CYRTOSPERMA MACROTUM
PROTOLOGUE:
Cyrtosperma macrotum Becc. ex Engl., published in Bullettino della R. Società Toscana di Orticultura 4: 295 (1879), as "macrota".
Type: Beccari P.P. 619, West Papua, Andai (lectotype FI, chosen by Hay 1988). The protologue also cited Beccari's Batanta plant, which Hay made the holotype of C. beccarianum, and a D'Albertis gathering from the Fly River that mixes a leaf of this species with an inflorescence of Lasia spinosa.⁴ Beccari redescribed the plant in Malesia in 1882 with figures of the flower, tepals, pistil, fruit and seed.⁵ ⚠ The 1879 Bullettino page itself is not on BHL or Internet Archive and has not been seen for this page.
SYNONYMS:
HOMOTYPIC SYNONYMS: N/A
HETEROTYPIC SYNONYMS: Cyrtosperma syapense Alderw., Bull. Jard. Bot. Buitenzorg sér. 3, 1: 374 (1920) (type a Bogor plant from Mount Syap, BO); Cyrtosperma subulispathum Alderw., l.c. 375 (type Versteeg 1108, Lorentz River, L); Cyrtosperma hastatum Alderw., l.c. 375 and Cyrtosperma consobrinum Alderw., l.c. 375, both placed here tentatively by Hay on their descriptions; Cyrtosperma janowskyi K.Krause, Nova Guinea 14: 216 (1924) (type Janowsky 489, Kurudu Island, L)
ACCEPTED INFRASPECIFICS: N/A
DISTRIBUTION:
New Guinea: New Guinea.¹
DISTRIBUTION NOTE: New Guinea with the Aru Islands and the d'Entrecasteaux group (Normanby and Fergusson), in three disjunct areas: Morobe and Madang Provinces; Milne Bay Province; and the southern side and western tip of Indonesian New Guinea together with Western Province, Papua New Guinea.⁴ Herbarium records run from 7 to 1,100 m, most below 200 m.⁶
SPECIES DESCRIPTION:
Moderately robust herb to 1.3 m tall; rhizome plagiotropic or very short, to 6 cm in diameter. Leaves 3 to several, hastate to sagittate; petioles divergent from the base, prickly, mottled or not; blades to c. 90 cm long and c. 50 cm wide, usually less, held horizontally or with the posterior lobes down, more or less coriaceous, armed beneath, sometimes heavily, and sometimes on the margins, often with all the blades facing the same way; primary and secondary venation, sometimes very, prominent beneath; costae of the anterior lobe curvinerved to pinnately arranged; posterior lobes markedly exceeding the anterior, asymmetrically ovate to broadly lanceolate, naked in the sinus for up to c. 5 cm.⁴
INFLORESCENCE:
Inflorescence solitary, occasionally two in succession, on peduncles similar to and slightly exceeding the petioles. Spathe narrowly lanceolate, to c. 15 cm long and 3 cm wide when flattened, occasionally spiny at the base and along the midline outside, white to yellowish green, brown or purple, its insertion shallowly cup-like or with the margins deflected or shortly decurrent on the peduncle; spadix c. 6–12 cm long and c. 5 mm wide in flower, pale yellow to green, free-stipitate, adnate-stipitate or sessile. Flowers hexamerous or tetramerous or mixed, then sometimes with some pentamerous; ovule solitary, more or less basal; anthers not exserted from the tepals at male anthesis. Fruit sessile, ovoid, orange; seed with a smooth testa, campylotropous, asymmetrical in side view.⁴ The spadix turns to the horizontal as the fruit develops.⁴
ECOLOGY:
Lowland swamp forest, lowland rainforest and lower montane forest; 7–1,100 m, mostly below 200 m.⁴,⁶
DISTRIBUTION MAPS:
Hay 1988 Fig. 11.
ETYMOLOGY:
From the Greek makros, long, and ous, otos, ear: the long posterior lobes of the leaf, the "ears" of a sagittate blade. Beccari's name was published as macrota.
NOTES:
1. Highly variable, with complex patterns. Morobe and Madang plants have coriaceous leaves, free-stipitate spadices, hexamerous flowers and a cup-like spathe base; Milne Bay plants have more membranous leaves, spadices with the stipe adnate to the spathe, at least some tetramerous flowers and a spathe shortly decurrent on the peduncle. In the western and southern populations these characters vary independently, so Hay declined to recognize the two eastern entities formally and suggested they are relics of a once continuous lowland species fragmented by Pleistocene drying.⁴
2. The name has a tangled history. Engler published it from Beccari's manuscript in a Florentine horticultural bulletin; Beccari's Batanta plant, cited with it, proved to be a different species; and Alderwerelt's C. hastatum was described with confused citations of von Römer's numbers that Hay could not reconcile.⁴
3. Alderwerelt's C. syapense, described from a young Bogor plant that flowered and fruited in January 1919, had a petiole 25–50 cm long, copiously but not densely prickly and dark green with irregular transverse streaks below, a spathe 10–12 by 3–3.5 cm, pale dirty yellow inside with pale green veins, a yellowish spadix 5–7.5 cm long, tetramerous flowers, and obovoid berries red below and green above.⁷
4. Cyrtosperma prasinispathum was separated from this species in 2024 on its unarmed leaf underside, oblanceolate posterior lobes, elliptic anterior lobe, deflected spathe with an entire margin, leek-green spathe and consistently tetramerous flowers; the two share the Bird's Head region.⁸
5. Type material of C. subulispathum (Versteeg 1108) is imaged at Kew and of C. janowskyi (Janowsky 489) at Leiden.⁶
STORY:
STORY TITLE: Where four species went to become one
Between 1920 and 1924, Alderwerelt van Rosenburgh and Krause added five New Guinea names to Cyrtosperma. In 1988 Hay looked at the material and sank four of them into Cyrtosperma macrotum.
What was left is genuinely, awkwardly variable. Flowers hexamerous, pentamerous, tetramerous or mixed, on one species. It absorbed a generation of over-description and stayed standing.
Its spadix turns to horizontal as it fruits, rather than swinging to point down as Cyrtosperma cuspidispathum does. And in 2024 Hariri and colleagues were still using it as the yardstick: the thing any new small, pale-spathed species has to be measured against before it can be called new.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Cyrtosperma macrotum.
2. Engler, A. in Beccari, O. 1879. Bullettino della R. Società Toscana di Orticultura 4: 295 — protologue.
3. iNaturalist: Cyrtosperma macrotum
4. Hay, A. 1988. Cyrtosperma (Araceae) and its Old World allies. Blumea 33: 427–469
5. Beccari, O. 1882. Malesia 1: 279–280, Tav. XXIV; 303
6. GBIF occurrence download for Cyrtosperma, 2026-09-05 (167 records)
9. Engler, A. 1910. Araceae. Nova Guinea 8(1): 249
10. Engler, A. 1911. Araceae-Lasioideae. Das Pflanzenreich IV.23C: 22
Additional photos from iNaturalist by Ezra Tetelepta, Shawn O'Donnell, bernhardlettneraustria, dougnaturalist, Hakim and Refer Iqbal