Lappula tenuis Gurke

Lappula tenuis (Ledeb.) Gürke, Nat. Pflanzenfam. 4 (3 a): 107, 1894 ≡ Echinospermum tenue Ledeb, Fl. Altaic. 1: 201, 1829. ≡ Hackelia tenuis (Ledeb.) Opiz, Oekon. - Techn. Fl. Böhm. 2 (2): 147, 1839. ≡ Myosotis tenuis (Ledeb.) Mörch, Cat. Hort. Hafn.: 64, 1839. ≡ Echinospermum redowskii var. tenue (Ledeb.) Regel, Bull. Soc. Imp. Naturalistes Moscou 41 (I): 84, 1868. ≡ Cynoglossospermum tenue (Ledeb.) Kuntze, Revis. Gen. Pl. 2: 437, 1891. = Lappula monocarpa C. J. Wang, Bull. Bot. Res., Harbin 1 (4): 98, 1981. syn. nov. Type. China, Xinjiang province, Jimunai County, 1130 m a. s. l., 22 August 1974, Xinjiang Exped. 1750 (Holotype: HNWP!). Type. Russia • Altai, Ad fluv. Tscharysch, 1826, Ledebour, Smejow and Politow s. n. (Lecotype by Ovczinnikova (2018), Lectotype: LE 01043915!). Distribution and habitat. Lappula tenuis is distributed in China, Kazakhstan, and Russia (Wang 1981, Ovczinnikova 2009, Chepinoga et al. 2024). This species inhabits grasslands and steppes at altitudes of approximately 1,000 meters above sea level. Phenology. Flowering and fruiting from June to August. Taxonomic notes. Fruits of Lappula typically develop four nutlets; however, an extensive review of herbarium specimens revealed that some individuals, for example, L. caespitosa C. J. Wang (BNU 0033484) and L. microcarpa (Ledeb.) Gürke (BNU 0030476, BNU 0030622, E 00843758), sometimes produce only a single developed nutlet. Due to the infrequent and irregular occurrence of such aberrations, nutlet number is considered an unreliable diagnostic character for species delimitation within the genus. During field surveys, L. tenuis was occasionally found growing sympatrically with L. consanguinea (Fisch. & C. A. Mey.) Gürke and L. anocarpa C. J. Wang. Although these three species share similar vegetative morphology and ovoid nutlet shape, they can be reliably distinguished by the arrangement of glochids: L. tenuis has nutlets with a single row of marginal glochids, whereas L. consanguinea and L. anocarpa bear two or three rows. Ovczinnikova (2005) circumscribed ser. Lappula to include only two species with single-rowed marginal glochids: L. tenuis and L. brachycentroides. Popov (1951) recognized the morphological similarity between these taxa but distinguished L. brachycentroides by the presence of short or absent glochids along the nutlet margins. However, my examination of L. brachycentroides specimens revealed that nutlets on the same individual can exhibit either smooth margins or distinct glochids, with the latter morphology being consistent with that of L. tenuis. Fruit heteromorphism is well documented in the genus Lappula, including variation in glochid presence (glochids or wings, long-glochids, short-glochids, or glochidless) and wing morphology (broad- or narrow-winged). These observations suggest that L. brachycentroides may simply represent a fruit-dimorphic form of L. tenuis. However, as no newly collected material of L. brachycentroides was obtained in this study, the taxonomic status of this species requires further investigation. Additional specimens examined. China. Xinjiang: • Altai, Xinjiang Exped. 10669 (PE 01361016); • Jimunai County, D. H. Liu BNU 2019 XJ 214 (BNU); • Qinghe County, D. H. Liu BNU 2019 XJ 182 (BNU). Kazakhstan. • Akmola region, Lashchinsky N. N. s. n. (NSK 0009103); • East Kazakhstan, Kotukhov A. Yu. s. n. (NSK 0008186); • Zharminsky district, Korolyuk A. Yu. 132 (NSK 0005792); • Kokpekti district, Popov N. V. 1 (NSK 0005797); Russia. • Altai region, Usyk N. A. s. n. (ALTB 1100059605, ALTB 1100060899); • Kemerovo region, Strelnikova T. O. and Manakov Y. A. KEM 18465 (KUZ 026052); • Kosh-Agachsky district, Korolyuk A. Yu. 121 (NSK 0005798); • Ongudaysky district, Maslova O. M. and Khrustaleva I. A. s. n. (NSK 0005819); • Orenburg region, Lashchinsky N. N. L 15-174 (NSK 0009078).