76
Physcia alba
(Fée) Müll. Arg.
Thallus foliose, orbicular to irregular, sometimes confluent with other thalli, up
to 5 cm in diam, more or less loosely adnate, fragile. Lobes radiating, flat to
almost concave, truncate and sinuose, up to 1.5 mm wide, but usually narrower,
distinctly separate or sometimes overlapping, the tips often ascending, eciliate.
Upper surface whitish grey to cream-coloured, without pruina, occasionally
with a weak maculation. Soredia and isidia absent. Lower surface white to pale
graphite grey; rhizines concolorous. Apothecia abundant, lecanorine, variable in
size, up to 2 mm diam. but usually around 1 mm, the disc brown to black, the
margin thick and weakly crenulate. Spores brown, 2-celled. Photobiont:
chlorococcoid. Spot-tests: cortex and medulla K+ yellow, C-, KC-, P+ yellow. -
Rare, mainly corticolous in open forests on solitary trees, also found on rocks in
exposed sites above 900 m (Matale District- Nawanagala and Kabaragala).
Physcia atrostriata
Moberg
Thallus foliose, orbicular or irregularly spreading, adnate, 1-4 cm wide, often
coalescing and forming irregular, 5-8 cm wide patches. Lobes 0.5-2.0 mm wide,
plane to weakly convex, irregularly branched, imbricate or not; apices rounded,
incised and often ascending, with marginal lobules, eciliate. Upper surface
whitish grey to pale greenish grey, emaculate, smooth to shallowly undulate,
frosted-pruinose, especially towards the apices. Soralia marginal, lip-shaped-
undulate, developing around sinuses between lobes, but spreading over
extensive areas of upper and lower surfaces. Lower surface mainly ecorticate,
white at the margins, pale tan or brownish centrally, with conspicuous red-
brown to brown-black, corticate, ribbed or nerve-like longitudinal striations; rhizines conspicuous, brown or black.
Apothecia rare (not seen in Sri Lankan material), lecanorine. Spores brown, 2-celled. Photobiont: chlorococcoid. Spot-
tests: upper cortex and medulla K+ yellow, C- KC-, P- (atranorin and zeorin). - Rare, mainly corticolous in open forests
on solitary trees, above 900 m (Matale District- Nawanagala).
Physcia integrata
Nyl.
Thallus foliose, orbicular or irregularly spreading, adnate throughout, 3-6 cm
wide, occasionally coalescing to form larger colonies. Lobes 0.5-2.0 mm wide,
usually densely imbricate, irregularly or pinnately branched, plane to weakly
convex or undulate; lobe margins entire, the tips rounded, often slightly
downrolled; occasionally the inner parts of the thallus becoming dissected into
small (0.3-0.6 mm wide) lobules. Upper surface whitish grey to grey or bluish
grey, with or without distinct white maculae, often greyish white-pruinose at the
apices. Soredia and isidia absent. Lower surface black (apart from the pale lobe
tips); rhizines simple, dense, black. Apothecia lecanorine, rare to abundant,
laminal, 0.5–2.0 mm wide, broadly adnate, the disc dark brown to black,
sometimes with a white pruina; margin entire, smooth. Spores brown, 2-celled.
Photobiont: chlorococcoid. Spot-tests: upper cortex and medulla K+ yellow, C- KC-, P- (atranorin and zeorin). - One of
most common species in high elevation forests above 1000 m and in man-made vegetation, on tree trunks and rocks, in
rather open but moist, subtropical situations (Avissawella, Ratnapura, Pidurutalagala, Horton Plains, Matale, Kegalle,
Kandy, Knuckles mountains, Hinuduma Kanda, Hakgala and Peradeniya, Sabaragamuwa mountains, Sinharaja-
Sinhagala and Athwalthota).
Physcia krogiae
Moberg
Thallus foliose, orbicular or irregularly spreading, adnate to loosely adnate, 1-5
cm wide. Lobes 0.8-2.5 mm wide, plane to weakly concave or convex,
irregularly branched, discrete to imbricate, the margins entire, smooth to sinuose
or irregular; apices rounded, plane. Upper surface grey-white to bluish grey,
often paler at the margins, dull, more or less white-maculate in the centre,
frosted-pruinose especially near the apices. Soralia laminal or rarely
submarginal, maculiform, beginning as small eroding pustules or cracks in the
upper cortex, forming more or less capitate soralia that can coalesce to cover
large parts of the thallus; soredia farinose to granular. Lower surface pale brown
at the margins to dark brown or brown-black in the centre; rhizines sparse,
concolorous with the lower surface, 0.4-0.6 mm long. Apothecia very rare (not observed in Sri Lankan material),
