Invasive species walk and talk

The SC/SS 115 Ethnobotany class walk and talk about invasive species focused on field identification of some of the more common invasives. A handout provided a guide to some of the plants that would be visited during the hike.

The first stop was a patch of Ischaemum polystachyum across from the classroom that included Sphagneticola trilobata (yellow flower) and Stachytarpheta jamaicensis (purple flower). The area also featured Commelina diffusa.

Sphagneticola trilobata

Acacia auriculiformis was brought in as a forestry tree and now spreads wild. 

Falcataria moluccana was also brought in and has spread aggressively, however Falcataria moluccana is valuable as firewood and prevents pressure on local trees as sources of firewood. The tree is also a nitrogen fixer and Piper methysticum, which prefers light shade, grows vigorously under Falcataria moluccana.

Clidemia hirta is perhaps the most aggressive invasive to arrive and is a shade tolerant invasive. Clidemia hirta arrived perhaps ten years ago somewhere out here in Palikir, perhaps a few years earlier. Clidemia hirta also appears to have allelopathic capabilities.

Hippobroma longiflora is a known neurotoxic plant and is the toxic plant children are most likely to get into. Merely picking the flowers leaves toxin on the hands which can burn the eyes when the child rubs their eyes.

Clerodendrum quadriloculare is another aggressive, shade tolerant, allelopathic plant. This plant is superb at establishing patches wherein this is the only plant that can grow. This plant can also grow in full sun.

A third shade tolerant and aggressive plant is Cheilocostus speciosus. Hairy and somewhat "itchy" when cutting large amounts of the plant, the good news is that the plant is not sun tolerant.

Bidens alba, also known as beggar's tick, is a sun-only invasive. Mimosa pudica is also found out in this open area.

Hyptis capitata is another sun only invasive, here growing amid Ischaemum polystachyum.

Pennisetum purpureum

Using biological control on Clidemia hirta is probably not an option: Melastoma malabathricum var. marianum is another melastome that might be impacted by a Clidemia hirta bio control. Locally this plant is known as pisetikimei, although Luelen Bernard spelled this as kisetikmei.

A bio control was released for Chromolaena odorata, the effects of which can be seen here. The bio control has not eliminated the plant, but has greatly reduced the ability of the plant to compete.

Class wrapped up as a rain front moved in from the east complete with a double rainbow and Alexander's dark band.