32. Allium tuberosum Rottler ex Sprengel, Syst. Veg. 2: 38. 1825.
Allium argyi H. Léveillé; A. chinense Maximowicz (1859), not G. Don (1827); A. clarkei J. D. Hooker; A. roxburghii Kunth; A. sulvia Buchanan-Hamilton ex D. Don; A. tuberosum Roxburgh (1832); A. uliginosum G. Don (1827), not Ledebour (1830); A. yesoense Nakai.
Bulbs clustered, cylindric; tunic dull yellow to yellowish brown, reticulate to subreticulate. Leaves linear, shorter than scape, 1.5--8 mm wide, flat, solid, margin smooth. Scape 25--60 cm, terete, usually 2-angled, covered with leaf sheaths only at base. Spathe 2- or 3-valved, persistent. Umbel hemispheric to subglobose, laxly many flowered. Pedicels subequal, 2--4 × as long as perianth, bracteolate and several covered with a common bract at base. Perianth white; segments usually with green or yellowish green midvein; outer ones oblong-ovate to oblong-lanceolate, 4--7(--8) × 1.8--3 mm; inner ones oblong-obovate, 4--7(--8) × 2.1--3.5 mm. Filaments narrowly triangular, equal, 2/3--4/5 as long as perianth segments, connate at base and adnate to perianth segments; inner ones slightly wider than outer at base. Ovary obconical-globose, minutely tuberculate, without concave nectaries at base. Fl. and fr. Jul--Sep. 2 n = 16*, 24*, 32*.
Among shrubs, also widely cultivated as a vegetable; 1000--1100 m. Native in SW Shanxi (Yongji Xian); naturalized S China [tropical Asia].
Allium tuberosum is generally regarded as a cultivated species with a tetraploid chromosome number (2 n = 32), although a wild population was recently discovered in Shanxi Province with a diploid number (2 n = 16; Yang et al., Acta Phytotax. Sin. 36: 36--46. 1998). This species has leaves solid and perianth segments usually with a green or yellowish green midvein, whereas its close wild relative, A. ramosum, differs in having leaves fistulose and perianth segments with a pale red midvein. One of us (Xu) agrees with Stearn (Herbertia 11: 238. 1946) that the name A. tataricum Linnaeus f. (Suppl. Pl. 196. 1782) should be regarded as a synonym of A. ramosum. On the other hand, Kamelin regards A. tataricum as a synonym of A. tuberosum over which name it would have priority. He bases his opinion on two specimens (LE), labeled as A. tataricum and made from plants cultivated during the 1790s in the St. Petersburg Botanical Garden, and on his belief that only A. tuberosum never A. ramosum, has been cultivated. However, Kamelin has observed that these two specimens have fistulose leaves, which suggests that they are A. ramosum, unless this character is not diagnostic for the two species. Xu has not seen the specimens but notes that they could be cultivated A. ramosum because, as noted by Stearn (loc. cit.: 229), A. ramosum was already in cultivation in Europe by 1750. Therefore, A. tataricum is here treated as a synonym of A. ramosum, based on Xu’s opinion. The nomenclature of the two species remains unstable because, although the type of A. tuberosum (B) supports the current application of that name, no type has yet been designated for either A. ramosum or A. tataricum. Further studies are required in order to resolve the classification.