Imshaugia pyxiniformis

Imshaugia pyxiniformis is a rare species of corticolous (bark-dwelling), foliose lichen in the family Parmeliaceae. It is only known to occur at its type locality in the North Region of Brazil. Characteristics of the lichen include its narrow, incised, lack of vegetative propagules, its pale lower , and presence of the substance lichexanthone.

Taxonomy
The lichen was formally described as a new species in 2004 by Australian lichenologist Jack Elix. The type specimen was collected from the Serra do Cachimbo mountain range in Pará, at an altitude between 350 and 500 m; there, in a tall canopy forest, it was found growing on bark in dry vegetation. The species epithet alludes to its superficial resemblance to some Pyxine species. At the time of its publication, the lichen was known to occur only at its type locality.

Description
The thallus of Imshaugia pyxiniformis, tightly attached to the bark and yellow-gray in colour, reaches 3 – in diameter. The individual making up the thallus are 0.8–1.5 mm wide, with incised tips. The underside of the thallus is ivory to pale brown, with many brown rhizines (up to 1 mm long) serving as holdfasts. Isidia and soredia are absent in this species. Apothecia are present; they are sessile, measuring 0.5–1.2 mm wide with a flat or somewhat concave, dark brown. The, which number eight per ascus, are colourless, somewhat spherical to more or less ellipsoidal, and measure 7–8 by 5–7 μm.

The expected results of standard chemical spot tests are : K−, UV+ (intense yellow); and : K+ (pale yellow-brown), C+ (red), KC+ (red), P+ (orange-red). The positive UV test is caused by lichexanthone, which is present as a minor substance. Other lichen products found in Imshaugia pyxiniformis are protocetraric acid (minor), and 4-O-demethylmicrophyllinic acid as a major substance.