ARUM ORIENTALE
PROTOLOGUE: Arum orientale , published in Flora Taurico-Caucasica 2: 407 (1808). The protologue is reproduced below.
DISTRIBUTION: EC. Europe to W. Caucasus: Albania, Armenia, Austria, Azerbaijan, Bosnia and Herzegovina, Bulgaria, Croatia, Czechia, Georgia-GE, Greece, Hungary, Israel, Jordan, Kosovo, Krym, Lebanon, Montenegro, North Caucasus, North Macedonia, Palestinian Territories, Poland, Romania, Serbia, Slovakia, Slovenia, South European Russia, Syria, Türkiye, Türkiye-in-Europe, Ukraine.
DISTRIBUTION NOTE: iNaturalist: Blagoevgrad, Giurgiu, Mehedinți, Plovdiv.
SPECIES DESCRIPTION:
Tuberous herb sprouting in mid-autumn to late autumn from a discoid, horizontally orientated tuber 4—6 cm across, 2—2.5 cm thick. Petiole terete, 18-46 cm long, 3—7 mm wide, deep green, usually stained with purple, especially towards the base. Leaf-blade broadly hastate, apex obtuse to subacute, 8.5-25 cm long, 5.5—17 cm wide, deep green
INFLORESCENCE:
Inflorescence smelling moderately of horse-dung (subsp. orientale, subsp. longispathum) or sweet, fermenting (subsp. sintenisii). Peduncle much shorter than to almost equalling the leaves, terete, 11-19 cm long, 3-4 mm wide, deep green, sometimes stained with purple. Spathe 14.5—30 cm long; spathe-tube oblong-cylindric, 2.5—5.5 cm long, 1.5-2.5 cm wide, constricted apically, exterior mid-green with dull purple staining towards the margin and apex, fading to greenish white at the base, interior greenish white below, purple above; spathe-limb ovate to ovate-lanceolate, 12—24.5 cm long, 4—7 cm wide, erect at first but the apex soon flopping forwards, acute to rather bluntly acute, externally pale to mid-green, heavily to moderately stained purple, median vein pale green, internally similarly coloured, but with much heavier purple staining, apex mid-green. Spadix ⅓–½ as long as the spathe-limb, 5.5—16 cm in total length; appendix slender-clavate to cylindric, long-stipitate or stalkless, 3.5—13: cm long, 3.6-6.5 cm wide, dull mid-purple, stipe when present generally paler. Staminodes in c. 2 whorls forming a zone 4—7.5 mm long, yellow, flushed with purple; bases conic, + smooth, yellow. Interstices: upper 2.5-4 mm long, ° sparsely grooved, minutely verrucate, yellow; lower + absent. Staminate flowers in an quadrate zone 2-5.5 mm long, 3-5 mm wide; anthers yellow with purple tips, connectives yellow. Pistillodes in 3 or 4 whorls forming a zone 3-7 mm long; bristles filiform, flexuous, 2.5-6 mm long, yellow, flushed with purple; bases compressed conic, smooth, deep yellow. Pistillate flowers in a globose-cylindric cluster, 4.5—20 mm long; ovaries globose, 1.5-2 mm long, dull oblive-green, stained with purple apically; stigma papillose, green. Fruiting head cylindric, 4—5.6 cm long, 2-2.5 cm wide; berries oblong, 5~10 mm long, 3.5-5 mm wide
ECOLOGY:
sea-level to 950 m; altitude: 0-950 m
DISTRIBUTION MAPS:
ETYMOLOGY:
Latin, “eastern”, for its range east of the main European species.
NOTES:
1. The inflorescence is carried below the foliage, and smells of cattle dung and urine.⁵
2. Two taxa Boyce treated in 1993 as subspecies of this species were raised to species in 2006: Arum longispathum and Arum sintenisii.⁵
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Arum orientale
2. Flora Taurico-Caucasica 2: 407 (1808) — protologue.
3. iNaturalist: Arum orientale
4. Boyce, P.C. 1993. The Genus Arum: a Kew Magazine Monograph. Royal Botanic Gardens, Kew.
5. Boyce, P.C. 2006. Arum – a decade of change. Aroideana 29: 132–137.
9. 2006. Studies on the Genus Arum (Araceae).
10. Gibernau et al 2003. Arum Pollen longevity & viability.
11. Croat T.B 1989. Ecology and Life Forms of Araceae a Follow-up.