ALOCASIA AZLANII
ORIGINAL DESCRIPTION:
Alocasia azlanii K. M. Wong & P. C. Boyce, sp. nov. Alocasia azlanii has similarities to Alocasia beccarii and Alocasia peltata in being small herbs with peltate glabrous leaves; Alocasia azlanii differs from Alocasia beccarii by the conspicuous marginal and intramarginal veins of its leaf blades (A. beccarii has only a clear marginal vein), from Alocasia peltata by the interprimary collective veins formed by confluent secondary veins in the leaf anterior lobe (Alocasia peltata does not have confluent secondary veins) and the staminate zone of its spadix being only partially within the lower spathe chamber (in Alocasia peltata the staminate zone is entirely within the lower spathe chamber), and from both in its occurrence in mixed dipterocarp forest (the other two species are found in kerangas forest, with Alocasia peltata only occurring above 800 m asl).
Typus. BRUNEI, Tutong District: Rambai, Ladan Hills Forest Reserve, Benutan Dam catchment forest, tributary of Sungai Benutan, alluvial forest, 7 June 2015, flowering, K. M. Wong, Azlan & Jangarun WKM 3433 (holotype BRUN, isotype SING).
SYNONYMS: N/A
DISTRIBUTION: Indonesia | Borneo | Brunei (Tutong District)
CLIMATE: Equatorial lowland humid forest
Humidity is consistently high in the lowlands ranging from 80% to 90%
Temperature is relatively uniform throughout the year - within the range of 73°F/23°C early in the morning to 90°F/32°C during the day. Minimum temperatures in the lowland areas don’t generally dip below 68°F/20°C
The average rainfall per year is between 3,300 millimetres and 4,600 millimetres, depending on locality.
ECOLOGY: Well-shaded moist ground above flood level on banks of a shallow tributary of the Benutan river, which drains mixed dipterocarp forest on sandy clays
SPECIES DESCRIPTION:
Herbs, 10–28 cm tall (Fig. 1). Stem slender, 8–10 mm in diameter, condensed with the internodes nearly as wide as long. Leaves several, together, interspersed with lanceolate cataphylls to c. 6 cm long, drying brown; petiole pale green, glabrous, sheathing in the lowest 1/7 or less; blade (Fig. 1, 2A) broadly ovate-elliptic, 16–20 × 8.5–11 cm, upper surface dark coppery purplish green, lower surface pale green, thinly coriaceous, spreading to sub-pendent; anterior lobe widest, usually c. a fifth to a quarter the distance distal to petiole insertion; margin somewhat broadly sinuate; anterior costa with 2 or 3 primary lateral veins on each side, diverging at c. 45–60º and upcurving into a conspicuous intramarginal vein 2–4 mm from the margin and inner to a marginal vein; primary lateral veins prominent on both surfaces of the blade; secondary venation confluent and forming interprimary collective veins; posterior lobes almost completely united save for a 4–8-mm incision at the extreme base of the leaf; combined posterior lobes cuneate, 5–7 cm long.
INFLORESCENCE:
Inflorescence (Fig. 1, 2B) solitary; peduncle slightly shorter than petiole at anthesis, c. 6.5 cm long, 2.5 mm in diameter; spathe c. 6 cm long; lower spathe narrowly ovoid, c. 2.8 cm long, 1.1 cm in diameter, separated from limb by a weak constriction; limb c. 3 cm long, lanceolate, pale green or nearly white; spadix shorter than the spathe, c. 5 cm long, 1.5 mm diameter at the base, stipitate for c. 1–2 mm; carpellate zone (Fig. 2C) c. 12 mm long; pistils arranged in 5 or 6 spirals, white; ovaries subglobose, sessile, c. 1.5 mm diameter, glabrous; style c. 0.5 mm long, 0.5 mm in diameter, with 3 conjoined sub-triangular stigmatic lobes each c. 0.5 mm long and 0.5 mm wide at base; sterile interstice c. 2 mm long; synandroidea more or less clavate, c. 1.5 mm wide, white; staminate zone (Fig. 2B) partially held within lower spathe, c. 16 mm long including c. 5 mm portion above spathe constriction; synandria rhombo-hexagonal, with sinuous margins, c. 1.5–2 mm wide, white; thecae mostly in pairs, not concealed by synconnective; appendix somewhat isodiametric with staminate zone at base, subcylindric, tapering in upper third, c. 2.4 cm long, white. Peduncle of infructescence c. 10.2 cm long, 3.5 mm in diameter. Persistent lower spathe c. 4.1 cm long, 1.8 cm in diameter; fruits (Fig. 2D) globose, sessile, to c. 8 mm in diameter, glabrous, glossy white.
VARIEGATED FORMS: WHITE; MOTTLED
NOTES: Alocasia azlanii was named after plant collector Azlan Pandai of the Brunei National Herbarium, whose enthusiasm in searching out aroids in the field has brought about many rewarding finds.
CULTIVARS: N/A
HYBRIDS: N/A
