Taraxacum compactum Schischkin (1949a: 5)

Kirschner, Jan & Štěpánek, Jan, 2023, A taxonomic revision of Taraxacum sect. Dissecta, a continental steppe group common in Siberia and adjacent regions of Central Asia, Phytotaxa 590 (1), pp. 1921-1935 : 1921-1935

Taraxacum compactum Schischkin (1949a: 5) , see also Schischkin (1949b)

Type:—[ RUSSIA, Respublika Altay] Altai, Usť-Koksu , u dorogi [the Altai, Ust-Koksu, along a road], 15 Jul 1931, B. Shishkin ( LE, no. det. 6095, lectotype, designated here; isotypes: LE!, S!, including achenes) .

A note on the typification:— Schischkin (1949a) clearly indicated the herbarium of the Instute of Botany of the Academy of Sciences of the USSR (LE) as the collection where the type of T. compactum should have been deposited. Tzvelev (when completing and editing the Taraxacum treatment in Schischkin 1964) indicated Tomsk (TK) as the collection with this type. In TK, no type specimen of the name T. compactum was located (I. Gureeva, in litt.). We therefore select the best herbarium specimen of the syntypes preserved at LE, and designate it as the lectotype. It should be added that the lectotype specimen was collected on July 15, 1931, as written on two labels by Schischkin himself. In the published protologue, Schischkin (1949a) gives 12 Aug 1931 in the Russian version, and 12 Jul 1931 in the Latin one. Moreover, one of the isotypes bears a label with a date 15 Jul 1937 [sic!, the year was printed on the label, and we treat 1937 as a mistake].

Taraxacum compactum used to be understood as a member of T. sect. Dissecta ( Tzvelev 1987) , or compared with species belonging or believed to belong to T. sect. Dissecta ( Schischkin 1949b) . A closer examination of the type material shows that T. compactum has the following achene characters:

Achenes light greyish stramineous-brown, 3.6–3.8 × ca. 0.8 mm, body with ± dense short suberect squamules in upper 1/5–1/4, with a gradual transition into a thick conical cone 0.3–0.6 mm long, 0.35–0.4 mm thick at base, 0.25–0.3 mm distally; beak ca. 6 mm long, pappus ± white, ca. 5 mm long.

In addition, outer phyllaries are appressed, ovate to ovate-lanceolate, almost without visible border, or with a narrow membranous border. Leaves are rather late, and it is not advisable to use them in our comparison. All the above characters identify T. compactum as a member of T. sect. Qaisera (Abedin 2007, Kirschner et al. 2020). The achenes of T. compactum are even very close to those of T. qaiseri Abedin in their shape and size.

Taraxacum kuvajevii Tzvelev in Tzvelev & Jurtzev (1984: 196)

Type:— Yakutia, Lenskiy r-n, k-z “Dvigateľ”, melkozlakovo-klevernyy vygon po II poime Leny za rechkoi Mukhtuikai , 0.5 km vyshe okrainy poselka Mukhtuya [Sakha Republic, Lensky District, Lensk, ca. 60° 43’ N, 114° 54’ E], 25 Jul 1953, V. Kuvaev & A. Petrov 58/11 ( LE, no. det. 6046, holotype) .

This species, described from the southwesternmost part of Sakha Republic (Yakutia), was taken into consideration because of its small, red-brown achenes with a short cone. It was referred to T. sect. Erythrosperma by its author ( Tzvelev 1984). However, it possesses a feature that excludes it from the proximity of both T. sect. Erythrosperma and T. sect. Dissecta : the enormously long robust acuminate horns on the outer phyllaries. It most probably represents a marginal member of T. sect. Borealia .

Taraxacum pawlodarskum Doll (1973: 497)

Type :—[ KAZAKHSTAN] Kazakhskaya SSR. Pavlodarskaya oblasť , r-n. Urlyutyubinskiy, v 1 km k vostoku ot Zhelezinki, sornyaki na poseve prosa, 29 Jun 1955, N. N. Tzvelev 715 ( LE, no. det. 6503, holotype) .

The type specimen was collected rather late and is not very well developed. However, there is a gathering (and a cultivated material) of the same taxon from SE. Kazakhstan, and we were able to study T. pawlodarskum in detail. The holotype differs from well developed plants in the leaf shape, erect outer phyllaries and less pronounced achene spinulosity. The very densely, distinctly, wholly spinulose achene body and most of the other features show that T. pawlodarskum is a marginal member of T. sect. Macrocornuta van Soest (1960: 304) , see also Kirschner & Štěpánek (2008).

Taraxacum ustamenum Doll (1973: 498)

Type:— Kazakhskaya A.S.S.R., Usťkamenogorsk, yuzhnyy schchebnistyy polynno-tipchakovyy sklon, 28 May 1931, B. Schischkin, E. Schteinberg & T. Sumnevich s.n. ( LE, no. det. 7948, holotype)

The material available consists of a single herbarium specimen with plants collected just after anthesis. There are a few florets to be examined, and only on one or two capitula, it is possible to study outer phyllaries. We give a brief description compiled on the basis of a detailed examination of the type material, with emphasis on diagnostic characters [vegetative characters visible on the original plate ( Doll 1973: Plate XVIII) are not included].

Outer phyllaries few, ca. 8–10, subappressed, not imbricate, ± narrowly to broadly lanceolate, usually 5–6 × 1.5–2.2 mm, light green with purplish distal part, border not distinct, membranous, to 0.2 mm wide, margin ± ciliate. Stigmas greenish yellow (light discoloured). Pollen absent. Achenes dark red-brown, usually 3.0– 3.4 mm long, very slender, ca. 0.6 mm thick, body ± densely and distinctly spinulose above, subabruptly narrowing into a thin cylindrical cone 0.7–0.9 mm long, usually less than 0.2 mm thick; beak 6.5–7 mm long, pappus ± white, 4–5 mm long.

On the basis of the above description, we place T. ustamenum in T. sect. Erythrosperma . The original idea ( Doll 1973: 499) of T. ustamenum as a member of T. sect. Parvula has no support in the morphology of the type plants.