PHILODENDRON AUREIMARGINATUM
PROTOLOGUE: Philodendron aureimarginatum , published in Aroideana 27: 38 (2004).
Philodendron aureimarginatum Croat, sp. nov. Type: PERU. Dept. Loreto: Prov. Maynas, Dtto. Iquitos, Puerto Almendra, near Río Nanay, 3°48'S, 73°25'W, 122 m, 29 Nov. 1976, Juan Revilla 1972 (holotype, MO–2610359; isotypes, F, USM). Figures 1–3.
Planta hemiepiphytica; internodia adulta brevia, 5–8 cm longa, ad 3.5 cm diam.; cataphylla 15–17 cm longa, mox decidua; petiolus (9)15–24(36) cm longus, obtuse sulcatus; lamina anguste oblongo-ovata vel oblanceolato-elliptica, 54–75 cm longa, 12–27 cm lata; nervis primariis lateralibus 7–9 utroque; inflorescentia 1 in quoque axilla; pedunculus 2–6 (rarius ad 23) cm longus; spatha viridis vel alba, (10)12–14 cm longa, 2.5 cm diam.; spadix 11.5–13.5 cm longus; parte pistillata 3.5–4 cm longus; baccae aurantiacae vel rubrae.
DISTRIBUTION: SE. Colombia to N. Peru and Brazil (Acre): Brazil North, Colombia, Ecuador, Peru.
SPECIES DESCRIPTION:
Appressed-climbing hemiepiphyte; internodes 5–8 cm long, 1 cm diam. at lower nodes, 2–2.5 cm diam. near apex, drying yellow-brown, glossy, longitudinally folded, to 6 mm diam.; cataphylls 15–17 cm long, seemingly unribbed, persisting semi-intact at upper nodes on larger stems, drying dark brown, soon weathering to slender, reddish brown fibers, these also mostly deciduous. LEAVES with petioles (9)15–24(36) cm long, typically shorter than the blades, thicker than broad and obtusely sulcate adaxially, 0.5–1 mm diam.; blades narrowly oblong-ovate to weakly oblanceolate-elliptic, 54–75 cm long, 12–27 cm wide, broadest at or slightly above the middle, 2.7–4 times longer than wide, 1.1–2.6 times longer than petioles, abruptly acuminate at apex, narrowly acute to truncate to subcordate (rarely cordate) at base; upper surface drying grayish to grayish brown, with inconspicuous scattering of short, whitish, raphide cellular inclusions; lower surface drying dark yellowish brown, with inconspicuous areolate pattern of depressions; both surfaces drying matte, with a thickened, more or less hyaline, yellowish brown, submarginal band 1.5–2 mm wide, this thicker and more elevated on the lower surface; margins thin, revolute; sinus (when present) arcuate, to 7 cm deep; major veins drying blackened on lower surface; midrib flat on upper surface, thicker than broad on lower surface, drying acute; primary lateral veins 7–9 pairs, arising at a very acute angle then spreading at 30–45° angle to the margin; interprimary veins usually 1 between each pair of primary lateral veins and only slightly less prominent; basal veins 2–4(5) per side, free to base or nearly so, the uppermost arising at 10–20° angle, the lowermost spreading to as much as 90° angle or reflexed.
INFLORESCENCE:
INFLORESCENCES apparently 1 per axil; peduncles mostly 2–6 cm long, rarely to 23 cm long in fruit, drying 4–10 mm diam.; spathe green, sometimes white at anthesis, (10)12–14 cm long, to 2.5 cm diam. on tube; spadix 11.5–13.5 cm long; pistillate portion 3.5–4 cm long, drying 10–13 cm diam.; male portion 9.7 cm long; sterile male portion 6 mm long, 8–13 mm diam.; fertile male portion drying 7–12 mm diam., the constricted portion 6.5–10 mm diam.; ovaries (7)9–10(12)-locular; ovules ca. 5–6 per locule. INFRUCTESCENCE apparently 7 cm long, 3.5 cm diam.; berries bright orange to red, the persistent styles 1.2–1.6 mm diam., annular, with the margins paler and with distinct stylar depressions, conspicuously depressed and darker medially; seeds drying dark brown, 1 mm long, 0.4 mm diam.
ECOLOGY:
Found in areas of white sand soil, at less than 150 m elevation, in an area of tropical moist forest (bh-T).
ETYMOLOGY:
Although the original description does not explicitly explain the name, the epithet joins Latin aureus, “golden,” with marginatus, “margined,” and refers to the conspicuous, more or less hyaline, yellowish brown submarginal band along the leaf blade margins, singled out in the protologue as the species’ most distinctive feature.
NOTES:
1. Philodendron aureimarginatum is a member of Philodendron sect. Calostigma, subsect. Macrobelium. The species is characterized by its somewhat elongated blade, usually rounded to subcordate at the base, and especially by the conspicuous, more or less hyaline blade margins.
2. Philodendron aureimarginatum is most similar to Philodendron wittianum Engl., a species with similar blade shape. That species differs in having shorter internodes, cataphylls that usually persist on the stem and blades that lack hyaline margins.
3. The species almost certainly occurs also in Acre, based on Croat 85685 from near Cruziero do Sul, but the specimen has not been compared with other material because it has never been sent from Brazil. If it does indeed prove to be the same species, it is important to note that this collection had at least two inflorescences per axil.
4. Balslev 84636 is atypical in having a much more deeply cordate leaf base but otherwise, has the typical features of the species, including the unusual leaf margin.
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Philodendron aureimarginatum
2. Aroideana 27: 38 (2004) — protologue.