SYNGONIUM ARMIGERUM
PROTOLOGUE: Syngonium armigerum , published in Annals of the Missouri Botanical Garden 68: 585 (1982).
Syngonium armigerum (Standley & L. O. Williams) Croat, comb. nov. Basionym: Philodendron armigerum Standley & L. O. Williams, Ceiba 3:107. 1952. Type: Costa Rica, Cartago, on hills near Moravia (SE of Turrialba) on road past Tuis, 1300 m, L. O. Williams 16170 (EAP, holotype; US, isotype).
SYNONYMS:
HOMOTYPIC SYNONYMS: Philodendron armigerum Standl. & L.O.Williams
DISTRIBUTION: Costa Rica to Panama: Costa Rica, Panama.
DISTRIBUTION NOTE: Costa Rica: Cartago, Heredia, Limón Panama: Chiriquí, Colón (Panama), Panamá Province.
SPECIES DESCRIPTION:
Scandent nomadic vines; stems 5–6 mm diam., drying brown with longitudinal wrinkles; internodes 2–4 cm. Leaves persisting at all nodes at least in the upper 30 cm of stem; petioles 5–7 cm, (that of the leaf subtending inflorescence to 10 cm), sheathed nearly to the apex, sheath 5–7 mm wide when flattened, emarginate at apex; blades 8–15 cm long, 3–6 cm wide, simple, oblong to oblong-elliptic, acute to narrowly rounded at apex, apiculate, weakly lobed at base, membranous, dark green and subvelvety above, heavily tinged purple-violet below; posterior lobes broadly triangular or rounded, obtuse, lower surface with obscure black punctations, 5–7 veined at base; primary lateral veins 5 or 6 per side, all arising in the basal half of blade, ascending at a sharp angle to near the apex, each forming a separate collective vein; tertiary veins distinct.³
INFLORESCENCE:
Inflorescences usually one per axil; peduncle to 5.3 cm long, 5 mm diam. (dried); spathe dark violet purple on both surfaces of tube, greenish white on blade outside; spadix 8.7–9.0 cm long, staminate spadix 6.7–7.2 cm long, 0.8–1.8 cm diam.; sterile staminate segment 1.2 cm long, 0.7 cm diam. at base, the lower few spirals of staminodia subrounded to bluntly quadrangular, to 3 mm diam., mostly rounded-prismatic to trapezoidal higher up, drying yellow-brown, truncate, weakly granular; pistillate segment 1.5–1.7 cm long, 0.7 cm diam. at base, 0.8 cm diam at apex, bluntly ounded at apex; stigmas depressed globose, ca. 1 mm diam. syncarp coriaceous, ca. 7 cm long. Flowers known from June & August; fruits from April.³
ECOLOGY:
Syngonium armigerum ranges from Costa Rica to Panama at 290–1300 m elevation in areas of Premontane wet forest and Premontane rain forest.³ altitude: 290–1300 m
ETYMOLOGY:
From Latin armiger, "bearing arms." The original description of the basionym Philodendron armigerum does not spell the allusion out; it most likely refers to the hastate leaf blades, whose basal lobes stand out like the arms of a halberd.²
NOTES:
1. The species is a member of section Cordata and is characterized by its long slender brown-drying internodes, weakly sheathed petioles with sheath emarginate at apex, simple, oblong to oblong-elliptic blades which are acute to narrowly rounded at and apiculate at apex, weakly lobed at base, 5 or 6 primary lateral veins per side arising in the basal half of the blade, one short-pedunculate inflorescence per axil, spathe dark purple-violet on both surfaces of tube, blade greenish white outside. The collecting locality of the Williams' material that forms the type of Syngonium armigerum has been open to doubt., in particular the elevation (1300 m) on Williams's label. Mike Grayum (MO) gave the folliwng account of the possible true locality: There are numerous places in Costa Rica called ‘Moravia', with that in Limón Province located at about 150 m elevation, more than 1000 m lower than that specified on the label. However, it is not inconceivable that Syngonium armigerum could grow in the vicinity of the lower-elevation (Limón) Moravia, especially on the nearby hills, because it has been collected down to as low as 290 m, and perhaps even lower. In fact, Hammel & Chavarría 17068, a superb fertile specimen of Syngonium armigerum, was collected at 200–500 m (according to its) label, in Limón Province, not far from Moravia de Limón. Furthermore, 1300 m would be an unusually high elevation for Syngonium armigerum, which has not otherwise been found above 900 m in Costa Rica. One can imagine that Williams did not get the elevation exactly right, but he was not likely off by 1000 m! Another explanation might be that Williams may have been at ‘Moravia de Chirripó' which is at a similar elevation (1126 m), albeit in Cartago Province. Indeed, Syngonium armigerum could conceivably be found anywhere between the two Moravia's, but it is the association, on Williams's label, of the place-name ‘Moravia' with the elevation ‘1300 m' that implicates Moravia de Chirripó (Prov. Cartago). Another bit of evidence corroborating the ‘Moravia de Chirripó' hypothesis is that Williams's very next collection number, 16171, from the same site and elevation, is a specimen of Philodendron brenesii Standl. There are no records of Philodendron brenesii, in any part of its geographic range, from below 800 m (and it extends upslope to perhaps 1000 m above the elevation of Moravia de Chirripó). So, the chances of it occurring anywhere near the low-elevation Moravia de Limón are essentially nil. There is also a 1984 collection of Philodendron brenesii (Thompson & Rawlins 1230) from Prov. Cartago, in the Cantón de Turrialba (which includes Moravia de Chirripó), at 1150 m. In my mind, at least, there can be no doubt that Williams was near Moravia de Chirripó, and simply got the province wrong, which is understandable (indeed, Moravia de Chirripó is in far eastern Prov. Cartago, not far from the Limón border).³
2. Croat's 1981 section Oblongata, erected for the three oblong-leaved species (Syngonium armigerum, Syngonium llanoense and Syngonium oduberi), was merged into section Cordata in 2023 once new species had blurred the line between oblong and cordate blades.³
REFERENCES:
1. Plants of the World Online, Royal Botanic Gardens, Kew — Syngonium armigerum
2. Annals of the Missouri Botanical Garden 68: 585 (1982) — protologue.