Flora of New Zealand Series

Holotype: New Zealand. South Auckland, west of Taupo. On Weinmannia racemosa, 14 May 1981. J.K. Bartlett, CHR 381115! Isotype in BM.

Thallus 2-10(-15) cm tall, ± erect to decumbent-straggling, fragile, easily shattered when dry, stalked, attached to substrate by a root-like holdfast, stalk flattened to ± terete in lower part, ± canaliculate above, 1-3 mm diam and 3-20 mm tall, expanded above into a dissected, frond-like lobe. Lobes narrow, ± laciniate 2-4 mm wide, to expanded, 10-15 mm wide, margins crenate- incised or ragged or irregular, ± thickened, ± densely isidiate. Isidia minute, dark brown or greyish-blue, shining, style-forming, ± terete, delicate at first, densely clustered, becoming coralloid-lobulate and eventually ± phyllidiate, dorsiventral with age, primarily marginal, also developing on lamina and thallus fissures and rents, eventually becoming confluent in a diffract crust. Upper surface dark greyish-blue to black or dark red-brown when wet, dull brownish- grey when dry, often white-maculate (×10 lens) in parts, smooth, undulate to ± shallowly faveolate in parts, often cracked, torn or ± fenestrate, stalk dark brown-black. Lower surface dark brown, occasionally pale buff near margins, tomentose, tomentum uniform, thick, brown. Cyphellae white, round to irregular, rather sparse, sunk in tomentum, 0.1-1.8 mm diam. Apothecia not seen.

N: South Auckland (Pio Pio) to Wellington. S: Nelson (Maruia Valley) to Otago (Dart Valley). Among bryophytes on tree boles in damp, humid, shaded habitats. Also in Victoria, Australia.

Australasian

S. caliginosa is characterised by the distinctly stalked, palmate thallus, the isidiate margins, and a blue-green photobiont, which enables it to grow in densely shaded habitats. Because of its dark colour when wet, and its close association with bryophytes towards the bases of large forest trees, it is frequently overlooked and still poorly collected.