Carex × binderi Podp., Oesterr. Bot. Z.

Řepka, Radomír & Taraška, Vojtěch, 2023, Typification of three Carex nothospecies names dedicated to Czech botanists by J. Podpěra, Phytotaxa 618 (2), pp. 172-180 : 173-175

Carex × binderi Podp., Oesterr. Bot. Z. 50: 212, 1900.

= Carex ×leutzii Kneucker [ C. hostiana DC. × C. lepidocarpa Tausch ], Seubert, Excurs.-Fl. Baden, ed. 5: 68, 1891.

Lectotype (designated here): “ Bohemia: In pratis Hrabanov pr. Lysá n. L.”, June 1899, leg. J. Podpěra, BRNM no. 166217 ! [rev. R. Řepka 2023 as Carex hostiana × C. lepidocarpa = C. ×leutzii ] ( Fig. 1 ).

Isolectotype: BRNU no. 403278 ! [sub Carex distans × lepidocarpa = C. binderi Podp. ].

Carex ×binderi was the first Carex hybrid name published by J. Podpěra and dedicated to his friend and field guide, Emil Binder (1860–1939?). He was custodian of the herbarium of the Natural Sciences Club in Prague, who issued exsiccates for sale and therefore collected plants all over Bohemia ( Klášterský et al. 1982). It was very likely E. Binder who informed J. Podpěra about the existence of remarkable hybrid plants at the locality of Hrabanov. Subsequently, J. Podpěra described them as C. × binderi , which he considered a hybrid between C. distans L. 1759: 1263 × C. lepidocarpa Tausch 1834: 179 [sub C. flava var. lepidocarpa (Tausch) Godron 1844: 118 ]. According to the protologue, C. × binderi was observed in two robust tussocks at the type locality, where it co-occurred with several other Carex taxa, namely C. hornschuchiana Hoppe 1824: 595 (= C. hostiana DC. 1813: 88 ), C. hostiana × C. lepidocarpa , C. buxbaumii Wahlenberg 1803: 163 , and C. stricta Goodenough 1794: 196 (= C. elata Allioni 1785: 272 ). We managed to find two specimens of C. × binderi collected by J. Podpěra and equipped with labels bearing his handwriting, one in BRNM and the other in BRNU. The latter was indicated as holotype by W.J. Crins in 1984, but this is not in congruence with the ICN ( Turland et al. 2018, Art. 9.1.). Instead, both specimens should be regarded as syntypes until a lectotype is designated (Art. 9.6.). Here we selected the specimen in BRNM as lectotype, making the specimen in BRNU an isolectotype.

The plant selected by us as the lectotype predominantly shows the features of C. hostiana : rhizomes with extravaginal shoots having partially fibred whitish grey sheaths, oval female spikes with utricle beak 1.1–1.5 mm long, directed slightly obliquely upwards, stem length ca 70 cm, sheaths under lower female spikes 19–20 mm long, presence of a stem-like leaf in about the middle of the stem. However, the light rusty colour of the glumes of the female spikes rather corresponds to C. lepidocarpa . Also the purple sheath on the rhizome, which can in one case be observed on the C. × binderi type specimen, is typical of C. lepidocarpa , but not of C. distans or C. hostiana . The fertility of the plant is very low: utricles are fully developed, but achenes are missing. The features of utricles and its beak fully correspond to C. hostiana .

In addition, no features of C. × binderi correspond to C. distans , which was identified by J. Podpěra as one of the parental species. In fact, the plant of C. × binderi is morphologically closer to C. hostiana than C. distans , which may be characterised by brown to reddish brown lower sheaths on the shoots, relatively long and wide bracts under the lower female spike (33–86 × 2.4–3.9 mm vs 34–45 × 1.8–2.7 mm in C. hostiana ), and bracts under lower female spikes with a relatively long sheath (19–44 mm vs 9–26 mm in C. hostiana ). Furthermore, the beak of C. × binderi is cylindrical, less incised than in C. distans , and the teeth are close together. In C. distans , the utricle beak is flat and broad with massive and widely spaced teeth (comparison based on unpublished data). Two more traits mentioned in the protologue ( Podpěra 1900) are shared by C. distans and C. hostiana , namely a rounded stem and the presence of an antiligule. By contrast, the dirty yellow-brown colour of the lower sheaths mentioned in the protologue does not agree with the real state, as they are whitish grey, partly disintegrating into dark grey fibres in the type specimen.

For the above-mentioned reasons, we consider the plants of C. ×binderi to be taxonomically identical with C. × leutzii , a formerly relatively common hybrid of C. hostiana and C. lepidocarpa , which used to grow in fens with both parental species if they found suitable ecological conditions there. In the Czech Republic, this nothospecies is recently very rare, but it can survive at localities even in absence of both parental species, which are strongly sensitive to landscape changes and considered threatened ( Grulich 2017). This hybrid may somewhat resemble C. distans in the shape and distance of the lower female spike as well as other features mentioned above, which may have been confusing for J. Podpěra as well.

Figures

FIGURE 1. Lectotype of Carex ×binderi Podp. (BRNM 166217).