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Allen Coombes & Roderick Cameron (2022)
Coombes, A. & Cameron, R. (2022), 'Quercus schottkyana' from the website Trees and Shrubs Online (treesandshrubsonline.
Tree to 20 m or shrub to 6 m. Bark smooth, light brown or yellowish brown. Twigs at first covered in rust-coloured tomentum, later glabrous, greyish-green or brown. Buds ovoid, small, yellowish-green, tomentose. Leaves evergreen, 5–14 × 2–5 cm, elliptic to obovate or oblanceolate, leathery, upper surface green, lower surface glaucous with tawny tomentum on the veins and midrib, which is prominent below and impressed above, 8–12 secondary veins on each side of the midrib, margins serrated for upper two-thirds, base wedge-shaped to almost rounded, apex acuminate to caudate; petiole 0.5–2 cm long. Infructescence 1.5–2 cm long with 8–14 cupules, though only one to two mature. Petiole thin, 0.5–2 cm long, sparsely pubescent. Cupule bowl-shaped, 0.5–1.0 × 0.8–1.8 cm, outside tawny-tomentose, inside with pale brown silky hairs; scales in six to eight rings. Acorn ellipsoid to ovoid, with one-third to half of its length enclosed in the cupule, 1–1.4 cm long, ripening in the first season; stylopodium short but persistent. (Huang et al. 1999; le Hardÿ de Beaulieu & Lamant 2010).
Distribution China Guizhou, Sichuan, Yunnan
Habitat Broadleaved evergreen forests, 1500–2500 m asl, in association with Castanopsis delavayi, Keteleeria evelyniana, Quercus aliena, Q. fabri, Lithocarpus dealbatus, L. variolosus, Machilus yunnanensis, Camellia speciosa, and Pinus yunnanensis.
USDA Hardiness Zone 8
Conservation status Least concern (LC)
Taxonomic note Menitsky (2005) considers this taxon a subspecies of Q. glauca Thunb. Flora of China recognises the species as Cyclobalanopsis glaucoides, with Q. schottkyana and Q. glaucoides as synonyms (Huang et al. 1999). However, the epithet ‘glaucoides’ already exists in Quercus for a Mexican species (Q. glaucoides M. Martens & Galeotti, so named for its affinity to Q. glaucescens Bonpl.) and Q. glaucoides (Schottky) Koidzumi is a later homonym. The Chinese species must therefore be referred to as Q. schottkyana when included in Quercus.
This species is endemic to the Yunnan-Guizhou Plateau in southwestern China and is the dominant oak species in the evergreen broadleaved forests in the area. Though originally described under the epithet glaucoides for its similarity to Q. glauca, recent molecular analysis suggests it is more closely related to Q. acuta and the critically endangered Q. sichourensis (Li et al. 2021). It was not introduced to Western cultivation until 1988, but it was heralded by Grimshaw and Bayton in 2009 as a Chinese species that would rival Mexican oaks for beauty and vigour – and it is indeed now found in many collections in the UK and Europe. Plants observed in cultivation are characterized by distinctly yellow petioles and beautiful young leaves that emerge flushed reddish bronze and covered with silvery hairs; the coloration of new shoots, however, is variable and some specimens produce only plain green shoots (Grimshaw & Bayton 2009).
The earliest records of this species in Western cultivation are from the famed SICH expeditions to China, joint ventures between Kew, Quarryhill Botanic Garden (now Sonoma Botanical Garden, California), and Howick Arboretum (UK) (Kirkham 2013). The earliest accession is SICH 270, from 1988, and a plant from this seed grows at Kew’s Wakehurst Place, having reached 8 m × 15 cm dbh in 2015 (The Tree Register 2022). Further introductions followed in 1992, under collection numbers SICH 1046 and 1142. Plants from these accessions are growing at all three institutions that sponsored the expeditions. At Sonoma Botanical Garden, a tree from SICH 1142 had reached 5 m in height by 2004, branching from near the base to form a dense mass of foliage (Grimshaw & Bayton 2009). At Kew, a single-stemmed tree from SICH 1046 measured 8 m × 26 cm at 0.5 m in 2021 (The Tree Register 2022). At Howick, a multi-stemmed tree from SICH 1046 reached 8 m × 22 cm dbh at 1 m, with a 5-m canopy spread, while one from SICH 1142 was 7 m × 16 cm with a 6-m canopy spread (R. Jamieson pers. comm. 2021). At Sir Harold Hillier Gardens, a tree form SICH 1146 was 12.4 m × 26 cm at 0.6 m with a canopy spread of 8.4 m, making it the UK and Ireland champion (The Tree Register 2022); two other plants there, from seed collected by John Rippin in Yunan in 1999 (Rippin 198), measured 5.8 m × 14.1 cm dbh and 6.2 m by 6.1 cm dbh (B. Clarke pers. comm. 2021). The species has also done well at Chevithorne Barton, where trees from several accessions have prospered, despite one having blown over in a storm; the largest, planted about 2003, had reached 11 m in 2021 (J. MacEwen pers. comm.). Other gardens in the UK holding this species include Tregrehan – from Yunnan, planted 2000, 6 m in 2020 (T. Hudson pers. comm.), Royal Botanic Garden Edinburgh – from Yunnan, accessioned 2004 (Royal Botanic Garden Edinburgh 2022), and Buckingham Palace – two trees, the larger measuring 8 × 14 cm in 2020 (M. Lane pers. comm.).
Several specialist European collections grow Q. schottkyana: Arboretum de la Bergerette, Arboretum de Passadou, and Arboretum des Pouyouleix in central France; Iturraran Botanical Garden in northeastern Spain, and Trompenburg Gardens in the Netherlands. Most accessions are from wild-sourced seed.
In North America, aside from the plants at Sonoma Botanical Garden, there are a dozen trees at UBC Botanical Garden in Vancouver, ranging in size between 1 and 2 m, wild-sourced from Yunnan – the same accession as that growing in Arboretum de la Bergerette (University of British Columbia 2022; D. Justice pers. comm. 2021).
The species is grown at Kunming Botanical Garden (S. Weibang pers. comm. 2021).
It is not yet widely grown in collections in Australia and New Zealand: the only record is at Geoff Bogle’s arboretum in Hoddles Creek outside Melbourne, Victoria (D. Teese pers. comm. 2021).
The species has proved comfortably hardy in temperate zone cultivation, and has been proposed, together with Q. myrsinifolia and Q. glauca, as an appropriate choice of rootstock for grafting Section Cyclobalanopsis oaks (Humphrey 2020).
The local name in Chinese can be translated as ‘Yunnan evergreen oak’. The species was first described in 1912 by Ernst Max Schottky (1888–1915) as Cyclobalanopsis glaucoides, where glaucoides means ‘resembling glauca’, as he judged it was closely related to C. glauca (Q. glauca). However, this caused a nomenclatural short circuit if Cyclobalanopsis is subsumed in Quercus, (as Koidzumi did in 1916), because Q. glaucoides had already been taken by Martens & Galeotti in 1843, when they described a Mexican species that they found showed an affinity to Q. glaucescens Bonpl. The issue was resolved in late 1916, when in Sargent’s Plantae wilsoniae the Chinese species was renamed as Q. schottkyana Rehder & E.H. Wilson, honouring the botanist who first described it.