Lepidium obtusum, Basiner, 1844

German, Dmitry A., 2014, Taxonomic remarks on some Asian Lepidium s. l. (Brassicaceae), Phytotaxa 186 (2), pp. 97-105 : 103

4. Lepidium obtusum

Lepidium obtusum Basiner (1844: 203) . Lectotype (designated by German 2011: 52):— UZBEKISTAN. In locis argillososalsis terrae Chivensium leg. d. 9 Sptmbr. 1842 Basiner s.n. (LE!, isolectotypes (3×) LE!).

= L. deserti Pavlov (1952: 86) , syn. nov. Type :— KAZAKHSTAN. Karaganda prov. Vicinities of the lake Balkhash, desert steppe near the bay Sar-Chagan. 29 V 1951. N.V. Pavlov 385 (holotype AA!; isotype MW!).

Lepidium obtusum Basin. belongs to the affinity of L. latifolium Linnaeus (1753: 644) but specifically differs from other members of this group by a combination of leathery non-auriculate leaves, often developed pubescence, very dense, not or very slightly elongated by anthesis terminal racemes forming general subcorymbiform-paniculate inflorescence, short and usually pubescent pedicels, persistent perianth and broadly ovate, cordate at the base and carinate silicles with sessile stigma. Being widely distributed in arid and mountainous regions of Kazakhstan, Middle and Central Asia, it is characterized by considerable range of morphological variation including degree of pubescence (dense to sparse), its localization (e. g., presence or absense of trichomes on stems, leaves, and fruits), leaf shape (ovate or elliptic to linear) and apex form (obtuse to acute), stem branching (from the base or predominantly above), etc. Relatively local race characterized by dense indumentum, ultimately narrow leaves (all linear, not more than 7 mm wide) and stems much branched from the base occurs in central eastern Kazakhstan (vicinities of the lake Balkhash, Betpakdala desert and adjacent part of Kazakh upland). It was described two times at the rank of variety, as L. latifolium var. angustifolium Meyer (1831: 191) (pro parte) and L. latifolium var. linearifolium Trautvetter (1860: 129) and finally as a distinct species, L deserti ( Pavlov 1952) . Despite having very specific habit, it is connected by continuous range of intermediates with other morphological variants of L. obtusum . Fruits of this race have not yet been characterized (conf. Vassiljeva 1961, Vinogradova 1974) because types of both L. deserti and L. latifolium var. linearifolium are represented by plants with buds and first flowers. Original material of L. latifolium var. angustifolium includes three gatherings (two from NW Kazakhstan and one from SE part of Kazakh upland), and one syntype from the region in question bears few fruits which are typical for L. obtusum proving that L. deserti is definitely conspecific with the latter. At the same time, taking into consideration some geographic specificity of the discussed race, it is probably worthy of being treated as a variety of L. obtusum . In this case, Trautvetter’s combination should be taken as a basionym because the early-published L. latifolium var. angustifolium has been typified by a specimen from NW Kazakhstan ( German 2005) morphologically not identical to L. deserti (in particular, it has lanceolate, broadly lanceolate and even narrowly ovate-lanceolate instead of linear leaves and stems branched above).

There was an attempt to clarify the position of L. deserti by Latowski (1982) who tentatively (and correctly) synonymized this name with Trautvetter’s variety. However, he followed Thellung (1906) in treating L. latifolium var. linearifolium as a variety of L. latifolium subsp. latifolium and not subsp. obtusum (Basin.) Thellung (1906: 159 , 162) [≡ L. obtusum ], a viewpoind not supported by the data presented here.

Lepidium obtusum has not yet been recorded from Afghanistan ( Hedge 1968, Podlech 2012, Breckle et al. 2013). The specimens cited below document occurence of the species in the north of the country. Closest localities are known from adjacent Tajikistan almost on the Tajik/Afghan border ( Junussov 1978).

Afghanian specimens studied (all sub nom. L. latifolium L.):— AFGHANISTAN. Prov. Balkh, 15 km NW Balkh, versalzter Graben. 28 August 1976, [S.-W.] Breckle 4682 ( MSB 118907 !); Prov. Takhar: Mughul , 20 km nord-westlich von Taluqan, 740; Lössboden. 15 June 1965, D. Podlech 11380 (M!, MSB 118894!); Prov. Maraz-i Sharif: Balkh (Wazirabad), ca. 36°46’N, 66°50’E, in ruderatis inter ruinas, ca. 400 m. 5 June 1962, K.H. Rechinger 16169 (M!)