International Aroid Society

20. Syngonium glaucopetiolatum Croat, sp. nov. TYPE: Panama, Chiriqui, E of Boquete along steep forested slopes on Cerro Azul near Quebrada Jaramillo, 1620-1700 m, Croat 26821 (MO-2272459, holotype).

Caudex haud glaucus, scandens, internodiis 2.5 cm diam.; foliorum petiolus 25-30 cm longus, ad 2/3 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.

Hemiepiphytic creeper. Juvenile plants with stems ca. 5 mm diam., the epidermis drying brown, peeling; petioles 9-13 cm long, D-shaped above the sheath, becoming sharply angular on pre-adult and adult plants; blades ovate-triangular, narrowly acute at the apex, mucronate, sagittate at the base, 13 cm long, ca. 5 cm wide at the middle, the posterior lobes 5-5.5 cm long, the posterior lobes soon pinched off and directed outward at 45° angle, noticeably auriculate at the base; intermediate blades with the lateral segments confluent with the medial lobes. Adult plants with stem to 2.5 cm diam. (fresh), shrinking to 1.5 cm diam., the epidermis green, shiny, drying yellowish brown with sharp longitudinal wrinkles; internodes 2-4 cm long; leaves moderately thin, clustered in the upper 30 cm of the stem; petioles 25-30 cm long, sheathed ca. 2/3 their length, the sheath 4-5.5 cm wide when flattened, free-ending and bluntly acute at the 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 the apex, briefly attenuate at the base; lateral leaflets strongly inequilateral, 16-24 cm long, 10-12 cm wide, the base prominently au-ricled on the outer margin, cuneate on the inner margin, the midrib bluntly depressed above, prominently raised beneath, the primary lateral veins and the principal collective vein weakly sunken above, raised beneath, the tertiary veins clearly visible (on dried specimens); primary lateral veins 6-8 pairs, mostly departing midrib at ca. 40° angle; collective vein ca. 12-18 mm from the margin (midway to the apex).
Inflorescences 2 per axil; not seen in flower. Infructes-cences 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; mature fruits not seen. Figs. 43, 47.

DISTRIBUTION: Syngonium glaucopetiolatum is known from Costa Rica where I have seen it at Monteverde (Guanacaste) and Panama in what is believed to be lower montane wet forest at elevations of 1300-1800 m.
It is distinguished by its large 3-lobed blades with markedly auriculate lateral lobes and by its glaucous young petioles, peduncles, and spathe tubes. The blade shape of S. glaucopetiolatum approaches that of S. mauroanum but that species has been found to range no higher than 450 m and is apparently restricted to premontane moist forest.
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.

PANAMA: CHIRIQUI: East of Boquete, Croat 26821 (MO).