Hypogymnia Physodes

Day 168: Collectively, the Hypogymnias are commonly known as "tube lichens." Why? If you examine one closely, you will see that the lobes are puffy, like miniature balloon animals. In some species, this resemblance is accentuated by each lobe being pinched at the base. Hypogymnia physodes does not exhibit these restrictions, but it has another characteristic which makes it relatively easy to identify, and one which gives it its common name of "Monk's-hood Lichen." The inset takes a closer view of the lobe tips, revealing the powdery or granular soralia (asexual reproductive structures) typical of this species. Where the soralia have fallen away, the tubular nature of the lobes becomes obvious. The lower surface of this lichen is black, but if it is separated from the upper layer to reveal the underside of the pale green top (the medullary ceiling), it will be seen to be white. Differences in the colour of the medullary ceiling are also diagnostic when trying to identify Hypogymnias.