Iljinskaea Al-Shehbaz, Özüdoğru & D.A. German, 2021

Al-Shehbaz, Ihsan A., Özüdoğru, Bariş & German, Dmitry A., 2021, Iljinskaea (Brassicaceae), a new genus based on Conringia planisiliqua, Phytotaxa 500 (2), pp. 142-146 : 143-144

Iljinskaea Al-Shehbaz, Özüdoğru & D.A. German , gen. nov.

Diagnosis:— Iljinskaea is distinguished from Conringia by having strongly latiseptate (vs. 4- or 8-angled, terete, or terete-latiseptate) fruit, nearly veinless (vs. prominently to obscurely 1- or 3-veined) valves, presence (vs. absence) of median nectaries, purple- to brownishveined (vs. yellowish-veined) petals, and subconduplicate (vs. incumbent) cotyledons.

Type:— Iljinskaea planisiliqua (Fisch. & C.A. Mey.)Al-Shehbaz, Özüdoğru & D.A. German , comb. nov. Basionym: Conringia planisiliqua Fisch. & C.A. Mey. , Index Sem. Hort. Petrop. 3: 32. no. 564. 1837.— Fig. 1 .

Description: —Herbs annual, glaucous. Trichomes papillate, mostly on pedicels. Multicellular glands absent. Stems erect, simple or branched above, leafy. Basal leaves petiolate, not rosulate, simple, entire, withered early; cauline leaves sessile, entire, deeply cordate-amplexicaul at base. Racemes many flowered, ebracteate, elongated considerably in fruit; rachis straight; fruiting pedicels erect-ascending, subappressed, minutely papillate or rarely subglabrous, persistent. Sepals narrowly oblong, free, deciduous, erect, equal, base of lateral pair not saccate. Petals white or creamy white, with dark purple or brown veins extending to apex, erect at base, with flaring blade, longer than sepals; blade oblong-oblanceolate, apex obtuse; claw subequaling sepals. Stamens 6, slightly exserted, erect, tetradynamous; filaments wingless, unappendaged, free; anthers oblong, apex obtuse. Nectar glands 4, distinct, extrastaminal; median pair smaller, subconical, 1 each between bases of filament pair; lateral glands slightly 2-lobed. Ovules 26−38 per ovary; placentation parietal. Fruit dehiscent siliques, linear, latiseptate, straight or curved, not inflated, unsegmented; valves thin, obscurely veined, glabrous, strongly torulose, wingless, unappendaged; gynophore obsolete; replum rounded, visible; septum complete, membranous, veinless; style 0.5−1.2(−2) mm long, tapering to apex, persistent; stigma capitate, entire or slightly 2-lobed. Seeds uniseriate, wingless, oblong, plump; seed coat smooth; cotyledons subconduplicate.

Distribution: — Afghanistan, Armenia, Azerbaijan, Bulgaria, China, Georgia, Greece, India, Iran, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, Russia, Tajikistan, Turkey, Turkmenistan, Uzbekistan.

Etymology: — Iljinskaea (pronounced as Ilyinskaea) is named in honor of Soviet and Ukrainian botanist Antonina Pylypivna Iljinska [Antonina Philippovna Ilyinskaya] (1949–) in recognition of her research mainly on the tribe Alysseae , but also on the other Brassicaceae , including the genus Conringia in which she ( Iljinska 2009), based on careful morphological examination, found out the distinctness of C. planisiliqua from the rest of congeners and placed it into a separate section Planisiliqua A.P. Iljinsk. opposed to the type section encompassing the other five Conringia species.

Discussion: —Authors who recognized Conringia as a member of the tribe Brassiceae used the subconduplicate cotyledonary type in what we recognize herein as Iljinskaea planisiliqua as the supporting evidence. However, the cotyledons of this species are closer to the incumbent rather than conduplicate type because only the outer cotyledon is slightly bent on the inner. However, this is a useful distinguishing feature between Conringia and Iljinskaea in addition to the differences listed in the diagnosis above.

Molecular phylogenetic studies ( Nikolov et al. 2019, Walden et al. 2020) strongly support the assignment of Iljinskaea in the tribe Isatideae instead of the Conringieae . It resembles members of the former tribe by having mostly annual, often glabrous and/or glaucous herbs, ebracteate racemes, strongly auriculate to amplexicaul cauline leaves, and lack of floral appendages. The major differences are in the fruit, which is in Iljinskaea dehiscent, linear, many seeded, wingless siliques instead of indehiscent, variously shaped, 1- or rarely 2-seeded, often winged silicles. Iljinskaea also differs by the dark purple- or brownish-veind petals and lack of such venation in the tribe. Their dramatic differences in fruit morphology can be found in several genera, including Tropidocarpum Hooker (1836 : t. 43), a small, New Worldgenus of only four species and the larger (ca. 50 spp.) Eurasian Hesperis Linnaeus (1753: 663) .

The polytomy between Zuvanda , Conringia clavata , and C. persica (see Khosravi et al. 2009) does not necessarily mean that the two genera should be merged as suggested by these authors. A closer morphological comparison of both species with the remaining three species of the Conringia ( C. austriaca ( Jacquin 1775: 45) Sweet (1826: 25) , C. grandiflora , and C. orientalis ), distinguish them by having terete to terete-latiseptate (vs. 4- or 8-angled) fruit, obscurely 1-veined (vs. prominently 1- or 3-veined) valves, and almost smooth (vs. strongly granulate) seeds. This set of characters was used by Iljinska (2009) to split sect. Conringia into to subsect. Clavatae A.P. Iljinsk. that included C. clavata and C. persica and subsect. Conringia for the above three species. Further studies are needed to determine whether or not C. clavata and C. persica ought to be retained in Conringia , united with Zuvanda or segregated to their own genus.

The single species of Iljinskaea is noticeably variable in terms of base chromosome numbers (2n=14, 16, 18; conf. BrassiBase) which makes it a potentially interesting object for karyological studies.

Figures

FIGURE 1. Iljinskaea planisiliqua.A. Part of raceme showing flower and flower bud (star) showing protogyny. B. Fruiting raceme.Scale bar: A = ca. 2 mm; B = ca. 2 cm. Photos by Abdurrahman Sefalı (Bayburt, Turkey).