Journal Number 109
August 2008

ORIGINAL PAPERS

Nematoceras "whiskers" Variation in the Nelson Region
By Georgina Upson

As a keen amateur botanist I have great difficulty defining the plant described in manuscript
by H.B. Mathews as "Corysanthes viridis" and today bearing the tag N. "whiskers".

During 2006, a preliminary investigation into N. "whiskers" variability in the Nelson area had
interesting results. This season's inclement weather, bringing floods, left me frustrated,
searching for more widespread colonies to study and a few more tantalizing finds.

There are two sites that I have spent the majority of my time in. One site is in the hills to the
east, the other to the west of the Waimea plains. A brief skirmish to the Tinline area added
an extra dimension.

The Eastern site is a damp, exposed rock outcrop dropping into a river. Little direct sunlight
with no overhanging vegetation leaves the area with a comparatively high light level.

Vegetation is largely mosses and creeping plants. Both N. "whiskers" and N. orbiculatum
are present.

The western site consists of rock shelves jutting into a large stream with dappled shading
from overhead trees. Mosses and creeping plants also form the vegetation here.

Only N. "whiskers" is present but N. acuminatum is to be found nearby. 100mm of rainfall
in one hour proved, to my dismay, just how precarious these abodes are by scouring most
plants and support vegetation from their rocky perch.

The vast majority of N. "whiskers" will fit into a reasonably standard shape and colour pattern
in this area. Some colonies are homogeneous, perhaps due to single seed genesis and
vegetative expansion. It is mainly on these rock outcrops that a small fraction of plants
have developed an adventurous streak.

The labellums of some differ markedly from the norm, while still maintaining the "standard"
colouration. Fig. 2 Standard; The most common shape found in N. "whiskers".

It is more or less diamond shaped with varying degrees of roundness to the apex of the
labellum which can occasionally have a small apiculus. Fig. 3 long; the labellum and lobes
are elongated. This can give a long narrow opening to the interior. The lobes protrude
further forward from the labellum disc.

Fig. 4 N. "Kaimai"-like; these have a longer more rounded appearance than the standard.
The disc narrowing evenly to the apex sometimes has a small apiculus. Fig. 5 circular;
these labellums take an almost round form. The labellum disc is flat. It seems unreasonable
to classify these as anything other than N. "whiskers" given that intermediate forms are to
be found.

Fig. 2: Standard - The most common shape.		Fig. 3: Long - The labellum and lobes are elongated.
Fig. 4: Nematoceras "Kaimai"-like.		Fig. 5: Circular - These labellums take an almost round form.

The situation becomes more complex (and interesting) when one considers the plants that
have colouration outside the N. "whiskers" norm. Almost colourless translucent flowers occur
in the darkest sites. In higher light the variation in colour and pattern increase noticeably.

Perhaps this is due to the higher percentage of flowering plants increasing the potential for
cross pollination and/ or a response to the light level. The difference in habitat may also
promote change in some.

Green flowers similar in colour to N. papa, others indistinguishable from N. "Kaimai", and
N. "Tinline" are to be found. Fig. 6: N. dienemum, N. longipetalum or N. "Pollok" hints of
all three. Fig. 7; red or red/ black lobes are almost a feature of this long shape.

Fig. 8; almost reverse N. "Pollok" are to be found that have a green strip down the centre
of the labellum, the remainder of the flower crimson. These extremes "shade" back into the
standard flowers with intermediate examples, see Fig. 9.

Fig. 6: N. dienemum, N. longipetalum or N. "Pollok" hints of all three.		Fig. 7: Red or red/ black lobes are almost a feature of this long shape.
Fig. 8: Almost reverse N. "Pollok" are to be found that have a green strip down the centre of the labellum, the remainder of the flower crimson.		Fig. 9: Extremes "shade" back into the standard flowers with intermediate examples.

There appear to be trends between labellum shape and colour, but to make matters worse
some plants simply mix and match. As all these combinations lead to N. "whiskers" or diverge
in differing directions, whichever way it is viewed, it becomes difficult, to say the least, to place
any definite boundary between N. "whiskers" and other taxa. There are differences between the
sites that may suggest an east to west drift.

With the differences in labellum shape already seen in normally coloured plants are the other
differences simply colour variations and these still essentially N. "whiskers", but only just?
Are Nematoceras "whiskers" capable of considerable genetic gymnastics!

Alternatively are the long lobed plants in fact a precursor to, or reversion of N. "whiskers" and
is it these interacting, or not, with N. "whiskers" that are generating these variations?
There are many questions.

These variants have survived to a mature stage indicating potential to form colonies either
sexually or vegetatively. That no colonies have been found as yet may indicate they are of
recent origin, they may be sterile, the ecological niche is high risk or simply insufficient
investigation has been carried out to date.

With a number of variants living in close proximity to one another there must be a reasonably
high potential for them to cross pollinate. At what point should one decide that a new species
has been found?

Acknowledgement
Thanks must go to Eric Scanlen for providing me with information on the phylogenetic tree and photographs
of North Island taxa. Also for informing this absolute amateur on how to format etc an article and putting
forward a challenge to write something.