Journal Number 95
May 2005

EDITORIAL

Nematoceras hybrids?
By Ian St George

From a presentation given at Iwitahi 2004.
For the background to this paper see editorial 4, page 9, NZNOJ 2004; 94: 9

1.  Margaret Menzies' photograph (above) and Bruce Irwin's drawing (below) show a Nematoceras
with a round leaf, a broad, short and pointed dorsal sepal, and a flared labellum - characters
intermediate between N. triloba in the broad sense (s.l. = senso lato), and members of the
N. macrantha and N. rivularis groups.

Bruce has suggested it may be a hybrid:  N. iridescens x N. triloba s.l.

2.  Pat Enright and I found a rather similar plant at Lowes Bush in Masterton in October 04,
an intermediate form between N. longipetala and N. hypogaea, both of which were growing
close by.

3.  Gael Donaghy and Graeme Jane found an intermediate form between N. macrantha and
N. orbiculatus, both of which were growing nearby, at Sawcut Gorge in October 1998.

The plant had lateral petals shorter than lateral sepals as in N. macrantha, lateral sepals longer
than those of N orbiculatus, and dorsal sepal wide as in N. orbiculatus but long as in N. macrantha.

4.  Another Pat Enright find from the Tinui Taipos is a curious round-leaved plant with a
labellum like that of N. macrantha, but a dorsal sepal like that of N. triloba s.l.

It appears to be identical to one I found south of the Taipos, on the Putangirua Pinnacles
track in southern Wairarapa one November, among flowering plants of N. macrantha and
N. "Trotters"; could this be a N. macrantha x N. "Trotters" hybrid?

5.  Bruce Irwin sent drawings of a plant he had found at Dicky's Flat in 1991.

He suggested it too is a N. macrantha and N. triloba s.l. hybrid, and indeed it has a flared
labellum and round leaf like those of N. macrantha, but a short and rather bluntly pointed
dorsal sepal.

The other structures of the flower appeared also to be intermediate between those of
N. macrantha and N. triloba s.l., both of which were flowering nearby.

7.  Trevor Lewis sent a photograph of a plant he had found near Nelson.

It looks remarkably like Olaf John's plant, with its trilobate leaf but flared labellum
and short blunt dorsal sepal.

8.  Margaret Menzies and Alan Ducker found a strange Nematoceras near Taumarunui.

It had a long, broad and pointed dorsal sepal, a  tall and narrow labellar shape, rather
reminiscent of N. "rimutaka", and a trilobate leaf.

Again, the suggestion is it is a hybrid between one of the N. triloba agg. and one of the
N. rivularis group.

9.  Bruce Irwin photographed and later drew a plant he found at the Paramanawera wetland:
N. macrantha, N. "rest area", N. "sphagnum" and N. orbiculatus were also present:

Is it a hybrid? What are its parents? Is it the same as the Taumaranui plant?

10.  Eric Scanlen's photographs of round-leaved taxa of Nematoceras aff. triloba with
long and bluntly pointed dorsal sepals, and labella like that of N. hypogaea, taken at Rainbow
Skifield and at Whakapapa, look remarkably similar to each other - and rather like the
Taumarunui and Rangataua plants above.

11.  Is the round-leaved Nematoceras from Horopito a hybrid?

It has a simple short rounded dorsal sepal, like any N. aff. triloba, but it has the round leaf
and the flared labellum of N. macrantha.

If this is a hybrid? in which case are all roundleaved N. aff. triloba hybrids?

Summary

1. There are no proven Nematoceras hybrids - to be proved the hybrid must be reproduced
by artificial cross-pollination.

2. It seems likely however, that some hybrids do exist in the wild - plants with structures
intermediate between supposed parents which both grow nearby, for example:

N. iridescens x N. triloba s.l. round leaf

N. hypogaea x N. longipetala round leaf

N. triloba s.l. x N. "whiskers" trilobate leaf                          } One parent is N. triloba s.l.

N. macrantha x N. triloba s.l. trilobate leaf

N. macrantha x N. "Trotters" round leaf

N. macrantha x N. orbiculatus (hybrids between members of the N. rivularis group and
the N. macrantha agg. will be hard to spot unless structurally intermediate between two
obvious parents nearby).

3. There are some others that have characters between N. triloba s.l. and N. macrantha,
or N. triloba s.l. and N. rivularis agg. which may or may not be nearby, for example
N. aff. triloba "roundleaf" forms from Horopito, Whakapapa, Rainbow skifield.

Acknowledgements
I am grateful to the artist and photographers whose work is reproduced here.