MOSSES OF RIMARIKI ISLAND, NORTHERN NEW ZEALAND

by Jessica E. Beever Department of Botany, University of Auckland, Private Bag Auckland

S U M M A R Y

Thirty-three taxa of moss are recorded from Rimariki Island, northern New Zealand, including the rarely collected Eurhynchium ellipticifolium Dix. & Sainsb..

INTRODUCTION

Rimariki Island lies 0.4km off the tip of Mimiwhangata Peninsula on the east coast of northern New Zealand, at latitude 35° 26'S, longitude 174° 27'E. It rises to 60 m and has an area of about 20 ha. The island has a long history of farming, no doubt with concomitant burning, dating from the last century. Rimariki was purchased by Lion Breweries in 1962 and administered by them as part of the Mimiwhangata Farm Park, until it was acquired by the Crown in 1986. The island now forms part of the Bay of Islands Historic and Maritime Park.

Since farming ceased in the 1940's or 1950's regeneration of vegetation has occurred, and much of the island is now covered with scrub communities to 3 m tall, dominated by flax (Phormium tenax) or karo (Pittosporum crassifolium). A small area of scrub dominated by manuka (Leptospermum scoparium), 1 m to 3 m tall, is found on the northern side of Kohekohe Valley, the only large valley on the island. The coastal cliffs have large pohutukawa, and these, with a single large kohekohe (Dysoxylum spectabile) in a small remnant of coastal forest at the head of Kohekohe Valley, plus a macrocarpa {Cupressus macrocarpa) tree in Flaxbush Bay, are the only sizeable trees on the island. In the coastal forest remnant, and elsewhere on the island, individual cabbage trees (Cordyline australis) are found. Open areas occur on the coastal cliffs, and along the cliff tops and ridges. There are two small streams, neither of them permanently flowing, draining into Flaxbush Bay. A n account of the vascular flora of Rimariki, together with a detailed map of the island, is provided by Cameron (1986).

The present account of the mosses of Rimariki Island is based on collections and notes made during a 5 day visit to the island in December 1982 by the Offshore Islands Research Group.

A N N O T A T E D SPECIES LIST

Mosses are listed alphabetically, in families. Specimen numbers refer

TANE 31, 1985-86 41

to vouchers in the herbarium of the Botany Department, University oi Auckland (AKU).

Philonotis tenuis (Tayl.) Reichdt. On earth or rock exposed or partially shaded. A K U 70413. Eurhynchium ellipticifolium Dix. & Sainsb. Locally abundant, and bearing many capsules, on damp soil and litter in several shaded sites under Phormium tenax and Blechnum capense along the lower reaches of the larger stream draining in to Flaxbush Bay. A K U 70397-70399.

?E. muriculatum (Hook.f. & Wils.) Jaeg. On soil, and on the base of Cordyline australis, shaded. Sterile material only. A K U 70400. Rhynchostegium tenuifolium (Hedw.) Reichdt. On soil or litter, and epiphytic on the base of Cordyline australis, in partial shade. A K U 70416, 70417.

B R Y A C E A E Bryum argenteum Hedw. On soil, exposed or partially shaded. A K U 70383.

B. billardieri Schwaegr. var. ?billardieri Small plants, tentatively placed here on the basis of their weak leaf border, collected from the shaded base of Cordyline australis. A K U 70384.

var. platyloma Mohamed Terrestrial in scrub, shaded. A K U 70385.

B. dichotomum Hedw. In soil pockets on coastal cliffs, exposed. A K U 70386.

B. sauteri B.S.G. On soil, partially shaded. A K U 70387. .B.sp (undescribed) Common in seepages at the base of the greywacke coastal cliffs, exposed. A K U 70378-70380. Leptostomum macrocarpum (Hedw.) Pyl . A single record, small plants on the shaded base of Cordyline australis. A K U 70411.

D I C R A N A C E A E Campylopus clavatus (R.Br.) Wils. On soil, exposed or partially shaded. A K U 70389. C. introflexus (Hedw.) Brid. On soil, exposed. A K U 70392, 70393. C. pyriformis (K.F. Schultz) Brid.

A single record, on soil, partially shaded. A K U 70394.

DITRICHACEAE Ditrichum difficile (Dub.) Fleisch.

B A R T R A M I A C E A E

B R A C H Y T H E C I A C E A E

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FISSIDENTACEAE

H Y P N A C E A E

H Y P N O D E N D R A C E A E

H Y P O P T E R Y G I A C E A E

L E M B O P H Y L L A C E A E

P L A G I O T H E C I A C E A E

POTTIACEAE

P T Y C H O M N I A C E A E

On coastal cliffs, exposed. A K U 70396.

Fissidens humilis Dix. & Watts var. angustifolius Dix. On earth in intermittent watercourse, shaded. A K U 70397. F. leptocladus C. Muell. & Rodw. On soil or rock, in intermittent watercourses and coastal seepages, exposed or shaded. A K U 70402, 70403. F. pungens C. Muell. & Hampe On shaded soil, and on the shaded base of Cordyline australis. A K U 70404. F. tenellus Hook.f. & Wils. On shaded soil, especially along intermittent water courses and also epiphytic on the base of Cordyline australis. A K U 70406, 70407.

Hypnum chrysogaster C. Muell. A single record, partially shaded, on litter in an open grassy area. A K U 70405. H. cupressiforme Hedw. On soil, partially shaded. A K U 70408.

Hypnodendron ?comatum (C. Muell.) Mitt, ex Touw A single finding of sterile plants, partially shaded under manuka. A K U 70409.

Cyathophorum bulbosum (Hedw.) C. Muell. A single record of depauperate plants, shaded on the base of Cordyline australis. A K U 70395. Lopidium concinnum (Hook.) Wils. A single record of depauperate plants, shaded on the base of Cordyline australis. A K U 70412.

Camptochaete arbuscula (Smith) Reichdt. On exposed roots of large kohekohe, shaded in coastal forest remnant. A K U 70388.

Isopterygium minutirameum (C. Muell.) Jaeg. A single record, shaded, on burnt wood. A K U 70410.

Barbula australasiae (Hook. & Grev.) Brid. On rough greywacke on coastal cliffs, exposed. A K U 70381.

Trichostomum brachydontium Bruch On soil or rock, exposed or partially shaded. Common on the coastal cliffs. A K U 70422-70424. Triquetrella papillata (Hook. f. & Wils.) Broth. On soil, exposed. A K U 70426.

Ptychomnion aciculare (Brid.) Mitt.

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On soil or litter, as well as epiphytic on the base of Cordyline australis, partially shaded. A K U 70414.

R A C O P I L A C E A E Racopilum convolutaceum (C.Muell.) Reichdt. On soil or litter, shaded. A K U 70415.

S E M A T O P H Y L L A C E A E Sematophyllum amoenum (Hedw.) Mitt. On litter, and epiphytic on base of Cordyline australis, shaded. A K U 70418.

THUIDIACEAE Thuidium furfurosum (Hook.f. & Wils.) Reichdt. On soil or loose rock, and on base of Coprosma macrocarpa, exposed or partially shaded. A K U 70420.

DISCUSSION

The thirty-three taxa of moss recorded here for Rimariki Island represent a small portion of the northern New Zealand coastal moss flora. Coastal cliff species and mosses of open ground are well represented in the list, shade demanding species less well so. In only a few sites were mosses found growing in any luxuriance. One such site was under the area of manuka scrub in Kohekohe Valley where a well developed sward of terrestrial mosses, Ptychomnion aciculare, Thuidium furfurosum, together with fruiting plants of Bryum billardieri var. platyloma and Campylopus introflexus was found. Here also were recorded the only umbrella mosses on the island, a patch of small plants probably referrable to Hypnodendron comatum. In more open, drier, habitats Thuidium furfurosum was occasionally luxuriant, while well developed patches of Eurhynchium ellipticifolium and Bryum sp.(unde-scribed) were found in certain damp sites.

E. ellipticifolium was originally described in 1945 from material collected by K.W. Allison between Lake Rotoehu and the Bay of Plenty coast (Sainsbury 1945), and there have been very few collections since. It is not apparent whether this moss is truly rare, or simply overlooked, since in the Brachytheciaceae 'even experienced collectors have trouble in identifying specimens' (Allison & Child 1971). The undescribed species of Bryum has been collected widely on the mainland (J.T. Linzey pers. comm.) and on several of the northern offshore islands (Beever et al 1986).

The forest component of the moss flora on Rimariki is, not unexpected­ly, at present rather depauperate. The small remnant of coastal forest supported a few forest mosses including Camptochaete arbuscula, Cyathophorum bulbosum, and Lopidium concinnum. However, each was recorded at a single site only and in the case of the latter two species, only very small, sterile plants were seen. Eleven moss species were

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recorded growing epiphytically but in no case were they growing more than 0.5 m above ground level, and in most cases the plants were poorly developed. As regeneration of the vegetation continues on the island it will be of interest to observe whether forest mosses become better established, and whether additional species will be recruited from the mainland.

A C K N O W L E D G E M E N T S

I am grateful to members of the Offshore Islands Research Group for assistance in the field, especially to E.K. Cameron, C.N. Taylor and R.E. Beever for their contributions to the moss collections, and to the Mimiwhangata Farm Park Charitable Trust for permission to camp and to collect mosses on the island. I thank R.V. Grace and E.K. Cameron for information about Rimariki, E.K. Cameron and R.E. Beever for comments on a draft manuscript, the Directors of the DSIR Divisions at the Mt Albert Research Centre for use of facilities, and the Scientific Research Distribution Committee of the N.Z. Lottery Board for financial support.

R E F E R E N C E S

Allison, K.W. & Child, J . 1971: 'The mosses of New Zealand'. University of Otago Press, Dunedin.

Beever, J . E . , Wright, A .E . , Whitehead, M.D., Barnes, F. and Scofield, R.P. 1986: Mosses of the Broken (Pig) Islands, northern New Zealand. Tane 31: 105-110.

Cameron, E.K. 1986: Vascular flora and vegetation of Rimariki and associated islands, Mimiwhangata, north-east New Zealand. Tane 31: 47-74.

Sainsbury, G.O.K. 1945: New and critical species of New Zealand Mosses. Transactions of the Royal Society of New Zealand 75: 169-186.

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