Arecaceae

Heterospathe Scheff.

First published in Ann. Jard. Bot. Buitenzorg 1: 141 (1876)
This genus is accepted
The native range of this genus is Philippines to W. Pacific.

Descriptions

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution
Around 40 species in Philippines to Moluccas, through Papuasia to Fiji, 20 species distributed in New Guinea.
Morphology General Habit
Moderate to quite robust single- and multi-stemmed tree palm, height to 10 m, some species stemless, stem diameter 3–7.5 cm, crownshaft absent (exceptionally present), monoecious
Morphology Leaves
Leaf pinnate, 90–330 cm long, 7–18 in crown, ±straight
Morphology Leaves Leaf sheaths
Sheath splitting to the base opposite the petiole, fibrous at the margins, 20–55 cm long
Morphology Leaves Petiole
Petiole 20–150 cm long. Leaflets 9–56 each side of leaf rachis, to 80 cm long, with pointed tips, arranged regularly (rarely somewhat irregularly), horizontal-Inflorescence between or below the leaves, branched 1–3 (possibly 4) orders, 46–130 cm long, branches widely spreading
Morphology Reproductive morphology Inflorescences Peduncles
Peduncle as long as to much longer than the inflorescence rachis, 30–110 cm Peduncular bract larger than and projecting from the prophyll, peduncular bract alone enclosing inflorescence in late bud, splitting, but usually remaining attached as inflorescence expands
Morphology Reproductive morphology Inflorescences
Rachillae slender and straight or curving
Morphology Reproductive morphology Flowers
Flowers in triads throughout the length of the rachilla, not developing in pits
Morphology Reproductive morphology Fruits
Fruit orange to red, globose to ellipsoid, 1–2.2 cm × 0.5–1.2 cm, stigmatic remains apical to lateral, flesh thin, endocarp thin, closely adhering to seed
Morphology Reproductive morphology Seeds
Seed 1, ellipsoid to globose, endosperm ruminate.
Ecology
Heterospathe is mainly found in submontane and montane forest up to 2300 m, but occurs less frequently in the lowlands.
Recognition
Heterospathe species are varied under- and mid-storey palms, some stemless, usually with fibrous leaf sheaths and almost always lacking a crownshaft. Their inflorescences appear between the leaves, but may later be presented below the leaves, and are branched 1 to 3 orders. Importantly, the first peduncular bract is much longer than and projects from the prophyll. Heterospathe is most easily confused with Dransfieldia, which is a very slender palm that always has a crownshaft, or Rhopaloblaste, which is crownshafted, displays dark hairs on the leaf rachis, and has an inflorescence with a short peduncle and caducous primary inflorescence bracts.
[TONG]

Vernacular
Sagisi palm.
Distribution
About 40 species from the Philippines and Micronesia to eastern Indonesia and to the Solomon Islands, Fiji and Vanuatu, including 16 species in New Guinea.
General Description
Dwarf to moderate, solitary or sometimes clustered, unarmed, pleonanthic monoecious palms. Stem creeping or erect, sometimes basally expanded, grey-green to brown, leaf scars prominent. Leaves pinnate, rarely entire bifid, erect, becoming spreading, often reddish when young; sheath splitting abaxially and not forming a well-defined crownshaft, margins fibrous, acute, glaucous or not; petiole short to elongate, usually deeply channelled adaxially, rounded abaxially, variously indumentose; rachis straight or curved, basally channelled adaxially, distally ridged, rounded abaxially, variously indumentose; leaflets, when present, single-fold, acute to acuminate, prominent, midrib elevated, marginal ribs often thickened, veins adaxially ± waxy or glabrous, abaxially tomentose or brown-dotted, with or without basifixed ramenta on midrib. Inflorescences interfoliar or infrafoliar at anthesis, branched to 1–4 orders basally, fewer distally, often with reddish-brown, deciduous tomentum; peduncle prominent, elongate, elliptic in cross-section; prophyll persistent, attached near the base and completely encircling the peduncle, tubular, 2-keeled laterally, more-or-less dorsiventrally flattened, splitting abaxially, and apically; peduncular bract 1 or rarely 2 (Heterospathe trispatha), attached below or sometimes above the middle of the peduncle, terete, beaked, enclosing the inflorescence in bud, greatly exceeding the prophyll, splitting abaxially and caducous or marcescent as the inflorescence matures; rachis short to elongate, bearing spirally arranged, short, pointed bracts subtending a few simple rachillae, or several branches with basal bare portions; rachillae slender, bearing sessile or slightly depressed, spirally arranged triads subtended by spreading lip-like bracts throughout the rachillae, or with paired or solitary staminate flowers toward the apex of the rachillae; bracteoles of the staminate flowers small, bracteoles surrounding the pistillate flower 2, spreading to cupular and imbricate. Staminate flowers symmetrical or slightly to markedly asymmetrical; sepals 3, distinct, broadly imbricate and rounded, ± keeled dorsally and gibbous basally; petals 3, distinct, valvate, usually about twice as long as the sepals, prominently lined when dry, ± acute, one usually somewhat larger than the others; stamens 6–36 or more, distinct, the filaments awl-shaped and strongly inflexed at the apex, anthers oblong in outline, dorsifixed and versatile at anthesis, latrorse; pistillode either small and conical, or columnar, prominent, nearly as long as the stamens, sometimes with an expanded apex. Pollen ellipsoidal asymmetric, occasionally oblate triangular; aperture a distal sulcus, infrequently a trichotomosulcus; ectexine tectate, perforate, perforate and micro-channelled or finely perforate-rugulate, aperture margin similar or slightly finer; infratectum columellate; longest axis ranging from 26–54 µm [12/32]. Pistillate flowers symmetrical, ± same size as the staminate; sepals 3, distinct, broadly imbricate, rounded; petals 3, distinct, broadly imbricate with briefly valvate apices; staminodes 3, tooth-like; gynoecium unilocular, uniovulate, short, soft, expanded upward into a thick stylar region below 3 recurved, short stigmas, the ovule lateral at top of locule, pendulous, hemianatropous. Fruit globose to ellipsoidal, small to large, orange to red when mature, stigmatic remains apical, eccentrically apical or subapical to lateral; epicarp smooth but drying granular or with irregular lines over short sclerosomes in the thinly to thickly fleshy mesocarp, with flattened anastomosing fibres, endocarp thin, operculate, smooth, shining within, or with thickened adnate fibres, irregularly sculptured, ridged and grooved, beaked at the apex, with a mass of slender fibres within a framework of thickened fibres at the base. Seed not adherent to endocarp, globose to ellipsoidal or with angled and with 3 rounded ridges laterally and abaxially, attached apically and laterally by the elongate hilum extending nearly the length of the seed, raphe branches simple to anastomosing, endosperm ruminate or rarely homogeneous (H. longipes and H. uniformis); embryo basal. Germination adjacent-ligular; eophyll bifid where known. Cytology: 2n = 32.
Morphology
Leaf (Heterospathe elata; Tomlinson 1961), root (Seubert 1998a, 1998b) and fruit (Essig et al. 1999).
Diagnostic
Very variable small to moderate, solitary or clustered pinnate-leaved palms of the Philippines, the Moluccas, New Guniea and western Pacific Islands; lacking a conspicuous crownshaft, and fruit with lateral to apical stigmatic remains.
Biology
Inhabitants of lowland and montane rain forest. Many species are undergrowth palms; a few contribute to the forest canopy.
[PW]

Uses

Use
Fruit of Heterospathe elata is chewed as a betel substitute in the Philippines; the cabbage is said to be edible and the split petioles and leaflets are used in weaving.
[PW]

Sources

  • Herbarium Catalogue Specimens

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Palmweb - Palms of the World Online

    • Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet http://www.palmweb.org. Accessed on 21/04/2013
    • Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License http://creativecommons.org/licenses/by-nc-sa/3.0

  • Trees of New Guinea

    • Trees of New Guinea
    • http://creativecommons.org/licenses/by-nc-sa/3.0