Plants of Skye, Raasay & The Small Isles

Several fellow-botanists (Joanna, Neil, Seth, Steve) have been looking at Cotoneasters for me, in particular those in the C. bullatus/rehderi group. I had been told that the fruit length was diagnostic and as our plants pretty much all have fruits in the 9-10(-11) mm range, I started to believe that they are all C. rehderi (Bullate Cotoneaster). This size is outside the range given for C. bullatus fruit size in all the (numerous) reference works I have consulted.

However, the petiole length, leaf sizes, both length and width, and pubescence pretty much all fit within the range of C. bullatus (Hollyberry Cotoneaster) and the keys to separate these two species in the European Garden Flora, the book Cotoneasters: A Comprehensive Guide to Shrubs for Flowers, Fruit, and Foliage, and Sell & Murrell’s Flora of Great Britain and Ireland all use leaf size and not fruit size.

So…… it seems that what we have is C. bullatus with larger than reported fruits. Seth had a discussion with a long-term professional gardener on Skye who says that C. rehderi is generally unavailable as it is not on the ‘trading circuit’ whereas C. bullatus has been for years.

During this exercise we have also found what looks to be C. lacteus (Late Cotoneaster) by a forestry track near Portree. If confirmed, this will be the first record in the wild north of the Central Belt.

Later: Not confirmed. Probably atypical C. frigidus. Later still: Now confirmed by the BSBI Cotoneaster referee as Cotoneaster serotinus (Yuletide Cotoneaster). First for Scotland!

Additionally, we have found it appropriate to have another look at Stranvaesia davidiana (Stranvaesia) as we may have it in at least one more location than currently shown on the distribution map.

And as a final twist, our friendly gardener suggests that the majority of what we think is Cotoneaster frigidus (Tree Cotoneaster) is a cultivar known as ‘Cornubia’, the main difference being that true C. frigidus is deciduous whereas ‘Cornubia’ is largely evergreen

Tags: Plants

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