ARUM HYGROPHILUM

Species

PROTOLOGUE: Arum hygrophilum , published in Diagnoses Plantarum Orientalium Novarum 13: 8 (1854). The protologue is reproduced below.

SYNONYMS:

HETEROTYPIC SYNONYMS: Arum albinervium Kotschy ex Engl.; Arum hygrophilum subsp. aurorum Braun-Blanq. & Maire; Arum hygrophilum subsp. maurum Braun-Blanq. & Maire; Arum hygrophilum var. albinervium Kotschy ex Engl.; Arum hygrophilum var. maurum (Braun-Blanq. & Maire) Jahand. & Maire; Arum longicyrrhum Schott

DISTRIBUTION: NE. Morocco, E. Cyprus, W. Türkiye, SW. Syria N. & C. Israel and W. Jordan: Cyprus, Israel, Jordan, Lebanon, Morocco, Palestinian Territories, Syria, Türkiye.

SPECIES DESCRIPTION:

Tuberous herb sprouting in early autumn from a discoid vertically (rarely horizontally) orientated tuber 3-6 cm across, 1.5—2.5 cm thick. Petiole terete, 9-75 cm long, 3-6 mm wide, bright mid-green, occasionally with purple staining along the sheath margin and at the petiole base. Leaf-blade lanceolate-hastate, apex acute to subacute, 8—45 cm long, 5-14 cm wide, dark to bright mid-green

INFLORESCENCE:

Inflorescence unscented. Peduncle shorter than the leaves, terete, 15–45 cm long, 1.5–4 mm thick, bright mid-green. Spathe 7–14 cm long; spathe-tube ellipsoid, 2.5–3.8 cm long, 1.2–2.5 cm wide, waisted above, exterior pale to mid-green, occasionally with purple staining at the base and along the margin, rarely with the entire spathe-tube stained purple, interior deep purple, often with pale greenish white blotches on the rear wall near the base; spathe-limb oblong-lanceolate to elliptic-lanceolate, 5–11.5 cm long, 3–3.5 cm wide, erect to slightly cucullate, acuminate, externally pale to mid-green, purple-flushed along the margin, internally pale greenish white with a purple margin 0.5–1.5 mm wide. Spadix ⅔ as long as the spathe-limb, 7.5–9.5 cm in total length; appendix slender-cylindric, without a stipe, 5–7.5 cm long, 1.5–3 mm wide, deep purple, occasionally blotched apically with paler purple. Staminodes in 2 or 3 whorls, forming a zone 2–3.5 mm long; bristles filiform, flexuous, 4–5 mm long, pale cream, ± purple at the tip; bases conic, verrucate, cream, stained with purple. Interstices: upper 0–2 mm long, longitudinally ridged, cream; lower ± absent. Staminate flowers is a roughly quadratic zone 4–7 mm long, 5–6 mm wide; anthers and connectives reddish purple. Pistillodes in 2 or 3 whorls forming a zone 2–3 mm long; bristles filiform, flexuous, cream, stained with purple; bases bulbiform, minutely verrucate, cream, speckled with purple. Pistillate flowers in a cylindric cluster 4–10 mm long; ovaries oblong-fusiform, pale lime-green with a faint purple ring around the stigma; stigma white. Fruiting spike oblong-cylindric, 4–6 cm long, 2–2.5 cm wide; berries angular-pyriform, 4–11 mm long, 3–5 mm wide.

ECOLOGY:

Stream-sides, ditches, wet flushes, damp soil pockets at rock bases; altitude: 0-900 m

DISTRIBUTION MAPS:

ETYMOLOGY:

Greek hygros, “moist”, and philos, “loving”, for its habitat — stream-sides, ditches and wet flushes, an unusual choice in the genus.

NOTES:

1. Pollinated by midges of the Psychodidae. The midges are held for the full anthesis of about ten days, and only males have been recorded.¹²

2. It has the smallest papillate cells of any species examined — 8.00 ± 1.70 µm on the central appendix — and an unusually low count of elongated sterile flowers for a midge-pollinated species. The reduced surface is what earlier observers described as flies running freely inside the chamber; the trapping structures are present, only small.¹²

3. Every vouchered Cypriot record of this species was treated as Arum sintenisii by Boyce in 2006; its absence from Cyprus remains uncertain.⁵,¹⁵

4. The species description above records the inflorescence as unscented. In Lebanon, at about 1,800 m on the western summit of Dschebel Keneise, flowers of this species were reported to have a carrion odor that drew very large numbers of flies. This is a single, unquantified field observation, not a pollination test.¹³

5. James Waddick grew Arum hygrophilum for more than ten years in the Kansas City area (USDA Zone 5/6, with extended droughts and low rainfall). After a couple of nights at 15 °F the foliage was still undamaged, though colder nights were expected to bring further foliage damage; the plants recovered in spring and flowered regularly, and he found them reliable and hardy there.¹⁴

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Arum hygrophilum

2. Diagnoses Plantarum Orientalium Novarum 13: 8 (1854) — protologue.

3. iNaturalist: Arum hygrophilum

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.

6. Chartier et al. 2013. Geographical variations of odour and pollinators, and test for local adaptation by reciprocal transplant of two European Arum species. Functional Ecology.

7. Diaz et al. 2006. The effectiveness of some mechanisms of reproductive isolation in Arum maculatum and A. italicum (Araceae). Botanical Journal of the Linnean Society.

8. Linz et al. 2010. Molecular phylogeny of the genus Arum (Araceae) inferred from multi–locus sequence data and AFLPs. TAXON.

9. Albre et al. 2003. Pollination ecology of Arum italicum (Araceae). Botanical Journal of the Linnean Society.

10. Delpino 1874. Ulteriori osservazioni e considerazioni.

11. Gibernau et al 2003. Arum Pollen longevity & viability.