Naming and typification of Polystichum lonchitis × setiferum

The fern hybrid Polystichum lonchitis × setiferum was published in 1904 by Halácsy as "Aspidium lonchitiforme", apparently collected in Taygetos Mountains, Pelopponesia, Greece in 1898.

Just a single hybrid has ever been reported from Taygetos Mountains, where Polystichum aculeatum as treated nowadays seems to be absent, P. setiferum, treated by Halácsy as "aculeatum" is commonly distributed.
The author of Aspidium lochitiforme stated that A. lobatum, our P. aculeatum was absent from Peloponnesia in opposite to A. aculeatum, our P. setiferum.
Anne Sleep repeated the same situation in her doctoral thesis in 1966 after having searched for this hybrid in Taygetos Mountains without success.
Since both parental species, P. lonchitis and setiferum are present there, Sleep accepted Polystichum × lonchitiforme as valid name for the hybrid, but without cytologic examination to exclude the identic looking hybrid P. aculeatum × lonchitis, P. × illyricum.

The type material from Greece does indeed look the same as the latter hybrid, thus the only evidence that it could be lonchitis × setiferum is the apparent absence of aculeatum at Taygetos.
We may not exclude that aculeatum is or was present where the single type of A. lonchitiforme has been collected, no precise locality has been noted.
If that was not enough, Halácsy wrote to have found the single hybrid within a great number of P. lonchitis sendt by Heldreich for distribution in Herbarium graecum normale.
Probably the type originates from the Greek mountains, but i would even not exclude mixing up with sheets collected elsewhere, this way P. × illyricum might have been labelled with wrong origine.
In other words the type of A. lonchitiforme might turn out to be another synonym to P. × illyricum, so far the number of chromosomes could be testified.
This seems to be simply impossible, thus i think we will have to accept P. × lonchitiforme as binomen for P. lonchitis × setiferum, no matter if dubious or not.

The first cytologic evidence of true hybrid P. lonchitis × setiferum was done by Anne Sleep in 1976, the ferns were found in region of "Ben Bulbin" in counties Sligo and Leitrim, Ireland.

A single later report of the same hybrid came from Hungary, but the Irish occurrence seems to be the sole known present at time.
For this reason i chose the English names "Irish shield fern" and "Irish holly fern" for the hybrid.

Posted on 13 December, 2015 17:00 by erwin_pteridophilos erwin_pteridophilos


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