The World of Apples

Wild apples

Malus doumeri (Bois) A.Chev.

Description

Malus doumeri is a tree up to 15 m tall. Its leaves are narrowly elliptic-ovate or obovate-lanceolate, 9–15 cm long, white-felted on both sides when young and later hairless, with irregular teeth. The flowers are 2.5–3 cm across with yellowish-white petals. The fruit is yellowish red, round and 2.5–5.5 cm across, drawn out at the top into a short tube 5–8 mm long, and keeps its sepals. In China it flowers in May and fruits in August and September1. The flesh of the fruit contains stone cells, and trees in cultivation have red-flushed young leaves and flowers like those of a hawthorn2.

Range and habitat

It is the most southerly of the apples, an upland tree that ranges from south-eastern China and Taiwan south to southern Vietnam, well into the tropics2. It grows in forest at 1,000–2,000 m in the Chinese provinces of Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Yunnan and Zhejiang, in Taiwan, and in Laos and Vietnam1; the IUCN Red List adds Anhui3. The IUCN Red List assessed it in 2014 as Data Deficient3.

Uses and history

Its fruit is edible1: in Guangdong the wild fruit is eaten fresh and made into drinks, and across its range the tree is grown as a rootstock for apples2, particularly in subtropical regions1. Bois described it as a Pyrus, because of the stone cells in its fruit, from a tree growing at 2,000 m on Lang Biang in central Vietnam, and named it after Paul Doumer, Governor-General of French Indochina2.

Some forms are remarkably hardy: trees raised from seed collected at 2,055 m in Taiwan in 2006 have survived −18 °C undamaged in the Vosges, in France2. The United States apple genebank at Geneva, New York, keeps its trees of the species in a greenhouse because they are sensitive to cold6.

Relationship to the cultivated apple

Chloroplast DNA marks it as particularly distinct genetically, yet in 2015 the United States genebank held a single tree of it6. In 2021 Trees and Shrubs Online reported that material from Vietnam was being sought for its potential in breeding apples for warm climates2.

Its flowers resemble those of Docynia, but it has two ovules in each compartment of the ovary, as other apples do, which is why the Flora of China keeps it in Malus1. A 2023 study confirmed from nuclear and plastid DNA that it is the closest relative of the Docynia species, which share with it several features, among them stone cells scattered through the flesh and deeply lobed juvenile leaves; the study moved Docynia into Malus5.

Where the sources disagree

  • Its place in the genus. In 2021 Trees and Shrubs Online found its place in Malus “not at all clear”, noted that a few sources treat it as Docynia doumeri, and judged that too few molecular studies had included it to draw any conclusion2. The 2023 study cites several earlier plastid and nuclear studies that placed it next to Docynia5. It has also been named Macromeles doumeri4.
  • One species or two. The Flora of China keeps Malus leiocalyca, with a hairless flower cup and flower stalks, as a separate species8. The 2022 revision found the differences continuous and treats it as a synonym, while noting that molecular evidence is still needed7; Plants of the World Online also treats it as a synonym4.
  • Date of the first name. Trees and Shrubs Online dates Bois’s description to 19042; the Flora of China gives 1940, although it dates Chevalier’s transfer of the name to Malus to 19201.

Sources

  1. Malus doumeri, Flora of China vol. 9, Gu Cuizhi and Stephen A. Spongberg, Flora of China, eFloras.org, 2003. Supports: the description (trees to 15 m, leaves narrowly elliptic-ovate or obovate-lanceolate, 9–15 cm, white-tomentose when young, irregularly serrate, flowers 2.5–3 cm, petals yellowish white, pome yellowish red, globose, 2.5–5.5 cm, the top of the hypanthium tubular, 5–8 mm, sepals persistent, flowering May and fruiting August–September); forests at 1,000–2,000 m in Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Taiwan, Yunnan and Zhejiang, and Laos and Vietnam; used as stock for grafting apples in subtropical regions; fruit edible; flowers similar to Docynia, but two ovules per locule, so kept in Malus; Malus doumeri published by Chevalier in 1920, and its basionym Pyrus doumeri Bois cited as published in 1940.
  2. Malus doumeri, Julian Sutton and Nick Dunn, Trees and Shrubs Online (International Dendrology Society), 2021. Supports: "the most southerly occurring member of the genus", an upland tree from south-eastern China and Taiwan to southern Vietnam, well into the tropics; hardy forms in cultivation with red-flushed young leaves and hawthorn-like flowers; fruit flesh with stone cells; described by Bois (1904) from a tree at 2,000 m on Lang Biang, central Vietnam; the epithet commemorating Paul Doumer, Governor-General of French Indochina; cultivated across its native range as a rootstock for apples; wild fruit eaten fresh and used for drinks in Guangdong; first named as a Pyrus because of the stone cells; a few sources treating it as Docynia doumeri, and too few molecular studies for any inference; trees from seed collected at 2,055 m in Taiwan in 2006 surviving −18 °C undamaged in the Vosges; Vietnamese material sought for breeding apples for warm climates; M. leiocalyca sometimes treated as distinct.
  3. Malus doumeri, The IUCN Red List of Threatened Species 2016: e.T61854418A61854658, L. Rhodes and N. Maxted, 2016. Supports: Data Deficient, assessed 1 June 2014; native to China (Anhui, Guangdong, Guangxi, Guizhou, Hunan, Jiangxi, Yunnan, Zhejiang), Laos, Taiwan and Vietnam.
  4. Malus doumeri (Bois) A.Chev., Plants of the World Online, Royal Botanic Gardens, Kew. Supports: accepted name and authority, published 1920; native range "S. China to Indo-China, Taiwan"; Docynia doumeri, Malus melliana, Malus leiocalyca, Malus formosana, Malus laosensis and Macromeles doumeri among the synonyms.
  5. Malus includes Docynia (Maleae, Rosaceae): evidence from phylogenomics and morphology, Guang-Ning Liu and others, PhytoKeys 229: 47–60, 2023. Supports: the close relationship of Docynia and M. doumeri (section Docyniopsis) found in earlier plastid and nuclear studies and confirmed in the authors' nuclear and plastid trees; shared characters (cone-shaped free part of the ovary, fully joined carpels, incurved persistent calyx, stone cells scattered through the flesh, deeply lobed juvenile leaves, similar flavonoid chemistry); Docynia merged into Malus.
  6. The vulnerability of US apple (Malus) genetic resources, Gayle M. Volk and others, Genetic Resources and Crop Evolution 62: 765–794; USDA GRIN, 2015. Supports: accessions of M. doumeri kept in the greenhouse at Geneva, New York, because of chilling sensitivity; M. doumeri identified by chloroplast data as particularly distinctive genetically, and represented by one tree in the US National Plant Germplasm System.
  7. A revision of the genus Malus Mill. (Rosaceae), Jing-chao Li, Jian-quan Liu and Xin-fen Gao, European Journal of Taxonomy 853: 1–127, 2022. Supports: M. doumeri accepted; measurements of specimens of M. doumeri, M. melliana and M. leiocalyca showing continuous variation, so M. leiocalyca treated as a synonym, pending molecular evidence.
  8. Malus leiocalyca, Flora of China vol. 9, Gu Cuizhi and Stephen A. Spongberg, Flora of China, eFloras.org, 2003. Supports: M. leiocalyca treated as a separate species with a glabrous hypanthium and pedicels, in mixed mountain forests and by streams at 700–2,400 m in south-eastern China.