Topic: Cultivated hen & chickens ferns
Is part of topic Hen & chickens ferns
Most hen & chickens plants in cultivation are properly called Asplenium ×lucrosum, despite usually being mislabelled as A. bulbiferum.
Asplenium ×lucrosum is a sterile hybrid between A. bulbiferum and A. dimorphum. The "×" preceding “lucrosum” indicates it is a hybrid.
The three are easily distinguished because Asplenium ×lucrosum combines the production of bulbils of A. bulbiferum with the frond dimorphism (having two forms) of A. dimorphum - the fronds with spore-producing structures are much more dissected than those without.
The two parent species – Asplenium bulbiferum and A. dimorphum – don’t occur together naturally, A. bulbiferum being naturally found only in New Zealand and A. dimorphum only on Norfolk Island. However, by 1831 both had been taken to grow in Britain. This is probably where they hybridised, producing A. ×lucrosum, which is now cultivated around the world.
1831 was when Allan Cunningham returned to England from his botanical explorations in Australasia; he is one of the few botanists to have visited both Norfolk Island and New Zealand by that early time. We know from his writings that he sent home live plants of A. dimorphum. We also know that he collected A. bulbiferum, and he may well have been responsible for its live export too.
Like many hybrids, the false hen & chickens fern is unable to reproduce sexually, its spores being abnormally formed. However, it can be propagated vegetatively via its bulbils. This is how it is produced for sale, and also how it has become a minor weed in some parts of New Zealand.
Perhaps because it has ‘hybrid vigour’ and is easier to grow, Asplenium ×lucrosum is the hen & chickens fern usually sold. The name “lucrosum” reflects its lucrative cultivation for horticulturalists dealing in ferns.
Te Papa’s herbarium holds the type specimen of Asplenium ×lucrosum.
We formally described Asplenium ×lucrosum in this publication:
Perrie LR, Shepherd LD, Brownsey PJ (2005) Asplenium ×lucrosum nothosp. nov.: a sterile hybrid widely and erroneously cultivated as “Asplenium bulbiferum”. Plant Systematics and Evolution 250: 243-257.