ARUM BESSERIANUM
PROTOLOGUE: Arum besserianum , published in Österreichische Botanische Zeitschrift 8: 349 (1858).
Arum Besserianum. Folii lamina sagittata, lobis posticis lateraliter parum prominulis. Organa neutra ab antheris remota, inferiora pauca, superiora sub 4-cycla. Stipes appendicis clava ellypsoidea, ⅓ — ¼ totius spadicis metiente longior. Habit. in Volhinia. (Besser.) Von Arum orientale Biebrst., zu welchem Besser die volhinische Pflanze letztlich zog, durch Kürze und Form der Keule verschieden. Denn Ar. orientale (wenigstens das caucasische) zeigt eine stumpfe cylindrische Keule, die länger als ihr Stiel ist.
SYNONYMS:
HOMOTYPIC SYNONYMS: Arum maculatum subsp. besserianum (Schott) Nyman; Arum orientale subsp. besserianum (Schott) Holub
HETEROTYPIC SYNONYMS: Arum besserianum f. miodoborense (Szafer) Terpó; Arum besserianum var. miodoborense Szafer
DISTRIBUTION: S. Poland, Ukraine: Poland, Ukraine.
DISTRIBUTION NOTE: iNaturalist: Cherkasy, Chernivtsi, Khmelnytskyi, Kyiv, Vinnytsia.
SPECIES DESCRIPTION:
Tuberous geophyte. Tuber globose and compressed, much in the manner of a begonia tuber, the new tuber forming directly above the old one, so that successive seasons of growth do not build the obliquely globular, offset tuber of Arum orientale nor the elongated, laterally creeping, sausage-like rhizome of Arum maculatum. Leaf blade sagittate, the posterior lobes only slightly prominent laterally.
INFLORESCENCE:
Inflorescence held beneath the leaves. Spathe more deeply colored than in Arum orientale. Sterile flowers densely arranged, the staminodes remote from the anthers, the lower ones few, the upper in about four whorls; this arrangement is the character on which Szafer founded var. miodoborense. Appendix club ellipsoid, measuring ⅓–¼ of the whole spadix and shorter than its own stipe — the difference on which Schott separated the species from Arum orientale, in which the club is bluntly cylindric and longer than its stipe.
ECOLOGY:
Temperate zone of southern Poland and Ukraine; the type was gathered in Volhynia and the species was later found in the Ukrainian Carpathians.
ETYMOLOGY:
For Wilibald Besser (1784–1842), who collected the Volhynian plant and referred it to Arum orientale; Schott separated it in 1858 and named it for him, citing “(Besser.)” with the diagnosis.
NOTES:
1. Schott founded the species in 1858 on plants Wilibald Besser had gathered in Volhynia and referred to Arum orientale, separating it on the short, ellipsoid appendix club, which is shorter than its own stipe.⁶
2. Boyce treated it as insufficiently known in 1993, and Riedl had earlier reduced it to a synonym of Arum alpinum. Reviewing the group again in 2006 from plants in cultivation, Boyce concluded that it is quite distinct from Arum orientale and probably not closely related to it: the tuber is globose and compressed, and the new tuber forms directly above the old, whereas that of Arum orientale is set slightly to one side and builds an apparently elongated body over several seasons.⁸
3. Its pollinator has never been recorded. Scanning electron microscopy places its trap micro-anatomy inside the midge-pollinated cluster, so midges are the expectation — but this is a morphological prediction, not an observation.⁹
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Arum besserianum
2. Österreichische Botanische Zeitschrift 8: 349 (1858) — protologue.
3. iNaturalist: Arum besserianum
6. 2006. Studies on the Genus Arum (Araceae).
7. Delpino 1874. Ulteriori osservazioni e considerazioni.
8. Boyce, P.C. 2006. Arum – a decade of change. Aroideana 29: 132–137.
Additional photos by David Scherberich