A CONSPECTUS OF THE LICHEN GENUS STEREOCAULON ...

I. MACKENZIE Lam: A Conspectus of Stereocaulon 273
Crushed thallus or apothecial fragments of Strain 11, when tested with KHO under the
microscope, regularly produce the characteristic red spicular crystals of the potassium salt
of norstictic acid; those of Strain I similarly treated may or may not do so, depending on the
concentration of norstictic acid present. The biosynthetic difference between the two strains
would appear at first sight to be rather insignificant, stictic acid being probably formed from
norstictic acid by 0-methylation in a terminal reaction, but studies with other lichen genera
seem to indicate that the difference is often correlated with a phenotypic morphological
difference, a different distributional pattern, and different ecological preferences, these features
combining to reinforce the chemical evidence to such an extent that distinct species seem to
be indicated; see W. L. CULBERSON'S remarks on the Ramalina siliquosa group (1969, p. 163).
A segregate from St. massartianum characterized by quite different chemical constitution
(atranorin, lobaric acid and porphyrilic acid) and different geographical distribution (Himalayan
region) is St. togashii LAMB (p. 278).
The macroscopic reactions on the phyllocladia in St. massartianum are not always reliable
for distinguishing the two chemical strains, and chromatography is necessary in some doubtful
cases. Specimens of Strain I1 with a low concentration of norstictic acid may give the reactions
Kt-yellow, PD +yellow or -, and therefore not be distinguishable by this means from
St. togashii. Usually in such cases, however, crushed-out carpogonial clavulae, which are
richer in lichen substances than the phyllocladia, will be found to show a few red crystals of
the norstictic acid salt on treatment with KHO under the microscope.
A specimen collected by WISSEL, 1936, in West New Guinea (Irian), Mt. Carstensz, no.
1897 (FH, L), giving a negative reaction with PD, was found by chromatography and UV
spectrum analysis (C. CULBERSON, S. HUNECK) to contain atranorin and an unidentified
substance which appears to be an unknown depsidone. Unfortunately not enough material
was available for a further analysis by other methods.
Japanese material recorded as "Stereocaulon massartianum var. chlorocarpoides, lobaric
acid strain" by YOSHIMURA, 1974, p. 175, probably refers to an atypically esorediate condition
of St. sorediiferum HUE. Some similar specimens, esorediate and morphologically indistinguishable
from St. massartianum, but containing lobaric instead of stictic acid, have been
seen in various herbaria also from Borneo, Celebes, New Guinea and Java. They may
represent an undescribed species differing chemically from St. massartianum, rather than
esorediate states of St. sorediiferum, as their occurrence falls outside the main geographical
area of the latter. How they should be dealt with taxonomically is a problem which we are
unable to resolve at present.
Distrib.: S. E. Asia: Java, Lombok, Sumatra, Celebes, Malaya, Borneo, Philippines, New Guinea,
Formosa; occurring at higher elevations. The distribution of the two chemical strains seems to coincide,
except that Strain I1 has not yet been seen from Formosa, Malaya, Lombok or Sumatra. Records
of "Stereocaulon nesaeurn" from outside this area refer to other species. A specimen in M from
Brazil, leg. GLAZIOU, thus determined by KREMPELHUBER, is St. rarnulosurn (SW.) RAUSCH. MULLER ARG.
(1894) recorded "St. nesaeurn" from New Zealand; the specimen not seen by us, but doubtless referable
also to St. ramulosum.
Remarks: cephalodia sacculate. In the older literature and in herbaria St. massartianum
has figured under the name Stereocaulon nesaeum NYL., an epithet which is however of somewhat
uncertain application and certainly cannot correctly refer to the present species. DODGE
(1929) typified St. nesaeum NYL. on a Javan specimen collected by ZOLLINGER, in PC. This
lectotypification is inadmissable, since in NYLANDER'S original description (Ann. Sci. Nat.,
Bot. ser. 4, 11: 236. 1859) the only locality mentioned is "in insulis Sandwich" (no collector's