Syngonium podophyllum

arrowhead vine

 

Syngonium podophyllum

Schott 1851

pronounced: sin-GO-nee-um poh-doh-FILL-um

(Araceae — the arum family)

 

common name: arrowhead vine

Syngonium is from two Greek words, συν- (syn-), together, and γονη (goné), the womb, referring to the united ovaries in the flowers; podophyllum is also Greek, πους, ποδος (pous, podos) a foot, and φυλλον (phyllon), a leaf, referring to the shape of the adult leaves of this species.

There are several of these vines growing in gardens on Magnetic Island, particularly in Picnic Bay. The vine is native to Central America, from Mexico to Panama. It has established invasive populations in the USA, South Africa, Singapore, the Caribbean, and on several Pacific islands. These populations can be dense, and displace surrounding vegetation. The vine has the ability to spread in the deep shade of intact forests, forming a dense mat on the forest floor as well as climbing trees. The stems by which it climbs are thick and fleshy, giving it a weight much greater than that of most native vines, thus potentially making trees top-heavy and more susceptible to toppling in a strong wind. It is particularly invasive in Florida, where it has displaced many native plants, including rare ferns. In some areas it has created a thick ground cover that is largely impenetrable to other plants.

This is a perennial evergreen climber with a milky sap, with stems rooting at the nodes. The plant is a good example of heterophylly – more than one form of leaf on the same plant. When the plant develops at the level of the soil, it presents sagittate leaves of a dark green colour on the upper leaf, pale green on the lower, 8–20 cm long with petioles up to 40 cm. As soon as it finds a support – tree or rock – on which it can climb, adhering with its aerial roots, the leaves become pedate, divided usually into 5–9 lobes; the middle lobe is ovate, up to about 25 cm long and 6–12 cm broad, and at this point the plant enters the reproductive stage.

The axillary inflorescences, usually in groups to 3–8, have a white spadix about 8 cm long, surrounded by a spathe, closed and bulb-shaped in the lower part for about 5 cm of its length, of a greenish colour changing to red as the fruits ripen, open and ephemeral in the upper part for a slightly longer length than that of the lower part. This section of the spathe is cream. As the fruits ripen, their weight brings them down from the original upright position, so that they dangle.

The flowers are unisexual. The female flowers are grouped on the lower part of the spadix, and are receptive before the ripening of the masculine ones, thus avoiding self-fertilization. The masculine flowers are on the upper section of the spadix, separated from the female ones by a sterile zone about 1 cm long. As the upper part of the spathe drops off, the female flowers are still enclosed in the lower part. This bulging area surrounding the female flowers looks closed, but when the female flowers are receptive, an opening develops just large enough for the pollinators to enter. After pollination, the opening closes again. As the fruits inside the lower part of the spathe ripen, the male part of the spadix falls off, leaving an attractive red fruit receptacle, which is obviously inviting seed-dispersing fruit-eaters to a snack.

 

Photographs taken at Picnic Bay 2008-2011
Page last updated 15th April 2019