CYRTOSPERMA HAMBALII
PROTOLOGUE:
Cyrtosperma hambalii A.Dearden & A.Hay, published in Aroideana 24: 102–104 (2001), "A new species of Cyrtosperma (Araceae) from West Papua", with two photographs.
Type: A. Hay & A. Dearden s.n., 12 May 2001, cultivated at Redlynch, Cairns, Queensland, from a plant brought into the Freeport nursery at Timika from the vicinity of Timika, West Papua (original collection G.G. Hambali s.n.) (holotype NSW).²
Diagnosis, translated from the Latin: differs from C. beccarianum in the shorter petiole, the very long spathe and the exserted stamens; from C. cuspidispathum in the much smaller plant, the shorter petiole, the very small anterior lobe of the leaf, the wholly erect spathe, the much shorter spadix and the exserted stamens.²
From the protologue: Rhizomatous herb to c. 1 m tall. Stem condensed, subterranean. Leaves c. 4 bunched together; petiole erect, short, about half the length of the blade, c. 17 cm long, geniculate in the apical 1 cm, unarmed, dark olive brown at the base, mid green at the apex and olive green mottled olive brown between, sheathing in the lower third; blade sagittate, held with the posterior lobes erect and the anterior lobe pointing obliquely down, c. 32 cm long; anterior lobe much shorter than the posterior, narrowly triangular, 8 cm long and c. 2.5 cm wide where it meets the posterior lobes; posterior lobes rather narrowly elliptic, c. 23 by 7 cm, acuminate for 2 cm; costae very prominent beneath and impressed above, the anterior costa without primary veins and running sharply to the leaf tip, the posterior costae naked in the sinus for 5–8 mm with 5 or 6 primary lateral veins on each side diverging at c. 30°; finer venation a loose reticulum. Inflorescence solitary; peduncle much exceeding the petioles, 47 cm long, armed with scattered straight prickles, increasingly concentrated upwards, only in the distal 12 cm. Spathe erect, unarmed, with a prominent central ridge on the back, very long and slender, 53 cm long and 2.2 cm wide level with the spadix, then tapering, convolute at the base, the margins close together above, dark greenish brown with eight green vertical stripes outside and blackish within. Spadix much shorter than the spathe, cylindric, blunt, 6 by 0.8 cm, sessile; flowers hexamerous, c. 1.5 mm across; anthers exserted from the tepals at male anthesis. Fruit unknown.²
SYNONYMS:
HOMOTYPIC SYNONYMS: N/A
HETEROTYPIC SYNONYMS: N/A
ACCEPTED INFRASPECIFICS: N/A
DISTRIBUTION:
New Guinea: New Guinea (south-west).¹
DISTRIBUTION NOTE: Endemic to New Guinea and, in the protologue, known only from the vicinity of Timika in southern West Papua, now the Mimika Regency of Central Papua Province.² iNaturalist records come from the Mimika lowlands and from Sorong at the western tip of the Bird's Head;³ the Sorong plants long grown at Bogor under this name proved to be C. prasinispathum, so the Sorong records deserve a check.⁵ Living plants are grown at the Bogor Botanic Gardens.⁵
SPECIES DESCRIPTION:
A rhizomatous herb to about 1 m tall with a condensed underground stem and about four leaves bunched together. The petiole is unusually short, about half the length of the blade (c. 17 cm), unarmed, mottled olive, sheathing in its lower third and geniculate at the tip. The blade is sagittate, c. 32 cm long, and is held with the two narrowly elliptic posterior lobes (c. 23 by 7 cm) pointing up and the much reduced, narrowly triangular anterior lobe (8 by 2.5 cm) pointing obliquely down, which gives the plant its "rabbit's ears" look.² Plants near Timika have since been seen with ripe berries expelled from the florets and hanging on the spadix, the "anthuriocarp" otherwise known in the genus only in C. cuspidispathum.⁷
INFLORESCENCE:
Inflorescence solitary, held high above the leaves on a peduncle 47 cm long that is prickly only in its distal 12 cm. Spathe perfectly erect, very long and slender, 53 cm long and 2.2 cm wide at the level of the spadix, tapering above, convolute at the base, with a prominent central ridge on the back, dark greenish brown with eight green stripes outside and blackish inside. Spadix sessile, cylindric, blunt, only 6 by 0.8 cm; flowers hexamerous, c. 1.5 mm across, the anthers exserted from the tepals at male anthesis. Fruit unknown in 2001;² berries have since been seen on plants near Timika.⁷
ECOLOGY:
Habitat not recorded in the protologue;² the iNaturalist records are lowland, from the swampy coastal plain around Timika and from Sorong.³
DISTRIBUTION MAPS:
None published in the sources consulted.
ETYMOLOGY:
Named for Gregory G. Hambali, whose collecting in West Papua produced the species, in acknowledgment of his long and expert contribution to Indonesian botany and horticulture and of his part in the rediscovery of the closely related Lasia concinna.²
NOTES:
1. Closest to the rheophytic C. beccarianum in leaf shape, from which it differs in the short petioles, the extremely elongate dark greenish brown spathe (ovate, wide open and generally white in C. beccarianum), the hexamerous flowers (tetramerous there) and the exserted stamens (not exserted there). The very long spathe recalls C. cuspidispathum, a far larger plant whose spathe is reflexed to dangling in its distal part, whose stamens are not exserted, whose leaves have well-developed anterior lobes with the posterior lobes held down, and whose petioles carry upturned prickles. In spathe color and exserted stamens it recalls C. carrii of Central Province, which has extremely prickly leaves with well-developed anterior lobes and a squat, open spathe.²
2. The authors correct Hay's 1988 statement that the stamens of C. carrii are not exserted: it rested on limited herbarium material, and living plants show them exserted.²,⁶
3. The sheath reaching a third of the way up the petiole is unusual in the genus, though it may simply be that the rest of the petiole is foreshortened. The species keys out in Hay's 1988 key at a new couplet 3a, leaf blade with the anterior lobe much reduced and narrowly triangular and the posterior lobes erect; the genus then stood at twelve species.²,⁶
4. Hariri et al. (2024) compare their new C. prasinispathum with the Bogor plants that had carried this name and figure a leaf of C. hambalii beside it (their Fig. 1J).⁵
5. Six wild observations on iNaturalist, four of them research grade, are the best photographs of the species available to the build; the protologue's two figures show the flowering plant and the inflorescence.²,³
STORY:
STORY TITLE: The first crack in a closed genus
Hay's 1988 monograph read like a finished job: eleven species, keyed, mapped, illustrated, with the excluded names swept out to other genera. Thirteen years later Dearden and Hay described a twelfth from Indonesian New Guinea. Three more have followed since, and the count now stands at fifteen.
Hambali's species also turned out to do the trick that had been the property of Cyrtosperma cuspidispathum alone. Imran watched plants near Timika push their ripe fruits out of the spadix to hang by the stripped skin of the tepals, and it went into the 2020 paper as a note added in proof.
GBIF holds exactly one record of the species: somebody's observation, made in 2025.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Cyrtosperma hambalii.
2. Dearden, A. & Hay, A. 2001. A new species of Cyrtosperma (Araceae) from West Papua. Aroideana 24: 102–104 — protologue.
3. iNaturalist: Cyrtosperma hambalii
4. GBIF occurrence download for Cyrtosperma, 2026-09-05 (1 record)
6. Hay, A. 1988. Cyrtosperma (Araceae) and its Old World allies. Blumea 33: 427–469
7. Hay, A. & Imran. 2020. Cyrtosperma giganteum Engl. (Araceae–Lasioideae) found again in Papua Province, Indonesia. Aroideana 43(3–4): 4–11 (note added in proof).
Additional photos from iNaturalist by Hakim, Yanuar Ishaq Dc, Dwi Suratman and Refer Iqbal