Two hen and chickens ferns

New Zealand has both wild and cultivated hen and chickens ferns. Dr Leon Perrie from Te Papa explains how to differentiate between the native plant and the hybrid.

Jargon alert: Dimorphism is the occurrence of 2 different forms of leaves on the same plant.

Point of interest: What differences did Leon find between the cultivated and the wild hen and chickens fern? What characteristic suggested it might be a hybrid?

Transcript

DR LEON PERRIE

It’s long been known that the hen and chickens ferns that are cultivated here in New Zealand are different from the plants of hen and chickens ferns that you can find in the wild. Here, we’ve got the hen and chickens fern – this is Asplenium bulbiferum – and here we have got the cultivated hen and chickens fern, what we have called Asplenium lucrosum.

They are fairly easy to tell apart once you get your eye in, because Asplenium lucrosum –cultivated hen and chickens fern – when it’s trying to make spores, the frond segments are very narrow, whereas on the same plant, you get fronds which are not trying to make spores and the frond segments are quite wide. So you get these 2 forms on the same plant, this dimorphism. That doesn’t occur in the genuine true hen and chickens ferns Asplenium bulbiferum. It looks the same whether it’s making spores or not making spores.

And it was also known that the spores of the cultivated hen and chickens plants were abnormally formed. So if you looked at them down a microscope, we could see that they were misshapen – they hadn’t formed properly compared to the spores of wild hen and chickens plants. That told us that the cultivated plants were different. With the aborted spores, the abnormally formed spores, that suggested to us that these plants were hybrids of some kind, because fern hybrids usually have abnormally formed spores.

Acknowledgement: Museum of New Zealand Te Papa Tongarewa