Sorbus rushforthii McAll.

This species is named in honour of Keith Rushforth, whose long-standing interest in Sorbus has led to the introduction of many interesting taxa, by no means all of which have been named. He has collected it (and other similar but probably distinct microspecies) on several occasions in the area of southern Tibet north of the great bend in the Yarlung Tsangpo, but the type collection was made in company with Hugh McAllister, from near Pasum Tso (the ‘Turquoise Lake’). The young trees in cultivation have so far fruited every year and seem to be similar in horticultural qualities to related species. Their performance as mature trees for comparison with earlier introductions will be assessed over the next few years. It is interesting that each of Rushforth’s collections from five locations (Milling, Pé, Gyala, Nyima La and Showa) lying within about 80 km of the top of the Yarlung Tsangpo Gorge seems to represent a different microspecies, that from Showa being particularly notable in having very numerous leaflets like S. parvifructa (which grows in the same valley).