SYNGONIUM ANGUSTATUM
PROTOLOGUE: Syngonium angustatum , published in Oesterreichische Botanische Zeitschrift 8: 178 (1858). The protologue is reproduced below.
SYNONYMS:
HETEROTYPIC SYNONYMS: Nephthytis triphylla Nash; Syngonium albolineatum W.Bull; Syngonium gracile Matuda; Syngonium oerstedianum Schott; Syngonium podophyllum var. albolineatum (W.Bull) Engl.; Syngonium podophyllum var. oerstedianum (Schott) Engl.
DISTRIBUTION: Mexico to C. Panama, San Andrés and Providencia: Belize, Costa Rica, Guatemala, Honduras, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Southeast, Mexico Southwest, Nicaragua, Panama.
DISTRIBUTION NOTE: Belize: Belize, Cayo, Corozal, Orange Walk, Stann Creek, Toledo Costa Rica: Alajuela, Guanacaste Guatemala: Alta Verapaz, Guatemala, Izabal, Petén Honduras: Atlántida, Colón, Comayagua, Cortés, Gracias a Dios, Olancho, Yoro Mexico: Campeche, Chiapas, México State, Quintana Roo, San Luis Potosí, Tabasco, Tamaulipas, Veracruz, Yucatán Nicaragua: Boaco, Carazo, Chontales, Granada, León, Managua, Matagalpa, North Caribbean Coast, Nueva Segovia, Rivas, Río San Juan, South Caribbean Coast Panama: Colón (Panama), Panamá Province POWO: San Andrés and Providencia (Southwest Caribbean) iNaturalist: Campeche, Cayo, Chiapas, Quintana Roo, Tabasco, Veracruz.
SPECIES DESCRIPTION:
Nomadic vine; juvenile plants with stems not glaucous, usually sparsely muricate; petioles sheathed usually less than 1/3 their length; blades dark green, marked on upper surface along principal veins with gray-green, cordate, less than 6 cm long, anterior lobe ovate, posterior lobes suborbicular; intermediate leaves sagittate or hastate, acuminate at apex; adult stems not glaucous, sparsely muricate; internodes mostly 2–10 cm long on flowering stems. Leaves with petioles sometimes pruinose, sheathed 1/2–4/5 their length, 15–40 cm long; blades pedatisect, dark green above, sometimes grayish green on midrib and rarely on lateral veins; leaflets 3–11, usually conspicuously free from one another, lowermost auriculate, median leaflet elliptic to oblong-elliptic to oblanceolate, acuminate at apex, attenuate, acute or cuneate at base, 11–31 cm long, 4–10 cm wide, rachis gradually curved, lateral leaflets inequilateral, inner margin acute to cuneate, outer margin rounded to auriculate, auricle rounded to bluntly acute, rarely slightly pinched off; primary lateral veins 3–5 per side, sunken above, raised beneath; tertiary veins distinct.⁴
INFLORESCENCE:
Inflorescences to ca. 7 per axil; peduncle glaucous, almost 3-sided, 5–10 cm long, and erect at anthesis, to 17 cm long and pendent in fruit; spathe 7–14 cm long; spathe tube elliptic, 2–5 cm long, 1.0–2.5 cm diam., green and usually glaucous outside, green inside; spathe blade cream on both surfaces, 6–9 cm long, 1.5–3.5 cm wide, acuminate at apex; spadix 3.8–10.3 cm long; pistillate portion of spadix 1.3–2.6 cm long, 5–10 mm diam., greenish, flowers irregularly hexagonal, stigma discoid; staminate portion 2.5–6.5 cm long, 5–15 mm diam., pale yellow, flowers completely fused into a synandrium with no sign of fusion, apex conspicuously retuse (notched medially). Infructescences usually bright red, sometimes reddish orange, sometimes glaucous; syncarp brown, 2.5–4.5 cm long, 1.5–2.5 cm diam. Syngonium angustatum apparently flowers most abundantly during the early rainy season with some flowering during the dry season as well.⁴
ECOLOGY:
Although most abundant at lower elevations, it ranges up to 1200 m. The species is most abundant in Tropical moist forest life zones, but has been collected in Tropical dry forest life zones in Nicaragua and Costa Rica. It is one of the most well adapted species to dry habitats and it is likely this attribute that makes it adaptable to dry habitats throughout the world where it has escaped from cultivation.⁴ altitude: 1200 m
ETYMOLOGY:
From Latin angustatus, "narrowed," referring to the narrow divisions of the leaf blade. Schott's original description singles the species out by its narrow five- to sevenfold divisions of the blade.²
NOTES:
1. The species is a member of sect. Syngonium characterized by its moderately long non-glaucous internodes which may be sparsely muricate, petioles sheathed 1/2–4/5th their length and sometimes pruinose, 3–11 pedatisect blades with the divisions moderately uniform and narrow with the rachis gradually curved, 3–5 primary lateral veins per side as well as by up to 7 inflorescences per axil with glaucous peduncles with the spathe tube elliptic, green and usually glaucous outside, green inside and a spadix that have the flowers completely fused into a synandrium with no sign of fusion with the apex conspicuously retuse and usually bright red, sometimes glaucous fruiting spathe. Syngonium angustatum is closest to Syngonium podophyllum but can usually be distinguished by its more uniformly slender leaflets, the papillae of the older stems, and the deeply retuse, fused staminate flowers (also see the key). According to Birdsey (1955), the species hybridizes with Syngonium podophyllum in Mexico. ⁴
2. The spadix warms four times, not twice. Measured in a greenhouse on five inflorescences from two plants, the first peak comes in the morning of day two (29.8 ± 2.7 °C at about 09:32, 9.4 ± 4.7 °C above the air), the second in the afternoon (28.4 ± 3.5 °C), the third in the early night (25.7 ± 0.2 °C), and the fourth on the morning of day three with pollen release (28.8 ± 0.1 °C); the spadix, only 4 to 8.5 cm long, never drops to ambient between them. The pollinator is unknown: the authors guessed day-active flies or beetles and called for field studies.⁶ Its morning heat and spiny pollen have since made it the predicted second candidate for the plant-bug pollination found in Syngonium hastiferum, still untested in the field.⁷
3. Floral development was followed by scanning electron microscopy in 25 inflorescences from the Montagnes de Kaw, French Guiana. The staminate flower is a synandrium of three to four (usually four) stamens that fuse very early around a central cavity; the sterile flower is a synandrode of four to six staminodes; the pistillate flowers are usually two-locular with a discoid stigma on a short style. The transition from pistillate to sterile flowers is abrupt, with none of the atypical bisexual flowers seen in Philodendron and Caladium, and small prismatic calcium-oxalate crystals form on the surface of every flower type before the anthers open.⁸
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Syngonium angustatum
2. Oesterreichische Botanische Zeitschrift 8: 178 (1858) — protologue.
3. iNaturalist: Syngonium angustatum
Additional photos by Patrick Blanc
Additional photo by David Scherberich
Additional photos from iNaturalist by Hendra, jlsnaddon, samwilhelm, Micael De Bona, Neptalí Ramírez Marcial, Tiago Lubiana, abcdefgo, frog18k, Jesús Manuel Rivera Hernández, Nunya, renjus box, 卷尾.杰森, 曾粲然, John Li, narido, Patrícia Mees, Rogelio Martínez, scallions and Steve Fitzgerald