You may be forgiven for not understanding the Sorbus genus in the British Isles, as it is very complex. I’m producing this page to try and explain things somewhat, but this is far from exhaustive enough, but I hope it helps!
Despite the fact that several of our rare native species were described in the 18th century one almost never gets to hear about them. When you read all the old books they generally only ever list three species of Sorbus native to Britain namely: Rowan, Sorbus aucuparia L.; Whitebeam, Sorbus aria (L.) Crantz; and Wild Service Tree, Sorbus torminalis (L.) Crantz. Other books may also mention the Swedish Whitebeam, Sorbus intermedia (Ehrh.) Pers., as an introduced species. Some of the better books, especially the older ones will make reference to the Cornish Whitebeam, more recently known as the Devon Whitebeam, as that is where it was first described, for that they used the name Sorbus latifolia Syme. The really old books included the Pears (Pyrus sp.), but we won’t go there with that.
Tim Rich, Libby Houston, et al. Carried out a fantastic work back in 2010: Whitebeams, Rowans and Service Trees of Britain and Ireland (BSBI), which contained an account of all the native and naturalized Sorbus taxa occurring in Britain and Ireland, at the time numbering 44 species and eight hybrids. Of these 52 taxa, 43 were native and an astonishing 35 were endemic to Britain. Two were Irish endemics. That work demonstrated that the British Isles, and especially the Avon gorge in Bristol are the main hotspot for the Sorbus genus in the world.
The Forestry Commission, in their list of native species, tried to accommodate the variety of Whitebeams by including a Sorbus aria sensu latu (Whitebeam in the broad sense) category. However, this fails to include any of the Subgenus' (Soraria) and (Tormaria), because they’re not of the (Aria) Subgenus, and so they were not able to be FRM certified at all. Also they failed to list at all S. domestica, which is most certainly a British native species.
Moving on from this, all has changed. For Sennikov & Kurtto (2017) have published a new checklist of Sorbus s.l., which provides an updated classification of this group according to the latest phylogenetic studies. This is very comprehensive, and convincing. I’m not going to go into it in detail now. Only to say that it re-groups all of our native species into five new genera. Of their list of 201 different worldwide taxa, I have listed out below only those that occur growing wild in Great Britain & Ireland, both natives and introductions.
At Trebrown Nurseries we grow the largest selection of natives ever to be grown in Britain. But don’t grow all of these. We only really specialise in south-west (Sorbus) species, around 30 different ones, although we do grow some others from elsewhere; and then of these, many we grow only for their respected species recovery programs, of which some have no real garden or forestry merit, we generally don't list them for sale, and there seems little point in widespread planting of rare whitebeams in the wild as this detracts from understanding and solving the habitat management issues which make them rare in the first place. That said, some of these do show some merit as attractive garden shrubs, and one or two show potential for commercial forestry timber production. I provide links to the ones you may purchase on our website.
Sorbus aucuparia L., and its hybrid Sorbus × proctoriana T.C.G.Rich
Torminalis glaberrima (Gand.) Sennikov & Kurtto. (Syn. Sorbus torminalis (L.) Crantz.)
Cormus domestica (L.) Spach (Syn. Sorbus domestica L.)
Although I do question whether our Common Whitebeam fits into Aria edulis (Willd.) M.Roem., and maybe we have several that need splitting out into several species.
Aria arvonicola (P.D.Sell) Sennikov & Kurtto (Wales: Menai Strait)
Aria avonensis (T.C.G.Rich) Sennikov & Kurtto (Avon Gorge)
Aria cambrensis (M.Proctor) Sennikov & Kurtto (Wales)
Aria cheddarensis (L.Houston & Ashley Robertson) Sennikov & Kurtto (Cheddar Gorge)
Aria edulis (Willd.) M.Roem. (Syn. Sorbus aria (L.) Crantz)
Aria eminens (E.F.Warb.) Sennikov & Kurtto
Aria eminentiformis (T.C.G.Rich) Sennikov & Kurtto (Wye Valley)
Aria eminentoides (L.Houston) Sennikov & Kurtto (Somerset)
Aria evansii (T.C.G.Rich) Sennikov & Kurtto (W. Gloucestershire)
Aria greenii (T.C.G.Rich) Sennikov & Kurtto (Wales)
Aria herefordensis (D.Green) Sennikov & Kurtto (Wales)
Aria hibernica (E.F.Warb.) Sennikov & Kurtto (Ireland)
Aria lancastriensis (E.F.Warb.) Sennikov & Kurtto (Lancashire)
Aria leighensis (T.C.G.Rich) Sennikov & Kurtto (Avon Gorge)
Aria leptophylla (E.F.Warb.) Sennikov & Kurtto (Wales)
Aria margaretae (M.Proctor) Sennikov & Kurtto (SW. Somerset, N. Devon)
Aria parviloba (T.C.G.Rich) Sennikov & Kurtto (Gloucestershire: Coldwell Rocks)
Aria porrigentiformis (E.F.Warb.) Sennikov & Kurtto
Aria richii (L.Houston) Sennikov & Kurtto (N. Somerset)
Aria × robertsonii (T.C.G.Rich) Sennikov & Kurtto (Avon Gorge)
Aria rupicola (Syme) Mezhenskyj
Aria rupicoloides (L.Houston & T.C.G.Rich) Sennikov & Kurtto (Cheddar Gorge)
Aria saxicola (T.C.G.Rich) Sennikov & Kurtto (Wye Valley)
Aria spectans (L.Houston) Sennikov & Kurtto (Avon Gorge)
Aria stenophylla (M.Proctor) Sennikov & Kurtto (Wales)
Aria stirtoniana (T.C.G.Rich) Sennikov & Kurtto (Wales)
Aria vexans (E.F.Warb.) Sennikov & Kurtto (SW. Somerset, N. Devon)
Aria whiteana (T.C.G.Rich & L.Houston) Sennikov & Kurtto (Avon Gorge)
Aria wilmottiana (E.F.Warb.) Sennikov & Kurtto (Avon Gorge)
Hedlundia anglica (Hedl.) Sennikov & Kurtto (Syn. Sorbus anglica Hedl.) (SW. Ireland, W. & SW. Great Britian)
Hedlundia austriaca (Beck) Sennikov & Kurtto introduced
Hedlundia arranensis (Hedl.) Sennikov & Kurtto (Scottland: Island of Arran)
Hedlundia cuneifolia (T.C.G.Rich) Sennikov & Kurtto (Wales: near Llangollen, England: Shropshire)
Hedlundia hybrida (L.) Sennikov & Kurtto introduced
Hedlundia leyana (Wilmott) Sennikov & Kurtto (Wales: Brecon Beacons)
Hedlundia minima (Ley) Sennikov & Kurtto (Wales: Brecon Beacons)
Hedlundia motleyi (T.C.G.Rich) Sennikov & Kurtto (Wales: Brecon Beacons)
Hedlundia neopinnatifida (P.D.Sell) Sennikov & Kurtto (S. Somerset)
Hedlundia pseudofennica (E.F.Warb.) Sennikov & Kurtto (Scottland: Island of Arran)
Hedlundia pseudomeinichii (Ashley Robertson) Sennikov & Kurtto (Scottland: Island of Arran)
Hedlundia scannelliana (T.C.G.Rich) Sennikov & Kurtto (Ireland, North Kerry: Ross Island)
Hedlundia thuringiaca (Nyman) Sennikov & Kurtto
Karpatiosorbus admonitor (M.Proctor) Sennikov & Kurtto
Karpatiosorbus bristoliensis (Wilmott) Sennikov & Kurtto (Avon Gorge)
Karpatiosorbus croceocarpa (P.D.Sell) Sennikov & Kurtto introduced
Karpatiosorbus devoniensis (E.F.Warb.) Sennikov & Kurtto
Karpatiosorbus houstoniae (T.C.G.Rich) Sennikov & Kurtto
Karpatiosorbus latifolia (Lam.) Sennikov & Kurtto introduced
Karpatiosorbus sellii (T.C.G.Rich) Sennikov & Kurtto introduced
Karpatiosorbus subcuneata (Wilmott) Sennikov & Kurtto
