Tropaeolum emarginatum

Tropaeolum emarginatum is a flowering plant belonging to the family Tropaeolaceae. That family occurs naturally only in the New World, and comprises only the single genus Tropaeolum,^[1] in which all the species commonly are known as nasturiums.

Tropaeolum emarginatum, like all species of Tropaeolum, displays these prominent features:^[2]

• It is an herbaceous, hairless annual with unbranched stems that often climb.
• Its leaves arise singly where they attach to their stems.
• Leaf blade margins are not toothed or cut, but can be wavy to deeply lobed.
• Petioles, often twining, attach to the leaf blade at a point within the blade's undersurface (peltate), not at the blade's base.
• Flowers on pedicels display bilateral symmetry.
• At least one of the flowers' lower sepals elongate into a slender Nectar spur.
• Fruits are schizocarps which break into one-seeded sections called mericarps.

Among the 80 or so known species of Tropaeolum, these features further distinguish Tropaeolum emarginatum:^[3]

• Stems are relatively long and may climb up to about 8 m (26 ft) high.
• Petioles reach up to 9 cm (3.5 in) long
• Leaves are rounded with wavy margins usually producing 5 shallow lobes.
• Blades have 5 or more principal nerves, of which the middle three are not forked but side nerves are.
• Sepals are reddish or sometimes somewhat greenish yellow, the spur normally being red but sometimes greenish-tipped.
• Spurs are straight or slightly curved, reaching up to 25 mm (1 in) long.
• Petals bear fringes of short, hair-like cilia at their apexes.
• Petals are yellow, the upper ones often with a purple spot, though the lower ones lack the spot.
• Upper petals are of the same size or bigger than the lower ones.

Tropaeolum emarginatum occurs from southernmost Mexico, the state of Chiapas, south into Colombia.^[3]

In Panama, Tropaeolum emarginatum has been collected in mountains between ~1800 and 2130m (6000-7000 feet).^[3] Also in Panama it has been documented inhabiting a light gap in a mixed forest in which oak, Podocarpus, magnolia and Symplocos were common.^[4]

In Mexico, it has been documented in a clearing in a mountain's cloud forest.^[5]

Within the genus Tropaeolum, traditionally Tropaeolum emarginatum has been assigned to the section Tropaeolum. A phylogenetic analysis of the year 2000 did not change that.^[6]

The genus name Tropaeolum is New Latin from the Latin tropaeum, meaning "trophy". This refers to the shied-shaped leaves and helmet-shaped flowers.^[7]

The species name emarginatum is from the Latin emargino, meaning "to deprive of its edge".^[8] This could derive from the idea that sinuses between the leaves' shallow lobes represent areas where leaf edges are deprived of a presence.