairnia x Pepinia) no longer exists because most botanists agreed that all Pepinia species be transferred back to Pitcairnia. XNidumea 'Beacon' became XAechopsis 'Beacon' when one of its parents, Nidularium burchellii, became Canistropsis burchellii. Some coined bigeneric genera names (alternate first and last syllable of both genera names combined) have had to be standardised because, for example, the combination Nidularium x Neoregelia (now XNiduregelia ) used to be called XNeolarium also.

Whatever their names, man-made bigenerics do present an unearthly appearance compared to the "normal, natural" world, albeit fertile wild species multiplying true to type but with limited hybridising on occasions within certain boundaries. The field of potential combinations of bigenerics is still wide open but will the hybridists proceed on the basis of "Quality above Quantity"---that is the question.