12. Malus transitoria (Batalin) C.K.Schneid.

Figs 31–32

Illustriertes Handbuch der Laubholzkunde Vol. 1: 726 (Schneider 1906b).

Pyrus transitoria Batalin, Trudy imperatorskago S.-Peterburgskago botanicheskago Sada 13 (1): 95‒96 (Batalin 1893). – Sinomalus transitoria (Batalin) Koidz., Acta Phytotaxonomica et Geobotanica 3 (4): 196 (Koidzumi 1934b).

– Type: CHINA • Kansa (Gansu), the eastern ridge of the Sodis-kruxum; 16 (28) May 1873; fl; 20 Aug. (1 Sep.) 1873; fr; Przewalsky 55; lectotype: LE [LE01015142]!, K [K000758424]!, P [P03240528]!, designated by Batalin 1893: 95‒96 and Langenfeld 1991: 138–139.

Malus centralasiatica Vassilcz., Botanicheskie Materialy Gerbariya botanicheskago instituta imeni V.L. Komarova Akademii nauk SSSR 19: 202 (Vassilczenko 1959). – Malus transitoria var. centralasiatica (Vass.) T.T.Yu, Flora Reipublicae Popularis Sinicae Vol. 36: 394 (Yu 1974), syn. nov.

– Type: CHINA • Gansu, Xining, La Che Tze Shan Mountains; alt. 3900 m (actually alt. 2200‒2850 m); 3 Aug. 1923; fr; R.C. Ching 724; holotype: LE; isotype: A [A00368974]!, PE [PE00953983]!, SYS [SYS00074312] !.

Malus transitoria var. glabrescens T.T.Yu & L.T.Lu, Acta Phytotaxonomics Sinica 18 (4): 496 (Yu et al. 1980), syn. nov.

– Type: CHINA • Tibet, Qamdo (Changdu); alt. 3550 m; 26 Apr. 1976; Qing-Zang Exped. Veg. Group 10023; holotype: PE [PE00964002] !

Malus transitoria var. calycomeles Cheng, Zeng & Jin, Journal of Southwest Agricultural University 17 (1): 1 (Cheng et al. 1995), syn. nov.

– Type: CHINA • Sichuan, Ruoergai; alt. 2500 m; M.H. Cheng et al. 91‒87; lectotype: HWA, here designated .

Examined specimens

CHINA – Beijing • Haidian; 13 Aug. 1962; fr; Renguo 12; PE . – Gansu • Diebuxian; 30 Sep. 2005; fr; A. Aiello et al. 080; PE • Lanzhou; 21 Sep. 2003; fr; C.M. Tan et al. Lanzhou005; JJF, SZG • Ningxian; 15 May 2014; fl; X.Y. Xu 20140515047; QYTC • ibid.; 15 May 2014; fl; W. Hui 20140515052; QYTC • Heshui; 28 Jun. 1954; fr; Yellow River Investigation Team 113; PE • Jinchi; 27 Jul. 1990; fr; L.P. Liu 00019; QYTC • Gannan; 1 Sep. 2012; st; S.Q. Guo & P. Du LiuJQ-2012-GN-185; KUN • ibid.; 21 Sep. 1957; fr; Z.L. Yan & P. Zhang 1063; PE • ibid.; 29 May 1956; st; Yellow River Investigation Team 4152; PE • ibid.; 1 Sep. 1960; fr; Qinggan Team 3400; PE • T’ao River basin; Jun. 1925; fl; J.F. Rock 12188; PE . – Inner Mongolia • Alashan; 23 Jun. 1962; fl; He group 85; NAS • ibid.; 2 Aug. 2011; fr; Beijing Normal University Ningxia Team HL114; BNU • Helanshan; Sep. 1956; fl; W.Z. Fang s.n.; NAS • ibid.; 30 Aug. 2008; fr; Y.Z. Zhao & S.Q. Zhou 2423; HIMC • ibid.; 23 Jun. 1962; fl; Biology department senior year 85; PE, HIMC . – Ningxia • Helanshan; 18 Jun. 1973; fr; Ningxia Yaojiansuo 73-0167; PE . – Qinghai • Xunhua; 27 Jun. 1981; st; B.Z. Guo 25400; HNWP • Yushu; 12 Aug. 1981; fr; Z.K. Wei 22383; HNWP • Hualong; 6 Jun. 2004; fl; Y.H. Wu 28576; HNWP • Huzhu; 10 Sep. 1980; fr; R.F. Huang & Y.C. Yang 1747; HNWP • Tongren; 28 Jul. 1970; fr; L.H. Zhou & H.H. Zhang 1295; HNWP . – Shaanxi • Jingbian; 23 Jun. 1952; fr; J.M. Liu 11636; PE • Yanan; 19 Jun. 1993; fl; L.R. Xu 1670; PE • Shanbei; 4 Sep. 1953; fr; Shanbei Team 10652; CDBI • Huashan; 14 Sep. 1978; fr; Z.Y. Zhang 18227; IBSC . – Sichuan • Kangding; 14 Jun. 1980; fl; Z.Y. Chen et al. 112699; PE • Hongyuan; 14 Sep. 1957; fr; X. Li 74662; PE • Daofu; 23 Jul. 1959; fr; S. Jiang et al. 002352; PE • Xikang; 8 Aug. 1951; fr; Y.W. Cui 5198a; PE • Aba; 2 Aug. 1975; fr; Sichuan zhibei Team 10487; CDBI • Dege; 1 Jun. 1977; fr; Sichuan zhibei Team 15073; CDBI . – Tibet • Changdu; 26 Aug. 1973; fr; Tibet Expedition Team 2248; HNWP • ibid.; 26 Sep. 2008; fr; Y.H. Zhang, G.D. Li & X.X. Wang SunH-07ZX-1761; KUN • ibid.; 24 Sep. 2008; fr; C.R. Zaxi, L. Xi & Y.P. Geng ZhongY752; KUN .

Description

Small tree or shrub, 3‒5 m high, rarely 8 m. Branches terete, pubescent when young, glabrescent. Leaves petiolate, petiole ca 0.8‒1.9 cm long, densely lanuginous. Lamina 3.4‒6.8 × 2.3‒3.6 cm, oval to ovate, base rounded, cuneate or cordate, equilateral, apex acuminate or obtuse, margin crenate to serrulate, blade puberulous when young, then abaxially glabrescent, usually 3‒5 divided. Inflorescence umbelliform corymb, with 3‒6 flowers. Pedicel ca 1.7‒2.0 cm long, puberulous. Hypanthium lanuginous. Sepals triangular, densely puberulous, caducous, rarely persistent. Petals ca 0.7‒0.9 × 0.4‒0.6 cm, white, obovate or oblong. Stamens 20‒25, unequal. Styles 3‒5, longer than stamens, glabrous. Pome ca 0.6‒0.8 cm in diameter, subglobose, yellow to red. Carpopodium ca 2.3‒2.8 cm long, puberulous.

Phenology

Flowers from April to May. Mature fruits in September.

Habitat

Terrestrial, seasonally green, growing in forests on slopes or loess hills; 1500‒3900 m a.s.l.

Distribution

China (Inner Mongolia, Ningxia, Qinghai, Shaanxi, Gansu, Sichuan, Yunnan, Tibet) (Fig. 31).

Chromosome numbers

2n = 34, 51.

Note

There are plentiful morphological variations within this species. Varieties that have been defined on the basis of a few characters and locations are unjustified because such unique phenotypic characters have probably been affected by the environment. Therefore, three new synonyms are proposed in this study ( Malus transitoria var. glabrescens, M. transitoria var. calycomeles, and M. transitoria var. centralasiatica).

The vertical vicariance of Malus kansuensis (distribution below 3000 m), M. toringoides (2600‒3050 m) and M. transitoria (above 3000 m) is very remarkable, and there are no obvious reproductive barriers between them.As a consequence, hybrids that show characters of both parents could be found in the contact zones; for example, the specimens from Maerkang (Sichuan, China) exhibit continuous morphological variation between M. transitoria and M. toringoides .