PHILODENDRON BIPINNATIFIDUM

PROTOLOGUE: Philodendron bipinnatifidum , published in Genera plantarum secundum ordines naturales disposita (Endlicher) 1: 237 (1837).

Philodendron bipinnatifidum Schott ex Endl.

Sphincterostigma Schott. Antherarum loculi angusti, elongati. Ovula in loculis subterna, diversa altitudine affixa. Stigma sessile, sphincteriforme, disco convexum, spongiolosum, annulo laevi, sulcato-crenato cinctum. — Spatha extus fusco-purpurea, intus alba. Sphincterostigma Schott l.c. Ph. bipinnatifidum Schott.

SYNONYMS:

HOMOTYPIC SYNONYMS: Thaumatophyllum bipinnatifidum (Schott ex Endl.) Sakur., Calazans & Mayo

HETEROTYPIC SYNONYMS: Arum pinnatifidum Vell.; Philodendron pygmaeum Chodat & Vischer; Philodendron selloum K.Koch; Philodendron sellowii André; Sphincterostigma bipinnatifidum Schott

DISTRIBUTION: E. Bolivia to SE. & S. Brazil and NE. Argentina: Argentina Northeast, Bolivia, Brazil South, Brazil Southeast, Paraguay.

DISTRIBUTION NOTE: iNaturalist: Espírito Santo, Minas Gerais, Paraná, Rio Grande do Sul, Rio de Janeiro, Santa Catarina, São Paulo.

INFLORESCENCE:

Translated from protologue: Anther locules narrow, elongate. Ovules about three per locule, attached at different heights. Stigma sessile, sphincter-shaped, the disc convex and spongy, girdled by a smooth, grooved-crenate ring. Spathe brownish-purple outside, white within.

ETYMOLOGY:

Although the protologue does not explain the name, bipinnatifidum is a transparent Latin compound: bi- (“twice”) plus pinnatifidus (“pinnately cleft”), referring to the deeply, doubly incised, feather-lobed blade of this philodendron’s mature leaves.

NOTES:

1. Schott designated this species as the type of his section Sphincterostigma, one of four sections he recognized within Philodendron (the others being Euphilodendron, Calostigma and Meconostigma).

2. Plants sold as Philodendron selloum or Philodendron bipinnatifidum may instead be Philodendron mello-barretoanum or Philodendron lundii.⁶,⁷ Eduardo G. Gonçalves distinguished Philodendron bipinnatifidum by soft, readily detachable stem scales and a concave upper petiole; Philodendron mello-barretoanum by hard, not easily detachable scales and a concave upper petiole; and Philodendron lundii by lacking persistent scales and having a flattened upper petiole.⁷

3. Eduardo G. Gonçalves, who treated Philodendron mello-barretoanum and Philodendron lundii as species separate from Philodendron bipinnatifidum, wrote in 2001 that Philodendron bipinnatifidum in that narrower sense comes from southeastern South America, including Argentina, Paraguay, Uruguay, southern Brazil, and the Brazilian coast as far north as Rio de Janeiro.⁸ In 2002 he noted that it usually occurs in areas with occasional frosts.⁹

STORY:

STORY TITLE: A spadix that burns fuel like a hovering hummingbird

Studied under its old name, Philodendron selloum, the spadix of this species runs hot. Its sterile male flowers respire at rates that approach those of a hovering hummingbird or a flying sphinx moth, burning through fuel fast enough that oxygen levels between the florets measurably drop; the ratio of carbon dioxide produced to oxygen consumed points to lipid, not starch, as the fuel behind the heat.³

Its pollinator, the scarab Erioscelis emarginata, feeds selectively inside the floral chamber. Tested directly against Philodendron bipinnatifidum’s flowers, the beetle was shown to prefer the plant’s sterile male flowers over its fertile ones, a florivory pattern that matches its role as pollinator rather than undermining it.⁴

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Philodendron bipinnatifidum

2. Genera plantarum secundum ordines naturales disposita (Endlicher) 1: 237 (1837) — protologue.

3. Seymour RS, Barnhart MC, Bartholomew GA. 1984. Respiratory gas exchange during thermogenesis in Philodendron selloum Koch. Planta 161(3): 229–232

4. Maldonado MA, et al. 2015. The selective florivory of Erioscelis emarginata matches its role as a pollinator of Philodendron. Entomologia Experimentalis et Applicata 156(3): 290–300

5. iNaturalist: Philodendron bipinnatifidum

6. Aroid-L mailing list, Eduardo G. Gonçalves, December 6th, 2002

7. Aroid-L mailing list, Eduardo G. Gonçalves, May 8th, 2003

8. Aroid-L mailing list, Eduardo G. Gonçalves, December 14th, 2001

9. Aroid-L mailing list, Eduardo G. Gonçalves, October 11th, 2002

Additional photos from iNaturalist by Oswaldo Guimarães, Escuela 791, andre2de3meijer and Wagner Nogueira