Flora of New Zealand Series

=NYLANDERIELLA Hue, 1914

Type: Siphula ceratites (Wahlenb.) Fr. [=Baeomyces ceratites Wahlenb. (see Brusse 1987)]

Type : Nylanderiella medioxima (Nyl.) Hue [=Siphula decumbens Nyl.]

Description : Flora (1985: 522).

Siphula is a cosmopolitan genus of c. 26 species included in the family Icmadophilaceae (Stenroos et al. 2002c; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005), a view supported by molecular data (Platt & Spatafora 1997, 1999; Stenroos & De Priest 1998a; Stenroos et al. 2002c). Recent molecular results from six species of Siphula show that the genus as presently defined is polyphyletic and in need of reclassificiation (Stenroos et al. 2002c). Species are invariably sterile (though some are often parasitised by lichenicolous fungi [Hue (1914b: 509) misunderstood this when he created the genus Nylanderiella Hue for the New Zealand species Siphula medioxima Nyl. (=S. decumbens Nyl.) parasitised by a lichenicolous fungus having 1-septate ascospores]), characterised by an erect to decumbent, foliose to fruticose thallus, attached to the substratum by a well-developed rooting system of entangled, branching rhizomorphs (important in consolidating soils) that is easily fractured when specimens are collected. Species of Siphula most frequently occur on moist, peaty or inorganic soils in heaths and moorland from s.l. (Stewart I., and around Fouveaux Strait on the Awarua Plain), to subalpine and high-alpine habitats in North and South Is (Galloway 1985a; Kantvilas 1987, 1994a, 1996a, 1996c, 1998b, 2000a; Kantvilas & Jarman 1999). Species also occur as epiphytes among mosses on tree trunks in temperate rainforest from s.l. to treeline. In the absence of apothecial or pycnidial characters, thallus chemistry (Bendz et al. 1965; Santesson 1967, 1969) is very useful in recognising and delimiting species and is used as a specific character by Kantvilas (1987, 1996c, 1998b, 2002a, 2004k) and Kantvilas & Elix (2002). In a recent overview of the genus Kantvilas (2002a) recognises four infrageneric groupings in Siphula based on chemical and morphological considerations, viz.: (1) the Siphula fragilis group – characterised by broad, fragile lobes, sometimes containing depsidones including S. elixii, S. foliacea and S. fragilis; (2) the Siphula complanata group – characterised by terete to flattened, brownish lobes, mostly containing dibenzofurans, including S. comata, S. complanata, S. georginae and S. jamesii; (3) the Siphula decumbens group – characterised by flattened, chalky lobes containing depsides, including S. abbatiana, S. coroiacea, S. dissoluta, S. fastigiata, S. gracilis, S. mascarena, S. pickeringii, S. ramalinoides, S. subulata, S. torulosa and S. verrucigera; (4) the Siphula ceratites group – characterised by terete to flattened lobes, containing the chromone siphulin and/or related compounds.

Siphula was comprehensively studied by Rolf Santesson in the 1960s and 1970s, but apart from a small report (Santesson 1968) his monograph, though substantially complete, remains unpublished. The current application of the name and a case for the conservation of Siphula in the sense of Fries (1831) was outlined by Brusse (1987). Siphula has a single, widespread species [S. ceratites (Wahlenb.) Fr.] in arctic-alpine habitats of the Northern Hemisphere, with the remainder of the species occurring in the Southern Hemisphere (Hawai'i, southern Africa, South America, Australasia and the subantarctic islands). Hawai'ian species are documented by Magnusson & Zahlbruckner (1945: 27–31) and Magnusson (1955: 364–365), and South African species were monographed by Mathey (1974). Recent studies on the genus in Tasmania (Kantvilas 1987, 1994a, 1996c, 1998b, 2002a, 2004k), Australia (Kantvilas 2004k), South America (Kantvilas & Elix 2002) and South Africa (Kantvilas et al. 2003) are the most detailed yet to appear for Southern Hemisphere taxa, and these papers contain much useful information on New Zealand species as well. A very recent molecular study of 11 species of Siphula s. lat. (published when this book was in page-proof stage) shows Siphula, as currently circumscribed (see above), to be heterogeneous with at least two distinct lineages present (Grube & Kantvilas 2006). The core lineage, comprising the generitype, S. ceratites, and the S. decumbens group, is accommodated in the family Icmadophilaceae. The other lineage, which includes S. complanata, S. fragilis and their allies, has apparently evolved within the Coccotremataceae, and a new genus, Parasiphula Kantvilas & Grube, proposed for these taxa (Grube & Kantvilas 2006). This demonstrates a situation of parallel evolution of distinctive morphological lines that have lost sexual stages and that propagate through thallus fragmentation (Grube & Kantvilas 2006). Six species of Parasiphula are included here within this treatment of Siphula s. lat.

Siphula was a particular favourite of the late Peter Child who made many collections of it from high-alpine habitats in Otago and elsewhere. On present evidence New Zealand is a major area of speciation (Kantvilas 2002a) with 12 species recorded here.