Tuesday, June 3, 2014

Trout Lily - Erythronium americanum - Érythrone d'Amérique

Erythronium americanum (trout lily, fr: Érythrone d'Amérique) is a very long-lived forest understory perennial from the family Lilaceae. It is a spring ephemeral (meaning that the plant emerges and senesces before the forest canopy has closed). This plant is most easily identified by its mottled grey and green leaves; each plant produces either one or two of these leaves, which are arranged basally. The flower is yellow, sometimes with red or purple spots toward the inside; there are six tepals, which can be heavily recurved. The flower is slightly nodding, pointing the ground.

E. americanum - all major points of anatomy visible
The above photograph was taken without damaging the plant; I gently bent the flower stalk down and righted it when I was done. These plants rely on a very narrow window of sunlight in the early spring to store energy in the rhizome for growth and blooming the following year, so it is best to damage them as little as possible.

Note that the anthers are of varying lengths and sizes. They look red here because they have not yet opened to expose the pollen (this flower had opened the same morning that I took the photo).

This flower blooms extremely rarely; some estimate that only about 1/60 plants will bloom in a given year. My observation suggests that this number could be lower in some places, such as where I took these photographs at QUBS. The plants take several years to achieve reproductive maturity, and once achieving it will bloom only occasionally.

E. americanum  - note the heavily recurved sepals

This plant is particularly suitable for certain types of pollination studies where one wants to know which individuals are successfully pollinating other individuals. This is because there is a naturally occurring difference in pollen colour in some of these individuals; the general population has yellow pollen, while occasionally an individual has brown pollen. This allows researchers to take an individual with brown pollen, plant it in amongst individuals with brown pollen, and actually track exactly where the brown individual's pollen ends up going. There are techniques to do this with plants which don't have different flower morphs, but they generally entail putting a fluorescent dye on the pollen and this does somewhat alter its characteristics, eg weight (and is therefore a potential confound).

E. americanum
E. americanum is listed as secure in Canada and secure in most of its US range, except in Iowa where it is threatened.

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