Journal Number 89
December 2003

ORIGINAL PAPERS

Kauri Orchids in the Kaimai Ranges
By Graeme Jane, Tauranga

Bruce Irwin first introduced us to the Pterostylis agathicola at the Springs Road Kauri Grove walk not long after we arrived in Tauranga. It is a fairly well established population quite handy to the road.  Over the next couple of years we have found P. agathicola in most stands we have visited. In the Wairoa Stream even a search around two isolated kauri on the river flat (grid ref 27640 60064) yielded a few flowering plants each year.

So it was quite a surprise a few weeks ago to find P. agathicola forming quite a large population under Pinus pinaster in one of those stands that must have been planted after logging in the Ngamuwahine stream, some time in the 1920s or 1930s (grid ref 27729 63735).  The P. pinaster forms a dense canopy. Beneath, there is a sparse understorey of mamaku (Cyathea medullaris) and a range of native shrubs such as privet (Geniostoma ligustrifolium) prickly mingimingi (Cyathodes juniperina) and karamu (Coprosma robusta)

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As the photo shows the P. agathicola was arising from a dense litter of pine needles. So where was the kauri? Probably long gone. The site though, is a typical kauri site, on a ridge top facing north, somewhat stony soiled so perhaps it was there in the recent past. There are no kauri known from that general area today. The nearest that I know of are the southernmost accessible kauri on the other side of the range in Rapurapu Stream (grid ref 27665 63626) where we did not find P. agathicola. (We have yet to visit the site in Wairakau Scenic Reserve). On skiting to Bruce he assured us that this is not the southernmost site for P. agathiciola. He found it on Roys Rd some 30 years ago - another hunt to relocate I suspect.

A couple of weeks later, on a Rotorua Botanical Society trip to a private land covenant, again P. agathicola was recorded from a site lacking in kauri (grid ref 27649 64042).  This time though, kauri had been felled quite recently in the immediate vicinity (possibly less than 20 years ago) and the find was the result of a deliberate search (although we were beaten to the discovery by other Botsoccers).

Some of these sites have been visited several times in the hope of finding P. brumalis but to no avail. The only site that it has been recorded from is a substantial kauri stand in the Wairoa Stream (grid ref 2762564037).  This is a young stand (perhaps 100 years old) with a dense understorey of kauri grass (Astelia nervosa) and the sweet scented Alseuosmia macrophylla.

We have also eagerly sought Cyrtostylis oblongus and Anzybas rotundifolius but to no avail. The nearest site for these two we know of is Mt William Scenic Reserve (grid ref 2602 64408) near the foot of the Bombay Hills. But there is always hope.