Tuesday, February 28, 2017

Sorting Out Hypogymnia


Day 138: Well! That came as a bit of a surprise! I have several Hypogymnias occupying my fence rails and had identified H. inactiva and H. pinnata previously by examining the inside of the tubular thallus. As a group, the Hypogymnias are known by the common name "tube lichens," referring to their hollow structure. Most are black on the reverse and have various degrees of black speckling on the front; some have tubes which are open at the ends, and some fork in distinctive manners. All these characteristics help separate them by species, but when it comes to the trio of inactiva, pinnata and imshaugii, surgery is required to reveal the medullary ceiling. Inactiva's ceiling is black. Pinnata's is dark, and therefore the two can be confused. However, imshaugii's medullary ceiling is white (circular inset). I'm glad I checked! And thus a new name has been conferred upon part of my garden: the Imshaugii Rail.

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