Malus transitoria (Batal.) C.K. Schneid.

As usually seen in gardens, this is a lovely wide-spreading, often umbrella-shaped tree, ideal as a lawn specimen for large gardens. White flowers from pink buds are followed by quantities of pea-sized, rich yellow fruits hanging on long pedicels (Edwards & Marshall 2019). However, there is real uncertainty around the identity of many cultivated specimens.

Malus transitoria has much in common with M. toringo and M. bhutanica in general appearance. Following Flora of China (Gu et al. 2003), it is distinguished by both leaf surfaces, as well as the pedicel at flowering time, being tomentose.

Even in his Latin description, from herbarium specimens collected in Gansu, Batalin (1892) reaches for the analogy of small peas when writing about the fruits, but he leaves no clue as to the relevance of the specific epithet, presumably from the Latin transitorius (either ‘having a way through’ or ‘short-lived’). Other poorly known, probably related taxa have since been described, and both diploids and triploids have been recorded. M. transitoria var. glabrescens T. T. Yu & T. C. Ku, from high altitude in eastern Tibet, has a glabrous underside to the leaf, and only sparsely hairy pedicels. M. transitoria var. centralasiatica (Vassilczenko) T. T. Yu, from high altitude in Gansu, Qinghai, and Shaanxi has more elongated fruits. The obscure M. setok Vassilczenko ‘might be an allied species or an ecotype of M. transitoria’ (Gu et al. 2003). Poorly understood variation of this sort makes the identification of cultivated material especially difficult, even without the question of whether sexual, outcrossing species have hybridized early in their cultivation history.

M. transitoria was introduced through seed sent to the Arnold Arboretum by the English plant collector William Purdom in 1911. Purdom, working in western Gansu, records that it was from ‘Tibetan country’ south west of Choni, ‘brought in by Tibetans’ (Sargent 1916). It seems that while the species was grown at the Arnold for many years, it is no longer there (Arnold Arboretum 2020).

Owen Johnson in The Tree Register (2020) wisely casts an aura of doubt around the identity of many British specimens, and highlights a clone probably distributed by the Hillier Nurseries as looking like M. toringo. John Grimshaw (pers. comm. 2020) compared specimens in flower at the Yorkshire Arboretum, one obtained from Hilliers in 1981, the other raised by Keith Rushforth from a Chinese commercial list of Gansu and Hunan seed, and believed by Rushforth to represent M. transitoria from Gansu. The Hillier plant looked ‘very like toringo’, matching it precisely in pedicel characters and in the size and narrow shape of the hypanthium; the flower of the ostensible Gansu plant looked ‘shorter necked’, with a very different hypanthium shape. The underside of the leaf was hairy only on the major veins and midrib in the Hillier plant; the Gansu tree was much more widely hairy as would be expected in M. transitoria. We cannot know for sure whether at some stage a cultivated stock has become mislabelled, or whether even a single round of seed-raising in cultivation has led to a hybrid – perhaps with M. toringo, a diploid sexual species – supplanting the species in general cultivation. Either way, it behoves us to approach trees in this group with open eyes and minds.

Other stocks exist: several specimens from a 1991 Sichuan collection (SICH 709) grow on the Chinese Hillside at RBG Edinburgh (Royal Botanic Garden Edinburgh 2020). Apart from the cultivar ‘Schmidtcutleaf’ (see ‘Cultivars S’), conventionally attributed to this species, M. transitoria seems to be almost unknown in North American cultivation. The drought tolerance and cold hardiness of genuine material (Gu et al. 2003) might make it a good prospect for the central United States.

Along with ‘Schmidtcutleaf’, two British cultivars (‘R.J. Fulcher’ and ‘Thornhayes Tansy’ – see ‘Cultivars R’ and ‘Cultivars T-Z’) are often placed here. While all show some characteristics of M. transitoria, ‘R.J. Fulcher’ is undoubtedly a hybrid, while ‘Thornhayes Tansy’ was raised from seed in the same fruit as both ‘R.J. Fulcher’ and another clear hybrid (K. Croucher, pers. comm. 2020). It would be unwise to claim any of these as unhybridized M. transitoria.