Flora of New Zealand Series

Thallus, dorsiventral, heteromerous, foliose-lobate, mono- or polyphyllous, attached to substrate by central umbilicus, soft, pliable and somewhat leathery when wet, brittle when dry. Upper surface partially or weakly ribbed or folded or reticulate-ridged, to smooth, continuous, areolate-cracked to ± perforate or lacerate, margins sinuous, entire to ragged or incised, rhizinate or not. Lower surface black or pale brownish or pinkish, smooth, or bullate or wrinkled- uneven, rhizinate or not. Medulla white. Photobiont green, Trebouxia. Apothecia sessile to pedicellate, lecideine, discrete, plane to convex, disc black, plane, smooth or with conspicuous ridges (gyrae) or bands of sterile tissue. Ascospores 8 per ascus, simple, ellipsoid, colourless, becoming brown and muriform in some species.

Umbilicaria is a widely distributed cosmopolitan genus of c. 45 species, included in the family Umbilicariaceae. Species are uniformly saxicolous and are found in alpine, subalpine and polar habits. Eleven species are known from New Zealand [Frey Ber. schweiz. bot. Ges. 45: 198-230 (1936); Ibid. 46: 412-444 (1936); Ibid. 56: 427-470 (1949); Llano "A monograph of the lichen family Umbilicariaceae in the Western Hemisphere."Off.Nav. Res. Washington, D.C. 281 pp. (1950); Allan Tuatara 4: 59-62 (1951)]. In this account species accommodated by Llano ( loc. cit. ) in Agyrophora and Omphalodiscus are here included in Umbilicaria following Henssen [ Dtsch. bot. Ges. N. F. 4: 103-126 (1970)]. Species of Umbilicaria are common components of the alpine lichen flora in New Zealand but the group remains to be critically studied here.