A CONSPECTUS OF THE LICHEN GENUS STEREOCAULON ...

I. MACKENZIE LAMB: A Conspectus of Stereocaulon 221
cladia mostly of the paschale-type (but somewhat coarser); (2) cephalodia pulvinate to subglobose,
smooth or verruculose-divided, usually pale br'own, containing either Arostoc or
Stigonema; (3) apothecia large, terminal, often subdividing; (4) usually of tall growth, 4-
8 cm high. MAGNUSSON (1946, p. 92) states that St. grande has longer conidia than St.
paschale. AHTI (1964, p. 24) points out that St. grande seems to be ecologically distinguished
from St. paschale and St. alpinum. While undoubtedly more than a mere ecotypic modification,
St. grande is perhaps not entitled to the rank of a proper species.
19. Stereocaulon groenlandicum (DAHL) LAMB
Occas. Papers Farlow Herb. Crypt. Bot. no. 5: 10 (1973). - Stereocaulon rivulorum var. groenlandicum
DAHL, Meddel. Gronland, 150 (2): 117 (1950).
Typus: S. W. Greenland, Julianehaab Distr., Igalikofjord, Igdleriigssalik, altit. 700-800 m s. m.,
leg. E. DAHL, 1937 (0, holotypus; c, us, isotypes).
Icon.: DAHL 1950, PI. 11, fig. 2, as St. rivulorum var. groenlandicum. -LAMB 1973, figs. 9, 10a, b,
c, 11.
Mat. chim.: the full chemical spectrum (as in the type material) consists of atranorin,
perlatolic acid, anziaic acid, miriquidic acid, and some unidentified substances. Miriquidic
acid is obviously an accessory substance, as many of the specimens seen lack it. A strongly
deficient phase with only atranorin certainly identifiable is also of moderately common occurrence,
which makes distinction from St. depressum (FREY) LAMB difficult.
Distrib. : boreal-arctic, probably circumpolar. Rare in N. Scandinavia: Sweden (Ase~e Lappmark)
and Norway (Nordland, Nord-Trondelag, Tromso, Sogn og Fjordane). More common in the arctic
and subarctic regions: Spitsbergen, Greenland, Canada (N. W. Territ.), U. S. A. (Alaska).
Remarks: most closely related to the mainly Fennoscandian species St. depressum (FREY)
LAMB, which always contains atranorin only. However, as mentioned above, a deficient
phase of St. groenlandicum with atranorin only is sometimes found, and the question arises
as to whether the two species may be synonymous, although St. depressum is usually distinguishable
in its morphology (more flattened and dorsiventral growth-habitus). In the
meantime, it seems best to treat them as separate species. Smaller, more stunted specimens
of St. groenlandicum not clearly showing the characteristic ligneous development of the
pseudopodetia are morphologically hardly distinguishable from St. rivulorum MAGN.
20. Stereocaulon incrustatum FLORKE
Deutsche Lichenen, Lief. IV: 12 (1819); TH. FR. Monographia Stereocaulorum et Pilophororum: 360
(1858); HUE, NOUV. Arch. Mus. Hist. Nat. ser. 3, 10: 255 (1898), as St. tomentosum var. incrustatum;
MAGN. Gijteborgs K. Vetensk.- o. Vitterhdamh. Handl. ser. 4, 30 (7): 59 (1926); FREY, Rabenhorsts
Krypt.-FI. 9, Abt. IV, 1. Halfte: 172 (1932); RAs. Suomen Jakalakasvio: 68 (1951); YOSHIM. Lichen
Flora of Japan in Colour: 177 (1974). - Stereocaulon tomentosum var. incrustatum (FLORKE) SCHAER.
Lichenum Helveticorum Spicilegium, Sect. VI: 276 (1833). - Stereocaulon tomentosum [subsp.] *
incrustatum (FLORKE) NYL. Synopsis Methodica Lichenum, 1 (2): 245 (1860).
Typus: Germany, Schmargendorf in Grunewald near Berlin, "an der Erde in den Tannenwaldungen",
leg. H. G. FLORKE, 1816 (UPS-TH FR, S, isotypes; the holotype in herb. FLORKE not seen by us).
The material distributed with the original description in FLORKE'S exsiccat Deutsch. Lich. no. 77 bears
no indication of locality, but is probably also isotype material. FLORKE, loc. cit., also mentioned
specimens from Rostock, so lectotypification on the Schmargendorf material is necessary (lectotypif.
nov.).
Facultative synonyms: Patellaria tomentosa /3. erecta WALLR. Flora Cryptogamica Germaniae,