AMORPHOPHALLUS RANCHANENSIS

PROTOLOGUE: Amorphophallus ranchanensis Ipor, A.Simon & Meekiong, published in Folia Malaysiana 8(1): 1 (2007).

Amorphophallus ranchanensis Ipor, Tawan, A.Simon, Meekiong & Fuad Amorphophallus hottae similes, quo appendice breviore dilute rubra et bulbilis intercalaribus ad nodos differt. Amorphophallus ranchanensis pagina murica in spathae parte interiore, petiolo e basi maculas excrescentes guadet. Typus: Malaysia, Sarawak, Serian, Kota Samarahan, Ranchan Recreational Park, 17 September 2006, Simon, Ipor & Meekiong AS 163 (holotype; HUMS, inflorescence and leaf in spirit); same locality and date, Simon, Ipor & Meekiong AS 164 (paratype; HUMS, inflorescence and leaf in spirit).

DISTRIBUTION: Borneo (Sarawak): Borneo.

DISTRIBUTION NOTE: East Malaysia: Sarawak, Serian - Ranchan Recreational Park, near Kota Samarahan. Endemic to Sarawak and, so far, found nowhere else.².

SPECIES DESCRIPTION:

Small to medium-sized herbs, ca. 30-150 cm tall. Tuber depressed globose, no offset development, to 3.5-4.0 cm high, 5.2-6.3 cm diameter, surface brown, inner part fleshy, whitish. Adventitious roots numerous, present on the top part of the tuber, creamy white. Leaf solitary; petioles to 60-70 cm long, diameter 4.8-5.2 mm upper part, 6.4-7.1 mm middle, 7.2-8.4 mm base, greyish purple slightly pinkish with raised, very distinct, broadly oval elongate, sometimes elliptic green spots, the spots excrescent, their margins with raised green punctiform dots; lamina highly dissected, rachises naked, background greyish purple pinkish, scattered with raised green punctiform dots sometimes forming oval elongate-shaped spots; anterior leaf ca. 16.0 cm with only one leaflet, posterior leaf with 5-6 leaflets 26.0-28.0 cm long, branches dichotomously forming leaflets; leaflets broadly elliptic, oblanceolate or obovate, 7.5-20.0 cm long, 2.4-10.0 cm wide, slightly asymmetrical, apex acuminate or apiculate, base oblique or truncate, margin wavy to slightly undulate; adaxial surface green, smooth, slightly glossy, midrib slightly channelled, dark purple, secondary veins flattened; abaxial surface dull pale green with many dark purple spots scattered along the secondary veins, mostly towards the midrib, midrib raised, greyish purple green slightly pinkish, secondary veins raised, light purple green and green; 16-17 pairs of secondary veins looping with reticulate tertiary veins, lamina chartaceous.²

INFLORESCENCE:

Inflorescence solitary, flowering without foliage leaves; peduncle ca. 35.5-67.4 cm long, cylindrical slender, diameter 2.3-6.8 mm upper part, 2.4-10.5 mm middle, 4.2-11.5 mm base, background dark purple with shades of pink greyish purple scattered with white or green very distinct raised spots forming elliptic to elongate oval shapes, inside of the spots pink purple, surface slightly puberulent, slightly glossy; spathe campanulate, reflexed backwards at anthesis, later recurved towards the appendix, elongate slim hour-glass shape, 4.0-16.5 cm long, diameter ca. 20.8 mm base, ca. 25.8 mm middle, ca. 29.8 mm upper part, lower part of spathe strongly campanulate, apex long acuminate, involute; outer spathe background greyish green purple with many dark purple and creamy white spots scattered all over, green along the margin, base slightly pink purple; spathe inside purple at base, very light green yellowish in the middle, dull dark green in the upper part alternating with green, along the margin sometimes dark purple, base to middle densely muricate, light green-yellow; spadix longer than spathe, 22.3-27.5 cm long, stipeless. Appendix 17.0-38.7 cm long, diameter 1.9-5.1 mm upper part, 5.6-8.7 mm middle, 5.7-12.9 mm base, cylindrical, decreasing in diameter towards the apex, apex truncate, base dark purple to maroon purple, from the middle to the upper end pink to pale pink, surface finely verrucose with longitudinal lining, no odour. Flowers monoecious; male zone cylindrical, slightly elongate obovate, 3.5-7.0 cm long, diameter 5.1-11.8 mm upper, 5.6-9.6 mm middle, 5.7-8.7 mm base, dark purple sometimes peach pink, flowers congested to slightly distant; stamens 3-6, ca. 11 mm long, ca. 4 mm wide, fusiform; anthers sessile, 4-5 mm long, 1-1.5 mm wide, purple to pink slightly peach; filaments 0.8-1.0 mm high, 3-4 mm long, light yellow; pollen rounded, yellow; female zone cylindrical, 1-1.8 cm long, diameter ca. 9.6 mm upper, ca. 10.5 mm middle, ca. 10.8 mm base, flowers congested; stigma sessile, 2-3 lobed, rounded, 1.0-1.5 mm long, 1.6-2.2 mm diameter, dark brown to light brown; ovaries bilocular, 3.6-3.8 mm diameter, rhomboidal, rounded, surface pusticulate, green in the upper part, middle part to base very light green, smooth.²

ECOLOGY:

Found on forested sandstone²

ETYMOLOGY:

Named after its type locality, Ranchan Recreational Park at Serian in Sarawak - a place popular with local people for picnics and family gatherings, which is why the authors close the paper by asking the Serian Municipal Council to conserve what remains of the population.²

NOTES:

1. Diagnosis: it resembles Amorphophallus hottae, from which it differs in a shorter, pale red appendix and in intercalary bulbils at the nodes. Amorphophallus ranchanensis has a muricate inner surface to the spathe, and the petiole carries excrescent spots from the base.²

2. Cut the petiole and it bleeds a white, milky, odourless sap almost at once. In other species of the genus that sap is usually transparent, and it is one of the readiest ways to know this plant in the field.²

3. The petiole is further marked by raised, very distinct oval to elliptic green spots whose own margins carry raised green dots - the excrescent spotting the diagnosis singles out.²

4. The type gathering and its paratype were both made at Ranchan Recreational Park on 17 September 2006, and the species has not been found outside that park.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Amorphophallus ranchanensis Ipor, A.Simon & Meekiong

2. Folia Malaysiana 8(1): 1 (2007) — protologue.

3. Alan Galloway — Amorphophallus ranchanensis, alangallowaybotanicals.com.

4. The Aroids of the Sarawak Limestone. Newsletter of the International Aroid Society 31(2): 18 (2009)

Additional photos by Pio Swiat and Bruno Antont (Leiden Botanical Garden)