Journal Number 109
August 2008

ORIGINAL PAPERS

Were the Early Botanists Actually Gods?
or Did They, Like You and Me, Sometimes Make Mistakes?
By Bruce Irwin

The first botanists who endeavoured to name and describe New Zealand's flora, worked under conditions which we now would regard as extremely difficult - even intolerable. They undertook a difficult task, made a splendid start, but didn't really finish it. How could they? Their explorations were restricted to scattered parts of the country and communications were so difficult that they virtually worked in isolation. Even so it is hard to understand why the Pterostylis montana complex, now so common, remained unknown until 1949 when Hatch described P. montana in TRSNZ 77.

Surely plants of the P. montana complex must have been collected before 1949? They were. To my knowledge they appear in two North Island herbaria, where they are usually identified as P. graminea. But, you say, "P. montana is very different from P. graminea." So it is, but in those early days P. graminea itself was poorly understood.

For almost 100 years, only two grassy-leaved Pterostylis were fully accepted in New Zealand -
P. banksii and P. graminea. The status of a third taxon, P. australis, has always been doubted and generally it has been considered to be a variety of P. banksii. At that time (as now) the true identity of a species was difficult to establish. Even the author of a species would after a year or two, find it hard to recognise his "child". Type specimens were generally held in overseas herbaria, and popular, illustrated field guides were far in the future.

On the other hand, JD Hooker in his Handbook of the New Zealand flora, had very "conveniently" included a statement that P. graminea was probably a small state of P. banksii. Consequently botanists can scarcely be blamed for concluding that only one grassy-leaved taxon existed: so opted to call it by its "alternative" name - "P. graminea" (the small form of P. banksii).

In November 1886, Edwin B. Dickson found what was almost certainly P. aff. montana at New Plymouth [J50:p.11, J52: p.31]. Dickson was probably unaware of Hooker's careless statement, but was clearly already possessed of some botanical knowledge, so realised that his plant was neither P. banksii nor P. graminea. A drawing and a draft description were forwarded to JD Hooker at Kew. Unfortunately Dickson apparently found no further flowers, so the plant remained nameless for another 83 years.

Strangely, two years before Dickson's find, F Mueller had described a plant from the Chatham Islands as Pterostylis banksii var. silvicultrix. Clearly it was not a variety of P. banksii, so recently was raised to specific status as P. silvicultrix. Its resemblance to P. aff. montana is undeniable, which perhaps explains why in J79, p.11, Angela Abernethy recorded from the Tuku Reserve on Chatham Island, Pterostylis aff. montana, together with P. australis, P. banksii and P. venosa, but very significantly made no mention of P. silvicultrix.

Early in November 2007 I found plants, just beginning to flower, at Rangaiki Reserve on Chatham Island. All open flowers appeared to be Pterostylis aff. montana, though some in bud, when fully developed, would possibly show some of the range of variations noted among Ruapehu colonies. Other small plants may flower as P. graminea.

A booklet published by the Wellington Conservancy of the Department of Conservation (about 2000), Endemic plants of the Chatham Islands, contains a photograph entitled P. banksii var. silvicultrix seemingly identical with the plants I had found and drawn. If this is so, it raises an interesting question: should some or all of the plants we regard as P. aff. montana on mainland
New Zealand, be known henceforth as Pterostylis silvicultrix?

How could such confusion arise?

Very easily it seems. Descriptions of the first few species within a genus were often brief and lacking in diagnostic information. They may have seemed adequate at the time, but when apparently new taxa came to hand and were compared with them, confident identifications proved impossible.

Hooker's original description of Pterostylis graminea was described in Flora II as "short and unsatisfactory". Very possibly flowers of P. aff. montana had been compared with that description and because results were inconclusive, ended up in herbaria as P. graminea. That of course would set a precedent, so that future gatherings of P. aff. montana, would almost confidently be deemed
to be P. graminea.

In J21 p.5, Lucy Moore published a very useful tabulation comparing P. graminea with the plant now named P. agathicola but at that time regarded as variety rubricaulis of P. graminea. This new grassy-leaved Pterostylis described in Cheeseman's 1925 edition of his Manual of the New Zealand flora, because of its only slightly larger flower was being misidentified with P. graminea.

In order to separate P. graminea from all other grassy-leaved Pterostylis, it is essential to have a clear understanding of that plant's diagnostic features. An important difference is that when the P. graminea flower is viewed from the side, the very few nerves on the dorsal sepal are widely spaced (particularly those close to the midrib) and that the white spaces between them are so free of greenish tints that the top of the column is sometimes faintly visible through them. These "windows" are further emphasised by the unusually dark green areas adjacent to them.

The pattern of nerves on P. graminea is quite distinct from that of P. banksii or any other grass-leaved Pterostylis and is confined to that species - or was - until P. cernua was described recently.
I have not seen that new species but indications are that it is remarkably similar to P. graminea and seems to have the same nerve pattern on the dorsal sepal. Strangely, it is said to have affinities with the P. montana group. I venture to suggest that P. cernua is merely a form of P. graminea.

How strange that P. montana remained unknown for too long, whereas perhaps it would be preferable had P. cernua not been found at all.

Left to right: Pterostylis graminea, P. agathicola, P. montana, P. aff. montana