Homalomena wallichii Schott

Among the first major listing of plants including aroids, collected from "Malaya" (that is to say modern Peninsular Malaysia and Singapore) was that of Danish surgeon Nathaniel Wallich (1786-1854). Wallich came to the then-Danish settlement of Frederiksnagore, near Serampore, Bengal, India in 1807 as a Medical Attache. During the Napoleonic Wars, in which Denmark sided with Napoleon, the British East India Company took over Frederiksnagore, and Wallich was briefly imprisoned. On his release, and after spell as an Assistant Surgeon in the British East India Company's service, Wallich was appointed Assistant to William Roxburgh, the East India Company's botanist in Calcutta. Then in 1817 Wallich was temporarily appointed Superintendent of the Calcutta garden, a post that was later confirmed. Wallich served until 1846, during which time he traveled extensively on botanical explorations, and compiled a catalog of more than 20,000 specimens entitled A Numerical List of Dried Specimens of Plants in the East India Company's Museum - known informally as the 'Wallich Catalog'. Wallich's catalog includes plants from virtually all of the Asian part of the then British Empire, including not only his own collections from Pinang and Singapore made in 1822, but also specimens collected mainly in 1819 on Pinang by William Jack (1795-1822), and by George Porter of the East India Company's Garden at Calcutta, who accompanied Wallich to Singapore in 1822 and later (1823-1834) remained in Pinang, at first as a schoolmaster and latterly in charge of the newly founded Botanic Garden near Ayer Hitam, the modern Penang Botanic Gardens. Some of the aroids listed in Wallich's Catalog were worked up by Roxburgh (1820, 1832) and Jack (1820), while the pioneering aroid botanist Heinrich Schott also took a hand, in 1859 describing a new species of Homalomena in honor of Wallich based on material collected 37 years previously on Pinang. In the main it was left to Joseph Dalton Hooker (1817-1911), with considerable (and for the record not at all generously acknowledged) assistance from Nicholas Edward Brown (1849-1934), to incorporate them into a cohesive account within the Flora of British India (Hooker, 1893). In so doing they produced the first ever account of the aroids of modern West Malaysia. The Homalomena that Schott described in 1859 was called H. wallichii. The specimen upon which he based the name was collected by Wallich on Pinang in August 1822. It is highly distinctive species, not least owing to the remarkably long peduncle and the posture of the leaf blades, and unusually for the time, the herbarium material is in excellent condition (Plate 1). Given that at that time there were only 13 Homalomena species described in total, and that only two were originated for 'Malaya' there should not have been cause of confusion. However, this was not to be the case. Engler (1879) maintained H. wallichii, but the origins of the taxonomic demise of H. wallichii may be traced to Hooker (1893). For reasons that are still far from clear, in particular since Hooker would have had unlimited access to the type specimen, Hooker included H. wallichii, (together with H. major Griff., H, minor Griff., both now species dubiae) in the synonymy of Javan H. coerulescens Jungh. ex Schott, a species not present in the Peninsula. Notwithstanding that H. minor and H. major (both Griffith, 1851a, 1851b) have priority over H. coerulescens (Schott, 1856), it is worth here relating that virtually all material determined by Hooker as H. coerulescens represent novel taxa. Ridley's precursory account for Peninsula Malaysia (Ridley, 1907) aroid treatment follows that of Hooker (1893) with a few exceptions, including the reduction of H. pontederiifolia Griff. ex Hook. f. to a synonym of H. coerulescens. Engler (1912), still the only complete revision of Homalomena to date, generally also follows those of Hooker (1893) and Ridley (1907) in listing H. coerulescens including H. major, H, minor, and H. wallichii as synonyms. Ridley (1925) continued the trend of ignoring H. wallichii. Lastly there is Furtado's (1939) hopelessly muddled treatment of Javan H. rubra Hassk. (=H. pendula (Blume) Schott), a species absent from the Peninsula, but into which Furtado subsumed five Peninsular taxa: H. curoata Engl., H. major, H. minor, H. pontederiifolia, and H. wallichii. One can only speculate as to how such a distinctive species could have been so treated. The habit of the sterile plant - with proportionately long-petiolate pendent leaf blades (leaf tip directed somewhat downwards) recalls that of an Alocasia - while fertile plants are unmistakable by the exceptionally long peduncle, with the inflorescence often equaling the preceding petiole. The spathe color is also highly distinctive; dorsally the spathes are rich ochre yellow with a reddish brown median band and a green rostrum, while ventrally and internally they are pale yellow, externally with faint darker longitudinal veining. At anthesis they produce a powerful menthol-like smell reminiscent of Eugenia (Myrtaceae). The persistent fruiting spathes are also striking, turning to glossy reddish brown.
Homalomena wallichii is very uncommon in the wild, and furthermore appears to be restricted to a very small area of Pinang, fortunately within the Taman Negara Pulau Pinang ("Muka Head N.P.")