Ramalina Ach.
Thallus fruticose, erect or pendulous, heteromerous, tissues radially arranged, branching subdichotomous to irregular, attached to substrate by a holdfast, branches usually flattened, rarely terete or angular-terete, corticate, cortex variable in structure, mechanical tissue usually below cortex either in a continuous zone or net or broken up into strands of longitudinal thick-walled hyphae. Photobiont green, Protococcus. Medulla white, loosely woven, usually filling the interior, in some species the medulla is reduced to a layer below the algae and a ± hollow cavity results. Apothecia short stipitate, terminal or lateral, peltate or cup-shaped, lecanorine, disc matt, yellowish, ochraceous or pale flesh-coloured and often white- or pink-pruinose. Ascospores colourless, long, ellipsoid, straight or curved, 1-septate. Pycnidia with black or hyaline walls, minute, laminal or subterminal. Conidia uniform, cylindrical-elongate 3-5 × 1-2 µm.
Key
Ramalina is a large genus of c. 200 species widely distributed in temperate and subtropical regions. Worldwide the genus is much in need of revision and no monograph has appeared since Nylander [ Bull. Soc. linn. Normandie 4: 101-180 (1870)]. Several regional revisions are available and contain much useful information as does the series of papers on North American species which appeared early this century; [Howe Bryologist 16: 65-74; 81-89 (1913); Bryologist 17: 1-7; 17-27; 33-40; 49-52; 65-69; 81-87, (1914)].
Krog and Swinscow [ Norw. J. Bot. 23: 153-175 (1976)] treat East African species, Krog and James [ Norw. J. Bot. 24: 15-43 (1977)] those from Fennoscandia and the British Isles, and Krog and Østhagen [ Norw. J. Bot. 27: 255-296 (1980)] those from the Canary Islands. Dodge [ Rep. B.A.N.Z. Antarctic Res. Exped. ser. B, 7: 216-221 (1948)] deals with Antarctic species and Malme [ Ark. Bot. 26A (12): 1-9 (1934)] those from South America.
For New Zealand, Zahlbruckner [ Denkschr. Akad. Wiss. Wien. math.-naturwiss. Kl. 104: 362-364 (1941)] records nine species and his list is a reasonably correct view of the species present. Martin [ T.R.S.N.Z. (Bot.) 3: 139-159 (1966); T.R.S.N.Z. (Bot.) 3: 203-208 (1968)] lists 20 taxa in the genus but many of the names given are synonyms of the polymorphic and widespread lowland and coastal species R. celastri. Martin and Child ["Lichens of New Zealand", pp. 145-148 (1972)] discuss ten species, however four; R. otagoensis (nom. nud.), R. ecklonii, R. menziesii, a characteristic reticulate, fenestrate species from Monterrey California and not known elsewhere, and R. siliquosa represent R. celastri. Nine species are at present recognised in the New Zealand flora and discussed below.
In New Zealand, species of Ramalina are, on the whole, lowland and coastal, colonising mainly introduced trees, shrubs, fenceposts and coastal rocks. The two terete, pendulous species, R. arabum and R. myrioclada, are epiphytic on Metrosideros and other coastal trees and shrubs north of Auckland, while in South I., the ± pulvinate species R. glaucescens is widely distributed on divaricating shrubs in inland river valleys and in some subalpine habitats. R. pollinaria has a rather restricted occurrence in subalpine to alpine rock overhangs in sheltered sites. The polymorphic and wide-ranging R. celastri accounts for most of the collections so far made of the genus in New Zealand. Apart from R. glaucescens the remaining species (particularly the sorediate ones) are still poorly collected and understood here. Chemical characters may be important in the delimitation of species in Ramalina (Krog and Swinscow loc. cit. , Krog and James loc. cit. ). Most species contain usnic acid which is produced in varying amounts in the upper cortex of most species and is associated with traces of atranorin. Cortical substances are of no taxonomic importance in Ramalina, but the range of medullary substances produced in some taxa can be useful in confirming, or making, species determinations.
