21. Malus ioensis (Alph.Wood) Britton Figs 49–50 An Illustrated Flora of the Northern United States, Canada and the British possessions Vol. 2: 235, fig. 1980 (Britton & Brown 1897). Pyrus coronaria β ioensis Alph.Wood, A Class-book of Botany (Ed. 1861): 333 (Wood 1861). – Pyrus ioensis (Alph.Wood) J.H.Carruth, Transactions of the Kansas Academy of Science 5: 48 (Carruth 1877). – Pyrus ioensis (Alph.Wood) L.H.Bailey, American Garden 12 (8): 473 (Bailey 1891), nom. Carruth 1877. – Malus coronaria var. ioensis (Alph.Wood) C.K.Schneid., Illustriertes Handbuch der Laubholzkunde Vol. 1: 724 (Schneider 1906b). – Malus coronaria subsp. ioensis (Alph.Wood) Likhonos, Trudy po prikladnoi botanike genetike i selektsii 52 (3): 24 (Likhonos 1974). – Type: USA • Missouri, Daviess, near Pattonsburg, thickets, limestone uplands; 14 Jun. 1924; E.J. Palmer 25466; neotype: S, designated by Langenfeld 1991: 153. Malus ioensis var. bushii Rehder, Trees & Shrubs Vol. 2 (4): 232 (Rehder 1913b). – Pyrus ioensis var. bushii (Rehder) L.H.Bailey, Rhodora 18: 154 (Bailey 1916a). – Type: USA • Missouri, Wayne County, Williamsville; 24 Apr. 1912; fl; B.F. Bush 6634; lectotype: A [A00026607]!, here designated; isoletotype: A [A00026608]!, GH [GH00026609]!, NY [NY01163652]!, US [US00097444, US00097445]! Malus ioensis var. creniserrata Rehder, Trees & Shrubs Vol. 2 (4): 231 (Rehder 1913b). – Pyrus ioensis var. creniserrata (Rehder) L.H.Bailey, Rhodora 18: 154 (Bailey 1916a). – Type : USA • Louisiana, Rapides, County, Parish, Pineville; 3 Apr. 1885; fl; C.S. Sargent s.n.; lectotype: A [A00026605]!, here designated; isolectotype: A [A00026606]!, NY [NY01163668]! Malus ioensis var. palmeri Rehder, Trees & Shrubs Vol. 2 (3): 142 (Rehder 1911b). – Pyrus ioensis var. palmeri (Sarg.) L.H.Bailey, Rhodora 18: 154 (Bailey 1916a). – Type : USA • Missouri, Jasper, Webb City, woods; 28 Apr. 1909; fl; E.J. Palmer 1795; lectotype: A [A00026610]!, here designated; isolectotype: A [A00026611, A00026612]!, MO [MO-2217901, MO-2217902]!, NY [NY01163653]! Malus ioensis var. spinosa Rehder, Trees & Shrubs Vol. 2 (4): 231 (Rehder 1913b). – Pyrus ioensis var. spinosa (Rehder) L.H.Bailey, Rhodora 18: 154 (Bailey 1916a). – Malus angustifolia var. spinosa (Rehder) C.F.Reed, Phytologia 63 (5): 410 (Reed 1987). – Type: USA • Missouri, Dunklin, Campbell, low woods; 22 Apr. 1912; fl; B.F. Bush 6630; lectotype: A [A00026613]!, here designated; isolectotype: A [A00026614], GH [GH00026615]!, NY [NY1163649]! Malus ioensis var. texana Rehder, Trees & Shrubs Vol. 2 (3): 142–143 (Rehder 1911b). – Pyrus ioensis var. texana (Rehder) L.H.Bailey, Rhodora 18: 154 (Bailey 1916a). – Type: USA • Texas, Kendall County, Boerne; thicks; 25 Mar. 1911; fl; C.S. Sargent s.n.; lectotype: A [A000283735]!, here designated; isolectotype: A [A000283736]! Malus ioensis var. typica Rehder, Mitteilungen der deutschen dendrologischen Gesellschaft 1914: 262 (Rehder 1914), nom. inval. Malus ioensis f. plena Rehder, Mitteilungen der deutschen dendrologischen Gesellschaft 1914: 262 (Rehder 1914), nom. inval. Malus ioensis f. fimbriata A.D.Slavin, American Midland Naturalist 12 (9): 363 (Slavin 1931). Examined specimens UNITED STATES – Illinois • locality unknown; s.d.; st; Anonymous s.n.; A [01861806] • ibid.; st; Anonymous s.n.; A [01861750]. – Indiana: Daviess; s.d.; fl; Anonymous s.n.; GH [01861773] • ibid.; 6 May 1919; fl; Chas. C. Deam No.26, 267; GH. – Iowa • Iowa State College; 24 Jul. 1926; st; A. Haydeu 14143; PE. – Massachusetts • Norfolk; 24 May 1922; fl; N.T. Kidder s.n.; ECON. – Missouri • Wedd; 28 Apr. 1909; fl; E.J. Palmer 1795; A • Williamsville; 24 Apr. 1912; fl; B.F. Bush 6634; GH. – Oklahoma • Vinita; 5 Aug. 1894; st; B.F. Bush 325; A. – Texas • near Boerne; 24 Mar. 1911; fl; C.S. Sargent s.n.; A • ibid.; 7 Oct. 1910; st; S.H. Hastings s.n.; A • Kendall; 27 May 1916; fr; E.J. Palmer 9911; A. – Wisconsin • Richland; 21 Sep. 1988; st; M. Nee 36806; PE. Description Small tree, 6‒8 (10) m high, or shrub, 4‒7 m high. Branches terete, pubescent when young, glabrescent. Leaves petiolate, petiole ca 1.0‒ 3.3 cm long, puberulous. Lamina ca 3.3‒8.3 × 1.9‒4.6 cm, oblong to ovate, base truncate, cuneate or rounded, equilateral, apex acute, rounded or obtuse, margin crenate to serrulate, blade glabrous or puberulous, sometimes lobed. Inflorescence corymbose, with 3‒5 flowers. Pedicel ca 1.7‒2.2 cm long, puberulous. Hypanthium densely puberulous. Sepals triangular, puberulous, persistent. Petals ca 1.1‒1.5 × 0.7‒1.1 cm, white, pink or premium pink, obovate to oblong. Stamens ca 20, unequal. Styles 5, as long as stamens, pubescent at base. Pome ca 2.0‒3.0 cm in diameter, subglobose, yellow. Carpopodium ca 2.1‒2.5 cm long, puberulous. Phenology Flowers from April to May. Mature fruits from September to October. Habitat Terrestrial, seasonally green, growing in forests and shrubs in open areas of valleys; 100‒300 m a.s.l. Distribution United States (Fig. 49). Chromosome numbers 2n = 34, 68.

Published as part of Li, Jing-chao, Liu, Jian-quan & Gao, Xin-fen, 2022, A revision of the genus Malus Mill. (Rosaceae), pp. 1-127 in European Journal of Taxonomy 853 on pages 74-76, DOI: 10.5852/ejt.2022.853.2019, http://zenodo.org/record/7501371