An uncommon lichen Menegazzia pulchra found on the Chatham Islands

[i]Menegazzia pulchra[/i] Photo: Peter de LangeMenegazzia pulchra Photo: Peter de LangeWhile our knowledge of New Zealand lichens is rapidly growing we are still unclear of what is present over large parts of the New Zealand Botanical Region. One key area of lichen ignorance is the Chatham Islands. The current lichen flora (Galloway 2007) records just 48 species for the islands. Yet despite that, the Chathams are the type locality for three species, and one of these, Caloplaca maculata, is endemic to the islands (see Galloway 2007; Johnson 2008; de Lange 2009).

In 1996 two of us, Peter de Lange & Gillian Crowcroft, visited the islands for their first time during which they collected a few lichens from the southern part of Rekohu (Chatham Island). Since then, but most especially in 2007 and 2008, Peter de Lange (mostly aided by Peter Heenan), has made a special effort to collect lichens to improve our knowledge of their diversity on the island. As a result of these gatherings, Peter de Lange and David Galloway (the author of the New Zealand Lichen flora series (Galloway 1985, 2007)) are working with the other key Chatham Islands lichen collectors Peter Johnson and Allison Knight, and lichenologist Dan Blanchon to prepare a checklist of the lichen flora for that island group (Galloway et al. in prep.). As part of that project they have been systematically working through all known collections from the island group held in New Zealand herbaria. In the process some rather interesting and at times unexpected finds are being made.

One of these has been the recognition of Menegazzia pulchra (Parmeliaceae) from Rekohu (Chatham Island). Hitherto this uncommon species was known only from a very small area of beech (Nothofagus) forest in the Waimakariri River catchment centered on the Craigieburn Range, Canterbury (Galloway 1983, 1985, Galloway 2007). As the species name implies Menegazzia pulchra is an attractive species easily distinguished from the 19 other species accepted for the New Zealand lichen flora (Galloway 2007) by the cup-shaped fruiting bodies (apothecia) which have distinctive bright orange-red margins. To date it has only ever been found in association with mountain beech (Nothofagus cliffortioides) forest and has perhaps come to be viewed as an obligate beech forest endemic (see Galloway 1985).

The Chatham Islands gathering was made in February 1996 from the Rangaika Scenic Reserve, Southern Tablelands, Rekohu (Chatham Island). At that time it was not identified and it had remained in a box of Peter de Lange's undetermined Chatham Islands lichen boxes held at the Auckland War Memorial Museum Herbarium. During June 2010 while Peter was sorting out these lichen gatherings for David Galloway to examine, a number of Menegazzia specimens were located, and one of these was immediately recognised as M. pulchra on account of the distinctive colouration of the apothecia. The identification was subsequently confirmed by David Galloway.

The gathering had been made from the upper canopy branches of matipo (Myrsine chathamica) in the tarahinau (Dracophyllum arboretum) / matipo forest that form the main vegetation cover along the southern portion and coastal cliffs of the Rangaika Scenic Reserve. The discovery of M. pulchra now adds a fifth Menegazzia species to the islands lichen flora, the others being M. inflata, M. neozelandica, M. nothofageti and M. pertransita (Galloway et al. in prep.). Of these species only M. neozelandica is common, occurring in most forested and shrubland habitats on Rekohu (Chatham Island) and Rangiauria (Pitt Island) though it is apparently absent from the other smaller islands of the group.

The recognition of Menegazzia pulchra from the Chatham Islands parallels that of another lichen Calycidium cuneatum, which is also a species characteristically associated with the beech forests of New Zealand and Tasmania (Galloway 2007). The type gathering of Calycidium cuneatum is a Henry Travers collection from the Chathams Islands, and until recently (2008) that species had not been recorded from there again. It is now known very locally from the Tuku-a-Tamatea Nature Reserve, Southern Tablelands, Rekohu (Chatham Islands) where it grows on the lower moss covered trunks and root plates of tarahinau and matipo. Aside from these Chatham occurrences Calycidium cuneatum is also known from southern Stewart Island where beech forest is also absent (Cockayne 1909; Wilson 1982, 1987). What both Calycidium and Menegazzia pulchra finds suggest is that (amongst other things) diligent searching for these species in other New Zealand non beech forest habitats could be very worthwhile.  Clearly Menegazzia pulchra is not confined to beech forest either. It is also obvious that we still have plenty to learn about our lichen flora especially with respect to their exact habitat preferences and distribution.

References

Cockayne, L. 1909: Report on a botanical survey of Stewart Island. Wellington, Government Printer.

de Lange, P.J. 2009: Chatham Island Lichens. http://www.chathams.co.nz/content/view/198/116/ (accessed 14 June 2010).

Galloway, D.J. 1985: Flora of New Zealand - Lichens. Government Printer, Wellington.

Galloway, D. J. 2007: Flora of New Zealand - Lichens (revised second edition). Manaaki Whenua Press, Lincoln, New Zealand.

Galloway, D.J.; de Lange, P.J.; Johnson, P.N.; Blanchon, D.J.; Heenan, P.B.; Knight, A. in prep. Checklist of the Lichens of the Chatham Islands. Unpublished Draft Checklist held by P. J. de Lange, Department of Conservation, Auckland.

Johnson, P.N. 2008: Lichens. Pp. 111-112. In, Miskelly C, ed. Chatham Islands: heritage and conservation, 2nd edition. Christchurch, Canterbury University Press.

Wilson, H.D. 1982: Stewart Island plants. Christchurch. Field Guide Publications.

Wilson, H.D. 1987: Vascular plants of Stewart Island (New Zealand). Pp. 81-131. In: Vegetation of Stewart Island (New Zealand). New Zealand Journal of Botany. Supplement, 1987.