For me, this Alocasia is distinguished most of all by the very fine peach-fuzz on the petioles and leaf reverses; this is entirely uncharacteristic of the well known large Alocasia species such as A. odora and A. macrorrhizos. At a distance, one could mistake this plant for one of those but Alocasia connoisseurs will have no trouble telling the differences.
The inflorescences are similar to those on Alocasia species that seem very different from this one, such as A. reginae 'Miri' and A. scabriuscula. While we have not yet been successful in setting hybrid seed on the A. sarawakensis, the pollen from this plant has produced seed set on some differing species such as A. odora.
The Alocasia sarawakensis is completely green in color, with not the slightest hint of color except for some sparse purplish spotting on the lower portion of the spathes on the white inflorescences, and on the green petioles.
Above picture shows a close-up of a petiole of A. sarawakensis, with the spotting clearly visible.