SYNGONIUM GENTRYANUM

PROTOLOGUE: Syngonium gentryanum , published in Annals of the Missouri Botanical Garden 68: 612 (1982).

Syngonium gentryanum Croat, sp. nov. Caudex ca. 2 cm diam.; lamina trisecta; petiolus ad 63 cm longus; vagina 16–28 cm longa, lamina media oblonga-elliptica, 27 cm longa, 9.3 cm lata; lobi laterales lobum medium aequantes, inaequalateres haud auriculatos. Inflorescentia 2 in axilla; pedunculus 7 cm longus; spathae tubus oblongus-ellipticus, 2.5–3.5 cm longus, 1.1–2.3 cm diam.; spathae lamina elliptica, acuminata; spadix ca. 8 cm longa, parte feminea spadicis 7 mm longa, 4 mm diam. Type: Peru, Huánuco, La Divisora, Tingo María–Pucallpa road near Loreto border, 1150–1250 m, premontane rain forest, Gentry, Daly & Cruz 18822 (MO-2415210, holotype; USM, isotype).

DISTRIBUTION: Peru: Peru.

DISTRIBUTION NOTE: Peru: Huánuco.

SPECIES DESCRIPTION:

Adult plants with stems ca. 2 cm diam.; petioles to 63 cm long, sheathed to 16–28 cm, slender, less than 1 cm diam., the sheath merging imperceptibly with the petiole at the apex; blades trisect, the lobes narrowly confluent at the base, the median lobe oblong-elliptic, acuminate at the apex, cuneate at the base, 27 cm long, 9.3 cm wide, drying pale yellowish brown, matte on the upper surface, slightly paler on the lower surface, the lateral lobes equal to the median lobe, 27–27.5 cm long, 7.5–8 cm wide, very inequilateral, the inner margin narrowly acute, almost paralleling the margin near the base, the outer margin attenuate and acute at the base, not at all auriculate, the lateral lobes markedly inequilateral, oblonglanceolate, acuminate at the apex, ca. 26 cm long and 8 cm wide, the inner edge narrowly acute at the base, narrowly confluent with the median lobe, the outer edge acute to obtuse, the midrib drying more or less flat on the upper surface, raised beneath; primary lateral veins 3–4 pairs; the tertiary veins weakly visible; the principal collective vein 3–6 mm from the margin.²

INFLORESCENCE:

Inflorescences 2 per axil, 10–11 cm long, slender; peduncles ca. 7 cm long, drying less than 4 mm diam.; spathe tube oblong-ellipsoid, 2.5–3.5 cm long (dried), 1.1–2.3 cm diam.; spathe blade, whitish, oblong-elliptic, narrowly acuminate at the apex; spadix to 8 cm or longer; pistillate portion of the spadix 7 mm long, 4 mm diam., the stigmas ovoid, 0.6–0.7 mm diam., slightly broader in the direction of the axis, contiguous; staminate portion of the spadix narrowly clavate, ca. 7.5 cm long or more, ca. 7 mm diam., the flowers irregularly 4–6-sided, 1–2 mm diam. (dried), the apex truncate, lacking a medial depression, shallowly incised along the sides between each stamen. Infructescences not seen.²

ECOLOGY:

The species is known only from the type locality in premontane rain forest in Huánuco Department, Peru. The type had a flowering inflorescence in March.²

ETYMOLOGY:

Named for Alwyn H. Gentry (1945–1993), the American botanist who collected the type on the road between Tingo María and Pucallpa in Huánuco Department, Peru, and whose neotropical collections supplied many of the aroids described in Croat's revisions.²

NOTES:

1. It is distinguished from other South American species by its trisect leaves with the lateral lobes not at all auriculate and equal to the median lobe in length.²

REFERENCES:

1. Plants of the World Online, Royal Botanic Gardens, Kew — Syngonium gentryanum

2. Annals of the Missouri Botanical Garden 68: 612 (1982) — protologue.