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Heterodermia obscurata
(Nyl.) Trevis.
Thallus foliose, mostly corticolous. Lobes slightly disjunct to adjacent, more or
less plane, not ascending, with short lateral lobes. Upper surface greyish white.
Lower surface non-corticate, white, with ochraceous orange spots which react
K+ purple and with marginal rhizines. Soralia lip-shaped or recurved, at the
apices of lobes. Apothecia rare (not found in Sri Lankan material), lecanorine,
the margin crenulate to sorediate. Spores brown, 2-celled. Photobiont:
chlorococcoid. Spot-tests: cortex K+ yellow, medulla K+ purple in pigmented
parts, C-, KC-, P+ pale yellow or P-. - Common. mostly corticolous, but also on
wet rocks, above 900 m, in submontane to upper montane forests along stream
margins (Galhiriya estate, Dehigolla Watta upper division in abandoned
habitats, Nawanagala in the Knuckles mountain region).
Heterodermia podocarpa
(Bél.) D.D. Awasthi
Thallus foliose to subfruticose, irregularly lobed. Lobes disjunct to imbricate,
convex, ascending, with lateral lobules, with whitish unbranched cilia along the
margins. Upper surface greyish white to grey. Lower surface non-corticate,
white, with simple to irregularly branched marginal rhizines. Soredia and isidia
absent. Apothecia abundant, apical or subapical, stipitate, lecanorine, the disc
pruinose, the margin lobulate. Spores brown, 2-celled. Photobiont:
chlorococcoid. Spot-tests: cortex and medulla K+ yellow, C-, KC-, P+ yellow. -
Only locally common on twigs and small branches in both moist and open,
sunny situations, also found on dry rocks exposed to the sun (Nawalapitiya and
Laxapana areas).
Heterodermia propagulifera
(Vain.) J.P. Dey
Thallus foliose, the lobes adnate to ascending towards the tips. Upper surface
grey green to white, with black cilia. Lower surface white, with red spots and
marginal, simple rhizines. Soredia mainly found on the secondary lobes.
Apothecia rare (not seen in Sri Lankan material), lecanorine. Spores brown, 2-
celled. Photobiont: chlorococcoid. Spot-tests: cortex K+ yellow, at lobe-tips K+
yellow turning red, C- KC-; medulla K+ red in pigmented parts (with zeorin,
norstictic and salazinic acids and a yellow pigment). - Rare in shaded montane
forest above 1400 m, growing together with mosses (Horton Plains, Kalupahana
in the Knuckles mountain region).
Heterodermia pseudospeciosa
(Kurok.) W.L. Culb.
Thallus foliose, orbicular to irregularly spreading, adnate to loosely adnate, 2-5
cm wide. Lobes 0.7-1.5 mm wide, plane to weakly convex, sublinear-elongate,
dichotomously to subdigitately branched, usually discrete at the periphery,
radiating; apices not ascending, minutely notched, eciliate. Upper surface
greyish white to grey to brownish grey, darker at the lobe tips, pruinose or not,
sorediate; soredia white to bluish grey, in subcapitate soralia at the apices of
short lateral branches. Medulla white. Lower surface corticate, whitish to pale
brown, rarely dark grey in the centre. Rhizines sparse, marginal, concolorous
with thallus or becoming dark or black near apices, irregularly branched, to 1
mm long. Apothecia rare, lecanorine. Spores brown, 2-celled. Spot-tests: cortex
K+ yellow, C–, KC–, P+ yellow; medulla K+ yellow then red, C–, P+ dark yellow. - Rare, mostly on rocks, more rarely
on trees in open but humid situations (Nawalapitiya and Laxapana areas).
Heterodermia queensberryi
Weerakoon & Aptroot
Thallus foliose, forming tufts, divided into linear, grey, flat lobes tapering at the tips, slightly recurved, dichotomously
branched, with black cilia, the latter simple or with many perpendicular branchlets. Upper surface smooth, dull, green in
shaded conditions, greyish white in exposed conditions. Lower surface non-corticate, without rhizines, pale, with
yellow-orange spots towards the centre which react K+ blood red. Soredia granular, grey, on upturned lobed tips, both
