Parrya tojibaevii D.A. German & Madaminov, 2024

German, Dmitry A. & Madaminov, Farrukhbek M., 2024, A new, highly endangered and restricted-range species of Parrya sect. Pseudoclausia, comb. nov. (Brassicaceae) from Western Tian Shan, Uzbekistan, Phytotaxa 633 (2), pp. 145-154 : 146-150

Parrya tojibaevii D.A. German & Madaminov , sp. nov.

Type:— UZBEKISTAN. Tashkent Province, western branches of Chatkal Range, left bank of Chatkal opposite to the natural monument Obirakhmat , ca. 950 m a.s.l., open clayey-gravelly slopes, 41°33’44.334” N, 70°06’21.319” E, 6 May 2023, D. A. German, F. M. Madaminov, G. T. Kurbaniyazova & G. Kh. Bukharov s. n. (holotype: TASH054556 ; isotypes: AA, ALTB, TASH054549 , TASH054555 , also to be distributed elsewhere) .

Biennial herb, rather densely covered throughout (except for petals, stamens, and stigmas) with a mixture of stipitate glands 0.2–0.4(–0.5) mm long and patent simple trichomes (0.5–)1–4(–7) mm long (the latter sometimes rare or absent on upper part of rachis, pedicels and rarely sepals) and therefore hispid; longest (3–7 mm) trichomes restricted to rosette leaves, shortest (mainly to 1 mm) to styles; most of other trichomes range within 1.5–2.5(–3) mm, on average longest in lower half of stems and shortest on sepals, though variation in trichome length on the same organs is observed among and even within individual plants. Leaves of first-year rosettes to 3.5 × 1.7 cm, elliptic to narrowly elliptic in outline, with 4(–5) subacute to obtusate, triangular to lanceolate-triangular, usually entire, sometimes indistinctly and minutely toothed teeth or lobes, less often subentire, predominantly obtusate, gradually narrowed into petiole to 2 cm with somewhat expanded base. Stems (15–)25–40(70) cm tall, stout, single, branched in lower third; branches ascending, often simple, rarely few-branched. Basal leaves narrowly elliptic to broadly lanceolate or lanceolate in outline, cuneate, sessile or shortly (to 1.5 cm) petiolate, to 5 × 1.5 cm, pinnatifid or pinnatipartite, rarely pinnatisect, with 4–6(–7) usually remote, triangular to oblong-lanceolate, entire or rarely weakly denticulate teeth or lobes on each side, with acute or obtusate apex, along with stem ones withering by fruit (sub)maturity. Stem leaves: lowermost similar to basal, others predominantly narrowly ovate to broadly lanceolate, partly lanceolate and (usually on secondary branches) linear-lanceolate, to 4.2 × 1.9 cm, progressively smaller upward, sessile or nearly so, cuneate or narrowed to a petiole-like base, acute, serrate to (uppermost sometimes) remotely denticulate, with (2–)4– 6(–7) pairs of teeth. Racemes ebracteate, (6–)8–30(–36)-flowered, terminating stem and all branches, rather lax and considerably elongating in fruit; rachis straight. Pedicels ascending, flowering slender, 2–4.5 mm; fruiting thickened, 0.8–1.2 mm wide proximally and expanded to ca. 1.5 mm distally, straight or slightly curved upward in lower part, 4–7 mm long. Sepals oblong-linear, gradually narrowing towards apex, erect, deep purple coloured, narrowly (widest at the apex) hyaline-margined, fading turning blackish, (6.5–)7–9(–10.5) × 1.8–3 mm, lateral slightly saccate at base. Petals 10–16 × 1.5–2 mm, indistinctly differentiated into claw and blade; claw 7–11 mm, slightly exceeding sepals, narrowly cuneiform, in proximal and middle part whitish, with indistinct and rather blurred pale green midvein, distally starting turning wine from central part in the lowest point through the transitional zone between the claw and blade and reaching (almost) the whole width by the beginning of blade, with pale yellow margins, sometimes protruding to proximal part of the blade; blade 3–5 mm, narrowly oblong, rounded to subtruncate, not emarginate, in fully open flowers recurved, grooved, usually undulate, wine-coloured (darkest in central part), fading turning black. Stamens slightly tetradynamous, 8–11.5 mm, with narrow filaments slightly gradually expanded towards the base in inner ones; anthers oblong-linear to linear, sagittate, acute, 2.2–3.5 mm in lateral and 3–4 mm in median stamens, respectively. Siliques (3.2–)4–6(–7) cm × 1.8–2.1(–2.3) mm, immature compressed-tetragonal, mature terete or weakly tetragonalterete, straight to very slightly curved upward, ascending, tardily dehiscent; valves with distinct midvein and obscure lateral ones; septum opaque, with slightly translucent, wide midvein throughout the whole length. Ovules/seeds (30–) 40–58 per ovary/fruit; seeds compressed, oblong to broadly oblong-elliptic, brown, 1.8–2.1 × 1.2–1.6 mm, very narrowly margined all round. Styles cylindric, stout, without stigma (1–)2–3(–4) mm long; stigmas narrowly conical, (1.5–)2–2.8(–4) mm, with strongly connivent lobes shortly diverged only in distalmost part. Fig. 1 .

Affinity: —Based on morphological characters, Parrya tojibaevii appears to be most closely related to P. gracillima and P. mollissima (Lipsky) D.A. German & Al-Shehbaz ( Al-Shehbaz & German 2013: 464), both endemics of the Western Tian Shan and belonging to P. sect. Pseudoclausia , with long trichomes (up to 4.5 mm in the prior and up to 6 mm in the latter) on primary rosette leaves. Among the two, P. mollissima is the nearest relative of the new species resembling P. tojibaevii in habit of fruiting plants, character of indumentum, fruit, style and stigma dimensions, ovules/ seeds number and ecology, but considerably differing in bigger (up to 9.5 cm, including petiole up to 2.8 cm), usually lyrate-pinnatisect rosette leaves, white or very pale pink (with deep pink zone of transition to a claw and venation), spreading petals 1.7–2.5 cm × 3–6 mm with obtriangular, apically emarginate blade, pedicels 6–15 mm long, light green (vs. intensive green) colour of leaves and further, less distinct features. With P. gracillima , the new species shares flower size and intensive green colour or stems, leaves and young fruits. Most obvious differences of P. gracillima from P. tojibaevii include light to deep pink, sometimes lighter proximally, turning violet when fading, spreading petals with narrowly obtriangular, truncate or weakly emarginate, sometimes subrounded blade, narrower (1–1.5 mm wide), tetragonal siliques, higher number (60–90) of smaller (1.3–2 × 1–1.3 mm) seeds, shorter (1–1.5 mm long) stigmas and less robust habit. Ecologically, P. gracillima differs in preferring mesic habitats with developed vegetation (vs. xeric and open), although sometimes it occurs under conditions typical of P. tojibaevii . Both P. gracillima and P. mollissima can be distinguished from P. tojibaevii in generally narrower (predominantly narrowly lanceolate to linear-lanceolate) cauline leaves.

Etymology: —Named in honour of Komiljon Sharobitdinovich Tojibaev, Head of the Institute of Botany,Academy of Sciences of Uzbekistan, and Leader of the ongoing project ‘Flora of Uzbekistan’ (since 2016), in recognition of his scientific and organizational contribution to the contemporary inventory, analysis and conservation of the flora of the Western Tian Shan, Uzbekistan and Middle Asia in general.

Distribution and habitat: —The novelty is known thus far from a small area around the place of the confluence of the Chatkal River with the Charvak Reservoir ( Fig. 2 ). It was predominantly collected and observed along ca. 6 km of the left bank of Chatkal/Charvak, i. e. on branches of Chatkal Range. Besides, a single collection was made at the right bank of Chatkal, belonging to Koksu (wrongly indicated as Pskem on the label) Range, just opposite to the southern (upper) end of the above 6-km bank line. Therefore, it should be assigned to the same population which is thus currently the single known one. All collections and observations fall within the narrow altitudinal range of 900–1300 m a.s.l.

It is important to note that the species occurs in the area of intensive human activity which negatively affects its population and may even threaten its existence. First, at least one locality (vicinities of Shungak) is apparently gone since Shungak Village was flooded in 1970 by the construction of the Charvak Reservoir. Second, banks of the reservoir are heavily exploited as tourist/recreation zone with a growing number of hotels, guesthouses, resorts, restaurants, summer camps, beaches, etc. Third, a large new threat is the ongoing construction of the Lower Chatkal hydroelectric power station situated just 2.5 kilometers upstream the habitat of the species. The launch of this power station (planned in 2025) and the development of its infrastructure (roads, power lines, etc.) will inevitably lead to further habitat losses of P. tojibaevii . And finally, intensive livestock grazing also has a negative impact on the species and local vegetation in general.

Although the territory around the Charvak Reservoir belongs to the Ugam-Chatkal National Park (506,941 hectares), a protected area of IUCN category II, in reality an economic growth, energy production and tourism take priority over the biodiversity conservation in this area ( Volis 2022).

Phenology: —Flowering in mid-April to mid-(late) May, fruiting in May to early June.

Ecology: —Occurs on steep, rarely gentle, clayey-gravelly and stony slopes of predominantly east- and northeastfacing exposition ( Fig. 3 ). Also found at the roadside on the same type of substrate. Apparently reveals low competitive ability growing on bare soil with no or very scarce vegetation, but sometimes occurs in xeric open shrublands and grass-forb communities. Alyssum simplex Rudolphi , Crambe orientalis L., Glaucium fimbrilligerum Boiss. , Guenthera persica (Boiss. & Hohen.) D.A. German , Hordeum bulbosum L., Poa bulbosa L., Prunus erythrocarpa (Nevski) Gilli and Scandix stellata Banks & Sol. were found to be the most common accompanying species. The following endemic and threatened plants ( Khassanov 2019) were recorded in the study area around the confluence of the Chatkal River with the Charvak Reservoir: Eremurus lactiflorus O. Fedtsch. ( Asphodelaceae , endemic to Western Tian Shan listed in the Red Data Book of Uzbekistan), Hedysarum drobovii Korotk. ( Fabaceae , extremely rare endemic of the Western Tian Shan and Uzbekistan, listed in the Red Data Book of Uzbekistan), Iris orchioides Carriere ( Iridaceae , endemic to the Western Tian Shan listed in the Red Data Books of Kazakhstan, Kyrgyzstan and Uzbekistan), Parrya tschimganica (Popov ex Botsch. & Vved.) D.A. German & Al-Shehbaz ( Brassicaceae , extremely rare endemic of the Western Tian Shan listed in the Red Data Book of Uzbekistan), Rubia laevissima Tscherneva ( Rubiaceae , endemic to the Western Tian Shan listed in the Red Data Book of Uzbekistan), Salvia korolkowii Regel & Schmalh. ( Lamiaceae , endemic to the Western Tian Shan listed in the IUCN Red List and Red Data Books of Kyrgyzstan and Uzbekistan), Tulipa greigii Regel ( Liliaceae , endemic to the Western Tian Shan listed in the Red Data Books of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan).

Biology: —Appears to be cross-pollinated. Bee flies ( Bombyliidae ) are noticed visiting flowers of Parrya tojibaevii .

Conservation status: — Parrya tojibaevii appears to be a stenoendemic species facing real threat of extinction because of human impact and natural factors. Its extent of occupancy (EOO) and area of occupancy (AOO) are 8 km 2 only. Since the only subpopulation of the species may suffer or go extinct from a single threatening event, the number of localities should be estimated as one. Then, criteria B1 and B2ab(iii,iv) of IUCN (2022) are met for estimating the conservation status of the species as critically endangered (CR). As noted above, the major direct and indirect threats are connected with the residential and commercial development, energy production and natural system modifications. The main natural threats are geological events (mudflows and landslides), as well as climate change.

Additional specimens examined: — UZBEKISTAN: Northern clayey-stony slope (conglomerate talus slopes) in vicinities of Kupryuk-bashi (near Brichmulla ), 900–1000 m, 30 July 1950 [fr. mat., sicc.], I. T. Vassilczenko & V. F. Golubkova 229 ( LE, 3×) ; Syr-Darya Prov., Tashkent Distr., near Brich-Mulla , slope at the left bank of Chatkal [fr. mat., sicc.], 18 June 1921, V. P. Drobov 30 ( TASH054075 , TASH054094 ) ; Western Tian Shan. Valley of Chatkal. Vicinities of Shungak [fl., fr. immat.], 8 May 1962, T. [ A.] Adylov & [ T. I.] Zuckerwanik 67 ( TASH054461 ) ; Western Tian Shan. Pskem Range, lower reaches of Fartob ( Pal’tau ) [fl.], 25 April 1966, T. Adylov 1805 ( TASH054083 , TASH054090 , TASH054091 ) ; Tashkent Province, Bostanlyk District, slope at the left bank of Chatkal on the opposite of natural boundary Obirakhmat near the confluence with Charvak Reservior [fl.], 16 April 2016, A. D. Gaziev s. n. ( TASH053958 ) ; the same locality [defl., fr.], 26 May 2015, A. D. Gaziev s. n. ( TASH053957 ) ; the same locality [fl., fr. immat.], 27 April 2021, F. M. Madaminov 49–62 ( TASH 053991–054004 ) ; the same locality [fl., fr. immat.], 26 April 2022, F. M. Madaminov 105–118 ( TASH 054354–054367 ) ; the same locality [fr.], 8 June 2023, N. Yu. Beshko & al. s. n. ( TASH, ALTB) .

Figures

FIGURE 1. Living plant of Parrya tojibaevii: (A) plant in natural habit; (B) and (C) part of inflorescence and infructescence; (D) firstyear rosettes.

FIGURE 2. Distribution of Parrya tojibaevii and related species within the study area.

FIGURE 3. Habitat of Parrya tojibaevii near the confluence of the Chatkal River with the Charvak Reservoir.