A CONSPECTUS OF THE LICHEN GENUS STEREOCAULON ...

I. MACKENZIE LAMB: A Conspectus of Stereocaulon 287
Costa Rica, Venezuela, Ecuador, Peru, Bolivia.
Remarks: resembling St. meyeri B. STEIN, but of smaller stature, with corticated pseudopodetia
of "macrocarpoid" habitus and mostly harmonic phyllocladial branchlets, and
distinct in chemical constitution. Closely related to St. microcarpum MULL. ARG., from which
it differs in the possession of well developed true soredia and in its simpler chemical spectrum.
Morphologically it appears to be indistinguishable from St. rugulosum LAMB, which is chemically
different (furnarprotocetraric acid) and has a less extensive, although partly overlapping
geographical distribution. St. atlanticum is rarely fertile. The record of "Stereocaulon
ramulosum var. farinosum" from the Azores by DEGELIUS (1941) refers to this species.
97. Stereocaulon colensoi BAB.
ex HOOK. F. The Botany of the Antarctic Voyage of H. M. Discovery Ships Erebus and Terror in the
Years 1839-1843 . . . Part 11. Flora Novae-Zelandiae. Part ii. Flowerless Plants: 295 (1855);
NYL. Synopsis Methodica Lichenum, 1 (2): 232 (1860); HOOK. F. Handbook of the New Zealand Flora,
Part 11: 562 (1867); DODGE, Ann. Cryptog. Exot. 2 (2): 110 (1929); MARTIN et CHILD, Lichens of New
Zealand: 155 (1972). - Pilophoron colensoi (BAB.) KNIGHT, Trans. & Proc. New Zealand Inst. 16: 400
(1 883) ; ZAHLBR. Catalogus Lichenum Universalis, 4 : 433 (1 926). - Corynophoron colensoi (BAB).
NYL. Lichenes Novae Zelandiae: 15 (1888).80
Typus: New Zealand, North Island, leg. COLENSO (date ?) (no. 2746) (K, holotypus; H-NYL, isotypus).
Icon. : HOOK. F. 1855, PI. CXXX A. - NYL. 1860, PI. VII, fig. 8 (ceph. algae). - DUVIGN. 1956,
figs. 4 (3, 6. - MARTIN and CHILD 1972, PI. 47, lower fig.
Mat. chim. : atranorin, colensoinic acid, D-mannitol, D-arabitol, unidentified tetrahydroxy
fatty acids, and traces of 5 further unidentified substances. Colensoinic acid, described from
St. colensoi by Fox, KLEIN and HUNECK, 1970, is the depsidone analogue of the depside
perlatolic acid, and has since been found also in some other Stereocaulon species.
Distrib. : New Zealand and Campbell Island. Erroneous record: Fuegia (RASANEN, 1932, =St.
glabrum (MOLL. ARG.) VAIN.).
Remarks: a notable feature of typical St. colensoi are the peculiar cephalodia, which
DUVIGNEAUD (1956) terms "ficoid". They are pyriform-clavate, shortly stalked, usually
with a subaeruginose tinge, with finely granulate to cerebriform-wrinkled surface, solid internally,
containing Stigonema or Scytonema. Their cortex is 15-50 p thick, isabelline-nubilated
and semi-opaque in section, of indistinctly pseudoparenchymatous (not palisadic) structure
with more or less isodiametric, thin-walled cells 3-5 p diam. The structure of the cephalodial
cortex in St. colensoi is unique in being persistently of the primary type, not proceeding to the
development of gelatinized-palisadic tissue as in St. implexum TH. FR. (see LAMB, 1976, p. 358).
Young immature cephalodia may be subglobose with almost smooth surface. In var. caliginosum
the cephalodia are of somewhat different appearance (see below). Pseudopodetia
corticated with verrucose-wrinkled thallus-mantle, and often "macrocarpoid" in habitus.
Apothecia terminal, commonly several clustered, 1.5-3.0mm diam., at first with prominent
paler receptacle (pseudothalline margin) which later becomes more or less reflexed and excluded.
Central cone densely isabelline-nubilated, opaque and compact. Hypothecium
nubilated below, more or less hyaline in upper subhymenial part. Hymenium 9LL120 (-135) p
high. Spores (4) 8-12-septate, finally somewhat constricted at the septa, (35-) 65-90 x 4-6 p.
@@ The epithet Corynophoron was first published by NYLANDER, 1860, as "fere genus proprium",
and 1888 (loc. cit.) as a proper genus, comprising St. colensoi only, mainly on the basis of the peculiar
cephalodia.