Rubus slavonicus Király, Trávníček & Žíla, 2015

Király, Gergely, Trávníček, Bohumil & Žíla, Vojtěch, 2015, Rubus gayeri and Rubus slavonicus, two new species of Rubus ser. Micantes (Rosaceae) from Central and South-Eastern Europe, Phytotaxa 195 (4), pp. 279-290 : 283-284

Rubus slavonicus Király, Trávníček & Žíla , sp. nova

Type:— HUNGARY. Somogy County, Kaszó, 0.2 km W of the settlement, pedunculate oak wood ; N46.320127°; E17.218524°; 172 m, 7.9.2013, fruiting, G. Király & D. Schmidt (holotype: BP732259, isotype: BP733732, BP733733, GJO, GZU, OL, W, ZA)

Description: Shrub, usually up to 80 cm tall. First-year stems low-arching, rooting at apex, bluntly angled, 3–7 mm in diameter. Sides ± flat, dull green, in sunny places suffused red-brown, with 10–30 ± patent hairs 0.2–0.6 mm long per 1 cm length of stem side and with numerous sessile glands; stalked glands (ca. 0.5 mm long) very scattered or absent. Prickles 7–15 per 5 cm length of stem, usually on angles, strongly compressed, gradually broadened at the base up to 5 mm, distinctly to strongly curved, 3–6(–7) mm long, yellowish or often reddish. Leaves palmate, 5-foliolate, usually dark green, with up to 50 appressed hairs per cm 2 above when young, later often glabrescent; greyish-green beneath with dense stellate hairs. Terminal leaflets with petiolules 22–36% as long as its lamina, ovate, rounded or indistinctly cordate at the base, with a gradually tapering apex 20–25(–30) mm long. Basal leaflets ovate, with petiolules 2–6 mm long, (0.8–)0.9–1.4× as long as the petiole. Indentation regularly or often irregularly periodic, with incisions 1–3(–4) mm deep, teeth ± triangular. Petioles hairy, with several sessile glands and scattered stalked glands of different length; and with 10–22 curved prickles. Stipules 0.4–0.6 mm broad, with eglandular hairs and stalked glands. Inflorescence paniculate, its form various , conical, pyramidal or cylindrical, with erecto-patent branches; distal 5–10 cm leafless, then with 1–2 simple or divided leaves, below with 3-foliolate leaves; inflorescence leaves with often deeper indentation; their indumentum is similar to those of the sterile stems. Inflorescence axis densely pilose, with (5–)10–60(–100) stalked glands per 1 cm length. Terminal part of the inflorescence axis with few 1–3 mm long, rather slender, slightly curved, distant or indistinctly declining prickles. Lower part of the inflorescence with 3–8 prickles per 5 cm length of inflorescence axis; prickles strongly curved and declining, 3–5 mm long. Pedicels 1–2(–2.5) cm long, densely pilose, with (2–)5–20(–50) stalked glands; pricklets 7–15, ± straight, 0.5–2 mm long. Sepals 5–8 mm long, ovate-lanceolate, whitish-greyish-felted with stellate hairs; with sparse stalked glands and few slender pricklets, strikingly stellate-patent after anthesis, later often reflexed. Petals not touching each other, white, ± spathulate, 6–9 mm broad and 10–13 mm long, rounded at the apex. Stamens longer than the light green styles; anthers glabrous, yellow, filaments whitish. Ovaries sparsely pilose, rarely near glabrous. Receptacle pilose. Flowering VI–VII.

Iconography and photos of the species are shown in Figures 3 and 4 .

Taxonomical remarks: Rubus slavonicus distinctly differs from R. clusii by the lack of stalked glands on the sterile stem, the lower number of prickles on the inflorescence axis and the position of sepals; also shape and some dimensions of leaf are (with overlaps) dissimilar. It is also easily told from R. balatonicus by the lower number of prickles on the sterile stem, and by the length and position of sepals. Nevertheless, it is rather similar to R. ambulans Matzk. 2004: 28 (described from western central Europe, with easternmost localities in Bavaria; Matzke-Hajek 2004). The main diagnostic characters of R. slavonicus against R. ambulans are the presence of stalked glands on the inflorescence axis and pedicels, the position of sepals after anthesis (patent versus reflexed) and the different serration of leaflets (periodic verus regular) (see also Table 2).

Etymology: The epithet refers to the historical region “Slavonia” in north-eastern Croatia.

Distribution: We recorded only two older herbarium specimens of the species (collected in the vicinity of Barcs, SW Hungary, where it has been found recently as well; these specimens in PECS were formerly misidentified as “ R. gremlii Focke ”), thus, we characterize its range predominantly based on own collections and observations. Rubus slavonicus is a regional bramble species with some tendency to a wide distribution, with a specific long-drawn range (approx. 250 km long and 50 km broad in N-S direction) from the northwestern Balkans to the centre of the Pannonian Basin. Its southernmost locality was found in northern Bosnia, and the northernmost ones are located near Uzsa in Transdanubian Mts (Dunántúli-középhegység), central Hungary ( Figure 5b , Appendix 2). It is scattered (but locally abundant) in Belső- Somogy region (southwestern Hungary). In Croatia, it was recorded in significant number in the borderland of western Slavonia (Gornjoposavska mezoregija).

Ecology and biogeography: R. slavonicus is a thermophilous and heliophilous bramble usually growing in sunny habitats (forest fringes, roadsides, clearings and young crops). It prefers nutrient- and base-rich, semi-dry to moist soils, and is most abundant in areas covered by alluvia or tertiary sandy sediments. Throughout its range it typically occurs in pedunculate oak-hornbeam forests ( Figure 6b ) of lower altitudes with several sub-Mediterranean elements (e.g. Euphorbia dulcis L., Lamium orvala L., Primula vulgaris Huds. , Tamus communis L.). In the northernmost, isolated part of the range (Keszthely Mts north of the Lake Balaton) it is found in extrazonal beech stocks on basalt bedrock. Typical companion species of bramble in Croatia and southwestern Hungary are several biotypes of ser. Discolores and ser. Vestiti (Chaboiss.) Focke (1877: 285). In Keszthely Mts it grows together with several taxa of ser. Discolores, with R. macrophyllus Weihe & Nees 1824: 35 , and with closely related taxa of ser. Micantes ( R. balatonicus and R. clusii ), thus, this mountains is an evident “hot-spot” of the latter group in this region.

Figures

FIGURE 3. Drawings of Rubus slavonicus: (a) inflorescence; (b) leaf; (c) margin of terminal leaflet; (d) axis of inflorescence; (e) peduncle; (f) detail of flowers; (g) petal. Del. J. Táborská

FIGURE 4. Photos of Rubus slavonicus: (a) First-year branch with typical leaves (loc.: S Hungary, Ötvöskónyi); (b) Inflorescence with typical stellate-patent sepals after anthesis (loc.: central Hungary, Uzsa)

FIGURE 5. Distribution maps: (a) Rubus gayeri; (b) Rubus slavonicus

FIGURE 6. (a) Typical habitat of Rubus gayeri: Scots pine plantation with monodominant carpet-like occurrence of the species (loc.: W Hungary, Szentpéterfa, locus classicus); (b) Typical habitat of Rubus slavonicus: Lowland pedunculate oak wood (loc.: S Hungary, Kaszó, locus classicus).