PHILODENDRON CARINATUM

PROTOLOGUE: Philodendron carinatum , published in Kew Bulletin 60: 129 (2005). The protologue is reproduced below.

DISTRIBUTION: Brazil (Amapá, NE. Pará): Brazil North.

SPECIES DESCRIPTION:

Scandent herb. Stem laterally flattened, strongly attached to the host tree, internodes 0.6–1.4 × 1.2–2.4 cm, grayish, intravaginal squamules deciduous, small. Leaves numerous (10–12) per plant; prophylls deciduous, 10.5–14 × 2.5–4 cm without visible nectaries, strongly 2-keeled, keels wavy; petioles 6–9 cm long, 1.4–2 cm diam. at apex, green with an apical red ring, strongly flattened dorsiventrally, margins strongly keeled laterally, upper quarter of the keel strongly wavy; leaf blade obovate, 28.5–32 × 10.5–12.5 cm, dark semiglossy green above, light semiglossy green below; drying brown, primary lateral nerves 7–8 per side, arising at an angle of 50–60°, slightly discolorous and impressed adaxially, paler than the leaf blade, concolorous and slightly prominent abaxially; apex acuminate, base obtuse to rounded.

INFLORESCENCE:

Inflorescences 2–3 per floral sympodium; peduncle 6–7 × 0.7–0.9 cm; spathe 8–9 cm long, moderately constricted at anthesis, tube 4.5–5 cm long, 2.3–2.5 cm in diameter, green outside, white inside with delicate reddish stripes, producing resinous droplets at anthesis, lamina 4.5 × 3–3.5 cm at anthesis, green outside, white inside, apex shortly acuminate; spadix 7.5–8.5 cm long, fertile male portion 4.3–4.5 × 0.6–0.7 cm, producing occasional droplets of resin, obtuse at apex with 3–4 rows of sterile flowers, sterile male portion 0.6–0.7 × 1.0–1.1 cm, thicker than the fertile male portion, female portion 2.8–3.0 × 0.8–1 cm, adnate to spathe for 30–40% of its length. Flowers: male flowers prismatic, 3–4-androus, 1–1.5 × 1–1.5 mm; staminodes subprismatic to obpyramidal, 2–2.5 × c. 1 mm, gynoecium prismatic, c. 2–2.5 mm long, stigma hemispherical, c. 1 mm diam., ovary 6–8 locular, locules 2–4-ovulate, placentation sub-basal, funicles as long as ovules. Infructescence unknown.

ECOLOGY:

Found only at the type locality at Porto Grande, Amapá state, northern Brazil, where it seems to be rare. It was found as a low scandent plant, growing strongly attached to thin understory trees.

ETYMOLOGY:

From Latin carinatus, “keeled” (from carina, “keel”). Although the original description does not explicitly explain the name, it most likely refers to the strongly keeled petioles and prophylls, the first character given for recognizing the species.

NOTES:

1. Philodendron carinatum can be recognized by its strongly keeled petioles and prophylls, petioles with a reddish ring at apex and obovate leaves. Also distinctive are the short internodes and flattened stems that are strongly attached to the host trees.

2. The species belongs to Philodendron subgenus Philodendron section Calostigma (Schott) Pfeiffer.

3. It seems to be closely related to Philodendron wurdackii G. S. Bunting, from Venezuela, which also has keeled petioles with a purplish ring at the apex. However, Philodendron carinatum differs in having 3 ovules per locule, whereas the locules are uniovulate in Philodendron wurdackii. Moreover, Philodendron wurdackii has flowering internodes that are longer than broad and are only loosely attached to the host tree.

4. Another similar species is Philodendron angustialatum Engl., a poorly known species from Peru, which also differs from Philodendron carinatum in having uniovulate locules and long internodes. In fact, Philodendron wurdackii may well prove to be synonymous with Philodendron angustialatum.

5. It has proven to be easy to cultivate, although it grows very slowly in southeastern Brazil. Because of the compact growth and the beauty of the obovate leaves with their peculiar keeled petioles, it has potential as an ornamental plant.

6. The original description is not consistent on the number of ovules per locule: 2–3 in the Latin diagnosis, 2–4 in the English description and 3 in the comparison with Philodendron wurdackii.

REFERENCES:

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

2. Kew Bulletin 60: 129 (2005) — protologue.

3. iNaturalist: Philodendron carinatum

Additional photos from iNaturalist by jeremy grossman and Wagner Nogueira