Flora of New Zealand Series

Holotype: New Zealand. Taranaki, Mt Egmont, on volcanic rock, 910 m, A. S. D. King, 28 April 1969, CHR 343143!

Thallus crustaceous-leprose, diffuse, forming scattered aggregations of granules which in places tend to merge to form a non-areolate crust, deep yellow with a slightly orange tinge. Surface composed entirely of a mass of pulverulent, minutely spherical granules to 0.1 mm diam., cortex absent and thallus unstratified, being yellow throughout, thallus margin absent, prothallus not apparent. Hyphae 2-3 µm diam., colourless, obscured by numerous crystals. Sporocarps and pycnidia absent. Chemistry: Thallus C- or faint orange, K+ violet-red. Parietin.

N: Mt Ruapehu, Mt Egmont.

Endemic

Leproplaca lutea closely resembles L. chrysodeta in morphology but differs in the deep, bright yellow colour of its thallus in comparison with the dull brownish-yellow colour of L. chrysodeta. This last species is confined to limestone, whereas L. lutea grows on acid rocks of volcanic origin. L. lutea looks similar to Chrysothrix candelaris, but differs in its granular appearance and especially in its chemistry, as reflected in the K+ violet-red test for parietin. Sterile specimens of Caloplaca citrina might also be mistaken for the new species, but that lichen is markedly less vivid in colour and displays much variation in soredial granule size.

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* Description and discussion of this species by J. R. Laundon, Botany Department, British Museum (Natural History), London.