PHILODENDRON ADAMANTINUM
PROTOLOGUE: Philodendron adamantinum , published in Synopsis Aroidearum Complectens Enumerationem Systematicam Generum et Specierum Huju Ordinis 114 (1856). The protologue is reproduced below.
SYNONYMS:
HOMOTYPIC SYNONYMS: Thaumatophyllum adamantinum (Mart. ex Schott) Sakur., Calazans & Mayo
DISTRIBUTION: Brazil (Minas Gerais): Brazil Southeast.
DISTRIBUTION NOTE: iNaturalist: Minas Gerais.
SPECIES DESCRIPTION:
Translated from protologue: Stem the thickness of a thumb, erect, nearly unbranched, marked with elliptical, transverse scars. Petiole 5–6 inches long, grooved with a rather flat channel on the front, convex on the back; leaf blade in outline roundly cordate-sagittate, pinnately parted, leathery, its segments broadly linear and obtuse, the lowest ones — those of the petiole’s basal lobes — broadly wedge-shaped and nearly three-parted, the uppermost (terminal) segment much shorter than the others, rounded, very shortly apiculate. All veins and veinlets whitish beneath.
ECOLOGY:
Found in crevices on exposed sandstone and quartzite outcrops in the Espinhaço Range, Minas Gerais, Brazil.
ETYMOLOGY:
From Latin adamantinus, “of adamant” (Greek adamas, “unconquerable,” the name later given to diamond). The protologue does not explain the epithet, but Martius collected the type at Tejuco, in the Serro Frio district — the Minas Gerais diamond region later renamed Diamantina — so it most likely honors that locality rather than describing the plant itself.
NOTES:
1. Type locality: Diamantina (historically Tejuco, in the Serro Frio district), Minas Gerais, Brazil; the holotype, Martius 1208, is held in Munich (M).
2. Molecular and morphological evidence (Sakuragui et al. 2018) segregated this species, with the rest of Philodendron subg. Meconostigma, into a new genus, as Thaumatophyllum adamantinum (Mart. ex Schott) Sakur., Calazans & Mayo. The transfer is not universally followed; World Flora Online still treats Philodendron adamantinum as the accepted name.
3. The species is endemic to the Espinhaço Range in Minas Gerais and relies on a single pollinator, the scarab beetle Erioscelis emarginata (Cyclocephalini), which is attracted to its thermogenic, strongly scented inflorescence.
STORY:
STORY TITLE: One beetle, one scent: how Philodendron adamantinum finds its pollinator
On the quartzite outcrops of the Espinhaço Range in Minas Gerais, Philodendron adamantinum depends on a single insect for its reproduction: the scarab beetle Erioscelis emarginata. At dusk the inflorescence heats itself close to 19°C above the surrounding air, reaching temperatures around 42°C, and releases a strong, sweet fragrance built mainly around one compound, dihydro-β-ionone. Pereira and colleagues, who set out scented decoys in the field, found that this single volatile, alone or paired with methyl jasmonate, was enough to draw the beetles in — a chemical signal precise enough that this scarab beetle is the plant’s sole path to pollination.⁴
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Philodendron adamantinum
2. Synopsis Aroidearum Complectens Enumerationem Systematicam Generum et Specierum Hujus Ordinis: 114 (1856) — protologue.
3. Sakuragui et al. 2018, PhytoKeys 98: 51–71
4. Pereira et al. 2014, Biological Journal of the Linnean Society 111: 679–691
5. Gonçalves-Souza et al. 2017, Annals of Botany 119: 533–543
6. iNaturalist: Philodendron adamantinum
Additional photos by David Scherberich