PHILODENDRON ATABAPOENSE
PROTOLOGUE: Philodendron atabapoense , published in Acta Botanica Venezuelica 10: 291 (1975). The protologue is reproduced below.
DISTRIBUTION: Venezuela (Amazonas): Venezuela.
SPECIES DESCRIPTION:
Translated from protologue: Long-climbing herb. Stem soon grayish light brown, 2.3 cm in diameter, the internodes slightly longer than thick. Cataphyll greenish, ivory toward the margin, sparsely wine-spotted, two-keeled on the back, deciduous. Petiole firm and rigid, slightly shorter than the blade, 47–59 cm long and 1 cm thick, terete or slightly convex ventrally above, pale green, wine-spotted above, and in the upper 4.3–5 cm rose-wine and slightly rough, sheathing in the lower 2.5–6(–12) cm. Leaf blade chartaceous, firm but fragile, to 50–63 cm long and (20.5–)23–30 cm wide, triangular-ovate in outline, widest 2–5 cm above the base of the midrib, from there upward for 15 cm of its length quickly narrowed with concave margins, then slightly narrowed with convex margins to the apex, which is usually obtuse with an acumen; downward from the widest point to the middle of the posterior lobe scarcely narrowed; posterior lobes more or less oblong, rounded to slightly angular at the obtuse apex, at midlength one 6.7–8.3 cm and the other 10.3–12 cm wide, separated by a mitriform sinus 15–18 cm long, with about 3 principal veins toward the base joined into posterior ribs that are naked in the sinus for 2.5–4(–5) cm; anterior lobe with sulcate primary lateral veins, (4–)5–6 on each side, spreading at 70°–85°; margin slightly undulate and edged with yellowish rose (0.1 cm); adaxially dark green and glaucescent, later somewhat glossy, the midrib flat, convex toward the base, 0.6 cm wide, yellowish green and wine-spotted, the posterior ribs flat and yellowish green; abaxially at first wine-colored with green venation, later green throughout and scarcely glossy, the midrib convex and sparsely wine-spotted, the primary veins prominent, the minor veins subparallel.
INFLORESCENCE:
Translated from protologue: Peduncles two together, 10.5–14 cm long, green, purple-spotted toward the apex. Spathe to 16.7 cm long, the tube elongate-fusiform, 8.7 cm long and 2.1 cm thick, green outside with a rose-wine margin (3–4 mm), intensely cherry-red inside, the blade whitish. Spadix sessile, strongly oblique at the base, 14.5 cm long; pistillate part 4 cm long and 1.3 cm thick; sterile staminate part 3.5 cm long and 1.5 cm thick, fertile part 8 cm long and 1.15 cm thick. Pistillate flowers more or less ovoid-urceolate, the ovary 8(–9)-locular, the locules 4-ovulate.
ECOLOGY:
Found as a climber near Yavita (Río Temi) and along the Yavita–Pimichín road, Amazonas, at 125–140 m; juvenile plants are frequent over sandy soil in disturbed areas of the forest near San Carlos de Río Negro.
ETYMOLOGY:
Formed from Atabapo, the name of a river and region in Amazonas state, Venezuela, plus the Latin suffix-ense, “belonging to a place.” Although the original description does not explicitly explain the name, it likely refers to the Atabapo region, in the general area of the type collection near Yavita.
NOTES:
1. Philodendron atabapoense can be confused with Philodendron acutatum, but it has thinner leaf blades that are proportionately longer and narrower and violet-purple on the lower surface when young.
2. Juvenile plants have conspicuously violet-purple blades.
3. Type locality: Venezuela, Amazonas, around Yavita (Río Temi) and along the Yavita–Pimichín road to km 5 toward Pimichín, 125–140 m.
4. In a reply on the Aroid-L mailing list on February 4th, 2005, Eduardo G. Gonçalves, who had collected Philodendron atabapoense in the field, described it as a widespread species of northern South America, occurring from Venezuela to Amapá state on Brazil's northern coast.⁵ On September 12th, 2006, he gave its range as Venezuela and Brazil.⁶ Plants of the World Online lists Venezuela (Amazonas) only.¹
5. According to Eduardo G. Gonçalves, writing on the Aroid-L mailing list on July 12th, 2001, the name Philodendron 'Santa Leopoldina' is not formally recognized and is used for at least three different plants, one of them Philodendron spiritus-sancti. He cautioned that a seedling of Philodendron atabapoense, which has somewhat elongated leaves that are reddish below, could be sold under that name, and warned against paying $300 for it.⁷
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Philodendron atabapoense
2. Acta Botanica Venezuelica 10: 291 (1975) — protologue.
3. iNaturalist: Philodendron atabapoense
4. Croat, T.B. & Lambert, N. 1986. The Araceae of Venezuela. Aroideana 9: 3–213
5. Aroid-L mailing list, Eduardo G. Gonçalves, February 4th, 2005
6. Aroid-L mailing list, Eduardo G. Gonçalves, September 12th, 2006
7. Aroid-L mailing list, Eduardo G. Gonçalves, July 12th, 2001
Additional photos from iNaturalist by Maria Clara Gil, jairmaia, Arthur Gomes, Michael Wallitis, Matheus Soares and Adriano Amir Didonet