Common Name: Polaris Palm
Juvenile Polaris Palm in La Selva. (photographed by Rylie Walsh)

Latin Name: Asterogyne Martiana

Family: Arecaceae

The Polaris Palm can be found throughout Central America in Belize, Guatemala, Honduras, Nicaragua, Costa Rica, Panama, northwestern Colombia, and northwestern Ecuador. This species lives in the wet tropical rainforest understory, ranging from sea level to 1,000 m, but usually below 500 m. It especially appears in the conservation areas OSA and TOR. [2]

The Polaris Palm is common and grows in clusters throughout the understory of Tropical Rainforests.

Coloration and Morphology:
The Polaris Palm is about 1-2 m tall with a trunk of 3-5 cm in diameter. The top of the trunk spouts green leaf sheaths and the bottom is surrounded with old leaf scars. The stem and trunk are solitary and contain no crownshaft. The leaves are 30-60 cm long and 15-28 cm wide, widening at the apex. Each tree contains about 8-15 leaves at a given time. The ends split in a pinnate formation. The pistillate flowers contain white staminate and produce fragrance and nectar. They are arranged in a palmate formation, about 40-90 cm long with 5-8 branches each 25 cm long and 0.8 cm wide. The fruit is a reddish color that turns purple black. It is round shape about 1.2 cm long and 0.6 cm wide. [2]

Reproductive cycle:
The Polaris Palm is an angiospermae, with monocots and commelinids. The Polaris Palms has a life span of between 50 to 100 years, depending on the nutrient availability and climate conditions. The vegetative phase of palms is prolonged because the palm stem grows to its maximum girth below ground because their trunks remain constant in diameter. [1]
Synecological studies show that asynchronous flowering and partitioning of pollinator guilds may be important regulators of gene flow between closely related taxa and may drive the speciation processes [3]. Araceae inflorescences contains a spathe kettle chamber specialized for pollination by small beetles [3]. While several palms additionally pollinate via wind, there is no indication of wind pollination. Insects and bats pollinate Asterogyne martiana in Costa Rica. The Syrphus flies are the primary pollinators [1]. Seed Germination is about 1.3 Months in a temperature of 82-90°F.

The Polaris Palms inhabit regions in the understory tropical rainforest with partial shade and fast draining soil. In Costa Rica we noticed that the Polaris Palm often lived in clusters in the understory. We observed several birds and insects in the area. There are several other palms that cohabitate with the Polaris palm, including: the slender tall-stemmed palms (Pigafetta, Roystonea), the robust- stemmed (Washingtonia), the short-stemmed with an underground stem (Acanthococos, Attalea geraensis), and the climbing palms, with up to 100 m stems (Desmoncus, Calamus). [1]

Bullet ant walking on Polaris Palm leaf. (photographed by Rylie Walsh)
Positive & Negative Interactions:
In order to efficiently utilize the nutrients in nutrient deficient soil, Polaris Palms have developed nutrient traps. The A. martiana captures nutrients cycling in precipitation and litter fall makes it advantageous to survive in the understory. Falling litter and precipitation is funneled to the center of the crown and then the nutrients travel down the stem to the rooting area, which enhances the nutrient-capturing abilities [3].
Some symbiotic relationships include cohabitation with Weevils. Weevils breed in the staminodial tube. Beetles, bees and flies (Calliphoridae, Syrphidae* and Drosophilidae) as well as mammals (e.g. bats and marsupials) and even crabs pollinate the flowers and spread the fruit seeds. [1]
Understanding palms will help to determine the composition of the organisms living in the forest community. Recent studies use understory Asterogyne martiana to study light relationships, especially as regards simple versus dissected leaves [1].

Personal Experiences:
In La Selva I saw more juvenile A. martiana than adult species. I often observed insects, such as beetles and ants crawling on the leaves.

[1] "Asterogyne martiana." Encyclopædia Britannica. Encyclopædia Britannica Online
Academic Edition. Encyclopædia Britannica Inc., 2012. Web. 29 Apr. 2012.

[2] Gargiullo, Margaret, Barbara Magnuson, and Larry Kimball. A Field Guide to Plants
of Costa Rica. New York, New York: Oxford University Press, Inc., 2008. 2.

[3] ¨Raich, James. Understory Palms as Nutrient Traps: A Hypothesis. Gainesville, FL,
Brenesia, 21:119-129. 1983.