ALOCASIA HETEROPHYLLA
SYNONYMS: Alocasia manilensis, Alocasia warburgii, Caladium heterophyllum, Colocasia heterophylla
DISTRIBUTION: Philippines | Luzon, Mindanao, Polillo
CLIMATE: Tropical humid climate
Humidity is moderate throughout the year, ranging from 60% to 70%
Temperature is varies between the seasons - within the range of 48°F/9°C to 88°F/31°C during the day. Minimum temperatures never dip below 45°F/7°C
Rainy and humid season (October to May) and a dry season between June and October. The average annual rainfall is 1,200 mm
ECOLOGY: Lowland rain forest (dipterocarp forest) to ca. 300 m altitude.
SPECIES DESCRIPTION:
Small herb to ca. 40 cm tall; stem to ca. 20 cm long, decumbent to creeping, ca. 1.7 cm thick; leaves 3-5 together; petiole to ca. 35 cm long, sheathing in the lower ca. quarter to third; blade to ca. 27 cm long, narrowly (hasto-) sagittate, sometimes shallowly to deeply peltate in adult plants and then some non-peltate leaves also present; anterior lobe to 20 cm long, to ca. 10 cm wide at base, narrowly triangular, with the margin sometimes shallowly sinuate; anterior costa not very prominent abaxially, with 3-4 sometimes opposite primary lateral veins diverging at ca. 45-60° and usually distally deflected towards the leaf tip, then joining a conspicuous submarginal vein situated ca. 3 mm from the margin; secondary venation rather widely spaced (ca. 3 mm) arising from the primary at a high angle, thence mostly abruptly (ca. right angle) deflected towards the margin and forming rather disorganised interprimary collective veins; glands in the axils of primary veins inconspicuous; posterior lobes diverging at an acute angle, narrow, tapering, sometimes distally out-turned; posterior costae naked in sinus for ca. 1.2 cm to peltate for ca. 20% of their length
INFLORESCENCE:
Inflorescences paired, to 4 together; peduncle to ca. 4 cm diam., ca. half the length of the petioles: spathe 5-6.5 cm long; lower spathe narrowly ovoid, 2.5-3 cm long, differentiated from the limb by a rather long gradual constriction; limb narrowly lanceolate, eventually reflexed; spadix ca. three quarters of the length of the spathe, shortly stipitate, with the stipe adnate to the spathe: female zone 0.5-1 cm long, containing few to several flask-shaped pistils: style ca. 0.5 mm, stigma globose; sterile interstice ca. 5 mm long, comprised of massive synandrodia filling the upper part of the cavity of the lower spathe; male zone ca. 5-8 mm long, subcylindric, ca. 3 mm thick; synandria more or less hexagonal, ca. 1.2 mm diam., opening by apical pores not capped by synconnective; appendix ca. 2 cm long, tapering; infructescence ovoid, ca. 3 cm diam.
VARIEGATED FORMS: N/A
ETYMOLOGY: Given this species’ proclivity for high phenotypical variation, that is, high variability in how the plants appear, it was given the name heterophylla meaning different leaves. This is derived from the Greek héteros (ἕτερος), meaning ‘the other of two’ or ‘different’, and from the Greek phúllon (φύλλον) meaning “leaf”.
NOTES:
While Alocasia ‘Corazon’ is often mentioned as a cultivar of A. heterophylla, it is believed to be an undescribed Philippine species, based on inflorescence morphology
This species is distinguished from A. ramosii by the leaves sometimes peltate in mature plants, the gradually constricted spathe, the massive synandrodia of the sterile interstice, the more widely separated secondary venation, distally curved primary venation and the conspicuous submarginal vein situated well in from the margin. Compared to A. ramosii and A. boyceana, Alocasia heterophylla has the fewest lateral veins , ranging from three to four (sometimes five, but this isn't the norm). Counting the lateral veins (in red) does not include those at the posterior lobes but at the beginning of the petiole attachment. Also, the secondary veins of this species arch widely. See below, in white.
A distinguishing feature of A. heterophylla leaves are the very noticeable submarginal veins, which clears the leaf margins by about 3 mm.
Alocasia heterophylla usually has peltate, or shield-like leaves (petiole inserts near or on the center of the leaf). As you can see in the photos above and below both peltate and non-peltate heterophyllas can occur within the same population.
A. boyceana and A. ramosii only present with non-peltate leaves, or at most sub-peltate, making it an easy distinguishing factor for A. heterophylla
Historically A. heterophylla has been called many names and it wasn’t until recently that botanists collated them under the heterophylla species.
The type of A. manilensis consists of seedling leaves only, but it matches A. heterophylla in shape and in the characteristic submarginal vein.
The syntypes of A. warburgii no longer survive at Berlin presumably because Engler and Krause had reduced this to the synonymy of A. heterophylla and Krause consequently did not take out a representative specimen for protection from possible war damage which did, of course, subsequently occur. My acceptance of the placement of A. warburgii in the synonymy of A. heterophylla is based on the joint opinion of Engler and Merrill, who examined the pertinent material of both species together at Berlin, concluding that the two were indeed identical (Merrill's annotation on Haenke s.n. at PR - the holotype of A. heterophylla). Elmer's interpretation, however, also evidenced by specimen annotations, was different, applying the name A. warburgii to material of what is here recognised as a new species, A. boyceana. Elmer's identifications of Araceae were not always reliable and it is not apparent that he had examined the relevant types; I therefore defer to Engler and Merrill's view. The selected neotype of A. warburgii is a widely distributed fertile collection that falls well within the concept of A. heterophylla. The illustration of this species in Krause & Engler (loc. cit.) is of poor quality, and it is perhaps as a consequence of this that the name Alocasia heterophylla has been applied by various workers to material of distinctly different species in Java and Borneo, where this species does not occur. Almost all the material that Krause & Engler cited under A. heterophylla was destroyed, but one extant specimen, Merrill 5328, is not of this species. Together with the fact that the illustration of the spadix does not show the characteristic enlarged synandrodia, this suggests that the illustration is based on material of more than one species.
The cultivars Alocasia heterophylla ‘Blue Prince' and Alocasia heterophylla ‘Blue Lady' (Burnett, 1984: figs 17 & 18) appear to be derived from this species.
Other specimens seen: Luzon, Zambales Prov. Mt Pinatubo, Clemens 17362 (UC); Luzon, Pangasinan Prov., Labrador, Mt San Isidro, Fenix BS 29883 (US); Luzon, Quezon Prov., Quezon National Park, ca. 10 km W of Atimonan, Nicolson 800 (K, US); Luzon, Rizal Prov., Mt Susong Balaga, Ramos & Edano BS 29238 (US); Luzon, Rizal Prov., Mt Irig, Ramos & Alocasia in the Philippines 19 Edano BS 48444 (UC); Mindanao, Davao Prov., Mati, Ramos & Edaho BS 49310 (NY, UC); Polillo Island, Robinson BS 9199 (E, NSW); Oriental Mindoro, Mansalay, Mt Yagaw (E slope), Sulit & Conklin PNH 16954 (GH, L).
CULTIVARS: Alocasia heterophylla ‘Green’, Alocasia heterophylla ‘Green Veins’, Alocasia heterophylla ‘Silver’, Alocasia heterophylla ‘Silver Kris’
David Burnett’s ‘The Cultivated Alocasia’ also lists two additional cultivars, A. heterophylla ‘Blue Lady’ and A. heterophylla ‘Blue Prince’, though given the age and quality of the photos, it is not possible to distinguish them from existing cultivars
HYBRIDS: Alocasia ‘Mindanao’ (A. clypeolata x A. heterophylla)
