ARUM MEGOBREBI
PROTOLOGUE: Arum megobrebi , published in Willdenowia 37: 447 (2007).
Arum megobrebi Lobin, M. Neumann, Bogner & P. C. Boyce, sp. nov. Ab Aro maculato foliis duobus (versus foliis 4-6) et spadicis appendice elongate cylindrica vel raro leviter clavata, haud stipitata (versus valde clavata, distincte stipitata) differt. Holotype: Georgia, Imeretia, westside of Surami Mountains, near Chewi, W of street-tunnel, W of the pass, 42°4.863'N, 43°28.520'E, 690 m, 25.5.2007, A. Gröger & W. Lobin (TBI; isotypes: B, BM, BONN, E, FR, K, LE, M).
DISTRIBUTION: NE. Türkiye to Transcaucasus: Armenia, Azerbaijan, Georgia-GE, Türkiye.
SPECIES DESCRIPTION:
Seasonally dormant slender herbaceous plant to 40 cm tall. Shoots usually with only two leaves and beginning growth in early spring. Stem a horizontal rhizomatous tuber, 3.5–5 cm long and (1–)1.5–2 cm in diam., brown outside, not clump-forming and always growing solitary; roots on apical part of tuber. Petioles (18–)19–30(–40) long, 2–3 mm in diam. above and 3–4 mm below, flattened on upper side, green to reddish tinged or red, especially on lower part; sheath 6–9(–12) cm long and to 5 mm wide. Leaf blades ± sagittate to hastate (somewhat variable), 7–13(–17) cm long and 5–8(–10) cm wide, apex acute and only rarely obtuse, basal lobes obtuse to acute; venation reticulate, midrib strong, 4–5(–6) primary lateral veins on each side.
INFLORESCENCE:
Inflorescence solitary, foul-smelling. Cataphylls (4–)6–12(–18) cm long, membranaceous. Peduncle (5–)6–12(–15) cm long and 2–2.8 mm in diam., terete, rarely green but mostly reddish to red, shorter than petioles. Spathe (10–)12–15(–17) cm long, constricted, outside greenish to whitish green, inside the same colour, margin often reddish, or outside and inside purplish tinged (some specimens); (lower) tube convolute, (1–)1.5–2 cm long and 1–1.5 cm in diam., inside whitish and with a broad ringlike purple zone or nearly completely purple, constriction 0.8–1 cm in diam.; limb 8–14(–15) cm long and 2.5–3 cm wide in the middle, apex acuminate. Spadix much shorter than spathe, 8–10 cm long; female zone 0.7–0.8 cm long and c. 0.5 cm in diam.; sterile flowers between female and male flowers in 2 circles or rows, this zone c. 2 mm long; male zone c. 0.4 cm long and 0.4 cm in diam.; sterile flowers above male flowers in c. 3 spiral rows and this zone c. 3 mm long; appendix elongate-cylindric (not stipitate and never strongly clavate, only rarely very slightly clavate), (5–)6–8 cm long and 2–3 mm in diam., smooth, purple. Infructescence with (13–)19–21(–25) orange-red berries.
ECOLOGY:
Deciduous mixed forest, the tree layer dominated by Fagus orientalis, Carpinus orientalis and Acer trautvetteri; altitude: 200-2400 m
ETYMOLOGY:
In Georgian the epithet “megobrebi” means “friend”. The first author chose the name to honour the relations between the botanical gardens of Tbilisi, Bonn and Munich, in close cooperation since 1999.
NOTES:
1. Its pollinator is unrecorded; its trap micro-anatomy falls inside the midge-pollinated cluster, which is a prediction rather than an observation.⁷
2. It is unusual in the genus for having no papillae at all on the central spathe blade, while retaining them in the upper chamber; the lower chamber has convex cells with small lacunae in the corners.⁷
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Arum megobrebi
2. Willdenowia 37: 447 (2007) — protologue.
3. iNaturalist: Arum megobrebi
5. Lobin et al 2007. Arum megobrebi - [Willdenowia 37, 445-449].
6. Delpino 1874. Ulteriori osservazioni e considerazioni.