Mr. Hunt recounts these striking instances. The leaves of the _œnothera
macrocarpa_ are said to exhibit phosphoric light when the air is
highly charged with electricity. The agarics of the olive-grounds of
Montpelier too have been observed to be luminous at night; but they
are said to exhibit no light, even in darkness, _during the day_. The
subterranean passages of the coal-mines near Dresden are illuminated by
the phosphorescent light of the _rhizomorpha phosphoreus_, a peculiar
fungus. On the leaves of the Pindoba palm grows a species of agaric
which is exceedingly luminous at night; and many varieties of the
lichens, creeping along the roofs of caverns, lend to them an air of
enchantment by the soft and clear light which they diffuse. In a small
cave near Penryn, a luminous moss is abundant; it is also found in the
mines of Hesse. According to Heinzmann, the _rhizomorpha subterranea_
and _aidulæ_ are also phosphorescent.--See _Poetry of Science_.