SYNGONIUM GLAUCOPETIOLATUM
PROTOLOGUE: Syngonium glaucopetiolatum , published in Annals of the Missouri Botanical Garden 68: 613 (1982).
Syngonium glaucopetiolatum Croat, sp. nov. Caudex haud glaucus, scandens, internodiis 2.5 cm diam.; foliorum petiolus 25–30 cm longus, ad ⅔ longitudinis usque vaginatus; petiolus juvenalis valde glaucus; lamina trisecta; segmentum medium 15–25 cm longum, 11–15 cm latum, ellipticum apice acuminatum; segmenta lateralia 16–24 cm longa, 10–12 cm lata, basi valde inaequalatera, valde auriculata, lateribus exterioribus lateribus, interioribus cuneatis. Inflorescentiae binatae; pedunculus 15 cm longus, valde glaucus; spathae tubus 6–7 cm longus, 5 cm latus, ovatus-ellipticus, valde glaucus. Type: Panama, Chiriquí, E of Boquete along steep forested slopes on Cerro Azul near Quebrada Jaramillo, 1620–1700 m, Croat 26821 (MO-2272459, holotype).
DISTRIBUTION: Panama: Panama.
DISTRIBUTION NOTE: Panama: Chiriquí, Panamá Province.
SPECIES DESCRIPTION:
Nomadic vine; juvenile plants with stems ca. 5 mm diam., epidermis drying brown, peeling; petioles 9–13 cm long, D-shaped above sheath, becoming sharply angular on pre-adult and adult plants; blades ovate-triangular, narrowly acute at apex, mucronate, sagittate at base, 13 cm long, ca. 5 cm wide at middle, posterior lobes 5.0–5.5 cm long, posterior lobes soon pinched off and directed outward at 45°, noticeably auriculate at the base; intermediate blades with lateral segments confluent with medial lobes. Adult plants with stems to 2.5 cm diam. (fresh), shrinking to 1.5 cm diam., epidermis green, shiny, drying yellowish brown with sharp longitudinal wrinkles; internodes 2–4 cm long. Leaves moderately thin, clustered in upper 30 cm of stem; petioles 25–30 cm long, sheathed ca. 2/3 their length, sheath 4.0–5.5 cm wide when flattened, free-ending and bluntly acute at apex, the upper part of the petiole subterete with a blunt medial rib; blades trisect, at least sometimes confluent to almost free; median leaflet elliptic, 15–25 cm long, 11–15 cm wide, acuminate at apex, briefly attenuate at base; lateral leaflets strongly inequilateral, 16–24 cm long, 10–12 cm wide, base prominently hastate on outer margin (the lobe usually moderately pointed), cuneate on inner margin, midrib bluntly depressed above, prominently raised beneath, primary lateral veins and the principle collective vein weakly sunken above, raised beneath, tertiary veins clearly visible (on dried specimens); primary lateral veins 6–8 per side, mostly departing midrib at ca. 40°; collective vein ca. 12–18 mm from the margin (midway to the apex).³
INFLORESCENCE:
Inflorescences 2 per axil; not seen in flower. Infructescences pendent; peduncle to 15 cm long; peduncle and spathe tube pruinose; spathe tube ovoid-ellipsoid, 6–7 cm long, ca. 5 cm diam. (fresh); spathe blade (dried) brown, subcoriaceous, ca. 10 cm long, acuminate at the apex, sometimes persisting in its dried condition. The species presumably flowers early in the rainy season, perhaps in June, because immature fruits have been seen in August and fruits of mature size have been seen in February.³
ECOLOGY:
Syngonium glaucopetiolatum is endemic to Panama in Lower montane wet forest at elevations of 1300–1800 m.³ altitude: 1300–1800 m
ETYMOLOGY:
From Latin glaucus, "bluish-gray," and petiolatus, "with a petiole," referring to the strongly glaucous petioles, which also give the peduncle and spathe tube a whitish bloom.²
NOTES:
1. The species is a member of sect. Syngonium and is distinguished by its large 3-lobed blades with markedly hastate lateral lobes, broad petiole sheath and by its glaucous young petioles, peduncles, and spathe tubes. Syngonium glaucophyllum has been confused with Syngonium hoffmannii. Grayum (2003) synonymized it with Syngonium hoffmannii in his treatment of the Araceae of Costa Rica but Syngonium glaucopetiolatum differs from Syngonium hoffmannii by having larger leaf blades (31–43 cm wide) which have prominent hastate and mostly pointed lobes with the medial and lateral lobes clearly confluent, the lateral lobes are proportionally shorter with the length to width ratio (tip of petiolule to tip of lobe divided but the lobe width midway) of 1.1–2.2 whereas for Syngonium hoffmannii the same ratio is usually 3.3–4.2 times longer than broad. In contrast to Syngonium glaucopetiolatum the leaf blades of Syngonium hoffmannii are smaller, rarely to 30 cm wide and have the lateral lobes with narrow, often pinched off auricales. In addition, the petioles of Syngonium glaucopetiolatum are very broad in the lower ½ and prominently glaucous whereas the petioles of Syngonium hoffmannii have narrow sheaths and are not glaucous. The blade shape of Syngonium glaucopetiolatum approaches that of Syngonium mauroanum but that species has been found to range no higher than 450 m and is apparently restricted to Premontane moist forest life zones.³
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Syngonium glaucopetiolatum
2. Annals of the Missouri Botanical Garden 68: 613 (1982) — protologue.