Two Changes of Heart

Firstly, the lime trees with hairs on the underside of the leaf veins. I went back to a 1992 paper by Donald Pigott concerning the hybrid lime trees planted in Britain in the late seventeenth and early eighteenth century.  He identifies two distinct clones one of which has lower leaves with “a few paired longer hairs lying along the sides of the main vein” and the other “scattered longer simple or paired hairs along much of the length of the main veins. In some trees there are also flat stellate hairs sparsely distributed on the underside of the lamina, and not associated with the main veins”. They are both fertile and Professor Pigott tells me “they produce individuals that vary from similarity to the parent, all stages of intermediacy to T. platyphyllos and genetic dwarfs but rarely, if ever, trees you would confuse with T. cordata .”

So Tilia x europaea coming under “Leaves hairless both sides (except for tufts in vein axils below)” in keys is simply wrong. I am reverting to Tilia x europaea for the local planted trees.

Secondly, many years ago I was persuaded that a particular type of Mimulus hybrid found here (and elsewhere) is Mimulus guttatus × nummularius × variegatus (M. x caledonicus ined.) and that is how I have been recording it.

Mimulus hybrid Geary0606

Last year Mick Crawley said “My view is that both M. variegatus and M. nummularius should be sunk within M. luteus var. rivularis and therefore that your plant is no different from M. x robertsii.”

I have now been in touch with Mario Vallejo-Marin at the University of Stirling who published details of the neo-native Mimulus peregrinus in 2012. He says, “I agree that the plant you described looks like what I call Mimulus x robertsii. Identifying the exact parentage of M. x robertsii is not a straightforward task, in part because the South American parent (the M. luteus clade with all its taxa) is a complex of interfertile species. From my observations in the UK, I gather that most of the (rare) M. luteus sensu lato that occurs in the UK is of hybrid origin. I have on my list of projects to do a detailed characterisation of M. luteus in the British isles, and perhaps then I will be more adventurous in trying to recognise different strains of M. x robertsii.”

And also: “Please keep me posted of your observations on Mimulus in Skye. I would love to hear if you find any seed-producing M. x robertsii. It could be a new sighting of M. peregrinusLocal Mimulus spotters, please note.

I am changing all VC104 records of “Mimulus guttatus × nummularius × variegatus (M. x caledonicus ined.” to M. x robertsii. They are all either recorded or determined by me so I am feeling within my rights!


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