SYNGONIUM SAGITTATUM

PROTOLOGUE: Syngonium sagittatum , published in Gentes Herbarum 9: 372 (1965).

Syngonium sagittatum Bunting, sp. nov. Caudex scandens internodiis stirpium adultarum viridibus 3–5.5 cm. longis 2.7 cm. crassis. Foliorum adultorum lamina subcoriacea plerumque ovata integra, ad apicem acuminata ad basim sagittata, usque ad 49 cm. longa 31 cm. lata, laete viridis sub-bullata, nervis lateralibus primariis utrinque ca. 10 vel pluribus, insculptis, nervis lateralibus secundariis fere aeque validis, lobis posticis rhomboideo-triangularibus ad apices obtuso-angulatis, sinu rhombiformi 11–13.5 cm. profundo sejunctis. Petiolus ad 43 cm. longus, longe vaginatus, vagina apera, in parte tertia superiore ventraliter planatus. Pedunculi bini vel trini, 15 cm. longi. Spatha carnoso-crassa, 26 cm. longa, longe acuminata, ad medium constricta, extus pallide viridis, lamina intus colore roseo suffusa, tubo inflato ca. 12 cm. longo 6.5 cm. crasso intus roseo obscuro. Spadix spatha 7.5 cm. brevior, sessilis, ad basim obliquus, parte pistillata 3.7 cm. longa 2.2 cm. crassa (in anthese), parte staminata ± clavata ad 2.6 cm. crassa; flores staminati 6 mm. longi, flores pistillati fere 5 mm. longi, stigmatibus viscosissimis. Typus: Sierra de Juárez, at Vista Hermosa, 17.9 miles from bridge at Valle Nacional on road to Oaxaca, Oaxaca, Mexico. Epiphyte on trunk of tree; latex abundant; petioles terete above, basal part open-vaginate with margins revolute; infls. paired, spathe tube rose inside. 24 Sept. 1961. Moore & Bunting 8920 (holotype BH, isotype MEXU).

DISTRIBUTION: Mexico (E. Oaxaca, Veracruz): Mexico Gulf, Mexico Southwest, Oaxaca, Veracruz.

DISTRIBUTION NOTE: Mexico: México State, Oaxaca, Veracruz.

SPECIES DESCRIPTION:

Nomadic vine; juvenile plants with stems ca. 1 cm diam., drying weakly verrucose with many slender longitudinal ridges; petioles broadly sheathed ca. 2/3 of their length; blades triangularelliptic, 19–23 cm long, 7–9 cm wide, anterior lobe acuminate at apex, weakly constricted at base, posterior lobes narrowly triangular, rounded at apex. Adult plants with stems to ca. 2 m long, short-creeping, closely appressed to trees; internodes green, 3.0–5.5 cm long, longer toward base of stem, 2.5–4.0 cm wide. Leaves with petiole 37–43 cm long, sheathed 2/3 to 3/4 its length, subterete, weakly flattened laterally above sheath, sheath open, thin along its margin; blades simple, subcoriaceous, ovate and conspicuously sagittate at base, acuminate at apex, 30–50 cm long, 23–31 cm wide; upper surface semiglossy, light green, sub-bullate; lower surface slightly paler, semiglossy, margins revolute; posterior lobes directed somewhat upward at an angle to midrib, usually unequal, rhomboid-triangular, obtusely angular at apex, 12–18 cm long, usually longer than wide, frequently overlapping; sinus spatulate to rhombic or obovate (clavate to hippocrepiform when pressed flat); primary lateral veins 9–11 per side, prominently sunken; some interprimary veins prominently sunken; collective veins weakly sunken above, prominently to weakly raised beneath; basal veins 3–7 pairs, coalescing 1.5–7.0  cm from petiole; basal rib naked 1–5 cm.³

INFLORESCENCE:

Inflorescences 2 or 3 per axil, erect; peduncle ca. 15 cm long; spathe thick and fleshy, 15–26 cm long; spathe tube ellipsoid, 8–11 cm long, 4.5–5.0 cm diam., greenish outside, tinged with violet-purple inside, constriction usually at a point about midway on staminate portion of spadix; spathe blade 14 cm long, long-acuminate and convolute at apex, greenish white; spadix 12.5–17.0 cm long; pistillate portion of spadix 2–4 cm long, 1.5–2.2 cm diam., slightly narrower at apex, pale green, synandrium irregularly 4–6–sided, smooth to bumpy at apex, densely and minutely papillate, 6 mm long, 2–3 mm diam.; staminate portion of spadix 10.5–13 cm long, 2.0–2.5 cm diam., broadest at about middle. Infructescences green, pendent, weakly flattened, ca. 7 cm diam. in broadest view. Collected in flower in February and September and in mature fruit in February.³

ECOLOGY:

Syngonium sagittatum is known for certain only from the Sierra de Juárez in eastern Oaxaca at elevations of 1200–1400 m. The area appears to be in a Tropical wet forest life zone.³ altitude: 1200–1400 m

ETYMOLOGY:

From Latin sagittatus, "arrow-shaped," referring to the sagittate leaf blades. George Bunting described the species from Oaxaca in 1965.³

NOTES:

1. The species is a member of section Cordata and is characterized by its moderately short internodes, petiole sheathed 2/3 to 3/4 its length and subterete above the sheath, the simple, subcoriaceous, ovate and conspicuously sagittate, acuminate blades with the upper surface semiglossy, light green and sub-bullate, by the rhomboid-triangular posterior lobes directed somewhat upward at an angle to midrib, the clavate to hippocrepiform sinus when pressed flat, the primary lateral veins 9–11 per side, basal veins 3–7 pairs with the posterior rib 1.5–7.0 cm long and naked 1–5 cm as well as by 2 or 3 inflorescences per axil, moderately long-pedunculate spathes with tube ellipsoid, greenish outside, tinged with violet-purple inside. The species is apparently most closely related to Syngonium crassifolium (Engl.) Croat of Colombia and Ecuador and has nearly identical leaves. It differs from that species in having a long-acuminate spathe. Syngonium crassifolium has a spathe which is acute or merely short-acuminate at the apex. Despite their similarities, it is doubtful that these two species are the same because of their very disjunct ranges and the fact that no other closely related plants have ever been collected between Mexico and Colombia-Ecuador. Syngonium sagittatum is also related to Syngonium schottianum and Syngonium hastiferum, but of these two species, it is most similar to the former, with which it shares a similar leaf shape and inflorescence. It differs from Syngonium schottianum principally in having a thinner blade which dries green rather than typically whitish as in Syngonium schottianum. The species is probably the same as Syngonium xanthosomaphyllum, which was proposed as a new species (but never published) by Birdsey (1955). However, the collection (Birdsey 300) from near Jalapa, Veracruz, has never been located. Syngonium sagittatum would certainly be expected to occur there.³

REFERENCES:

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

2. Gentes Herbarum 9: 372 (1965) — protologue.

3. Croat 2023. A revision of Syngonium Schott (Araceae-Caladieae) for Mexico, Central America, and the West Indies. Aroideana 46(2)

Additional photos from iNaturalist by Fátima Isabel Parra Rodríguez