Journal Number 109
August 2008

THE COLUMN

Stegostyla lyallii aggregate - The Gem of Variability
By Eric Scanlen

Stegostyla lyallii had only two rows of disc calli, wrote Sir Joseph Dalton Hooker in 1864 [1] but only
in his phrase, "Other characters as in Caladenia minor" which has only two rows of calli; except for
C. variegata which he hadn't heard about. So what are we to think, when we come across flowers with
four or six rows on the disc and two to eight rows on the midlobe? These occur in a range of sizes,
and climate zones but were all dutifully reported for over a century as plain Caladenia lyallii, by
devotees of the incomparable Hooker who were not about to step out of line.

But Dorothy Cooper broke the spell in her own Newsletter 2:3, June 1982, mentioning big ones on
Swampy Summit, Dunedin. Then Mark Moorhouse, in Newsletter 6, June 1983, dared to suggest that
the 20mm flowers in Big Bush State Forest at 1500-2500 ft. (457-762m), were a different variety
from the low-land taxon, furthermore, a rare, strange pair he found there, were different again.
The rare pair were Stegostyla "minor" (cover J104) rediscovered in 2003 in the Baton Valley by Mark
and his niece, Georgina Upson. Then Ian St George's Swampy Summit flower and Max Gibbs' big and
small ones at Iwitahi, demolished Hooker's one-species spell, in colour, with three distinct taxa, in
their 1990 Natural History and Cultivation book [2].

The Column's Caladenia Imbroglio in the J72, Sep 99, barely mentioned Caladenia [Stegostyla] lyallii,
that southern jewel of stability to northerners, but he had started photographing them at Iwitahi in
December 1993, storing all the slides in the Caladenia lyallii file. However, indexing the Journals,
turned up the heretical reports above triggering a close examination of the file, producing five
baffling Stegostyla heaps, three with albas. That "jewel of stability" changed overnight into the gem
of variability! The more notable forms were announced with others of Mark's, for moral support,
in J78:31 (and centrefold) March 2001.

Since then, a few sweeps south by the Column and others, emails from Kelly Rennell, Graham Dickson,
Mark and Georgina plus mail from Barbara McGann, have had specimens closely scrutinised so that
the heap of five plus three finally grew to eight taxa, three of them with albas and six of them with
marginal calli to the midlobe thus excluding them from being S. lyallii (J63:4). The albas often occur
with their red barred relatives, suggesting that some evolutionary survival advantage favours the
all-whites, possibly for night flying pollinators.

One alba, (S. "subalpine") is dominant at Iwitahi and S. "Iwitahi" has, so far, only white ones in Nelson.
Monowai and Nelson still have other different Stegostyla taxa yet to be properly identified as
mentioned briefly below.

Here, in less than adequate detail are those eight taxa plus their alba-forms, in approximate order of
size so that you, the dedicated student, can lie in the moss and leaf litter, lens in hand and recognise
or dispute the subjects of this earnest attempt to unravel the Stegostyla lyallii aggregate. Do please
let us know exactly what you find.

Stegostyla alpina  (R.S. Rogers) D.L. Jones et M.A. Clem.
One to three, 20-30mm, flowers, 60-250mm tall, carmine or carmine-striped white bud, four rows
of disc calli and stalked marginal calli to the base of the labellum midlobe (Fig 18) The ovary is green,
often with three red sepal ridges and red glanded red hairs. Peduncle is maroon, thick with white hairs,
bracts are brownish green to carmine. Leaf, 40-80 x 5-10mm, olive coloured, lanceolate, 3 ribbed and
concave.

Graham Dickson recorded a colony from 1,000m up on the Old Dunstan Road near Middlemarch on
23 Dec. 2006. The dried or bitten-off leaf tips in Fig. 17 and other images, indicate both the exposure
at this windfarm site and the rabbit/hare population whose deposits carpeted the ground. Fortunately,
the flowers seem unpalatable to the browsers. The orchids were not uncommon amongst invasive
Hieracium pilosella whose ground hugging leaves let this orchid rise above the cover. Tightly
clustered plants hint at vegetative spread; unlike Caladenia.

Mark met this species on Mt Arthur in Nelson (J78:21) but his photo there was S. aff. alpina. He has
found S. alpina 200m above the snowline to 1,600m on Mount Arthur and up the sides of nearby
Gordon's Pyramid. Georgina had another look on 23 Dec 2007 (cover, & Fig.18) at 1,300m below
Mt Arthur Hut and says that the recent series of droughts in Nelson meant that only single flowered
plants appeared in 2007. Ian St George (pers. comm.) knew this orchid from 660m up on the
Pineapple Flagstaff Walk, Dunedin where Lyall collected the S. lyallii specimens for Hooker.

The Column caught a similar colony in an exposed, mossy ridge top in the Aorangi's at 650m up,
on 27 Nov 2004 and tagged it S. subalpine" (J94:33,36) but, upon close examination it's three
flowers, and other characters as in Fig. 19, from a single flowered one, shows it to be S. alpina.

Fig. 17. Graham Dickson's Stegostyla alpina 23 Dec 2006, at 1,000m altitude near Middlemarch. A tight cluster of plants suggests vegetative spread but note that two flowers and a red bud are all on one stem. Dry leaf ends are due to exposure at this windfarm site.		Fig. 18. Stegostyla alpina 23 Dec 2007 by Georgina Upson at 1,300m up on Mt Arthur, Nelson single flowered due to drought but with its carmine tepal outers, 225° midlobe curl, green ovary w. red sepal ridges, green to red bract and red peduncle. See also the Cover photo.

Stegostyla aff. alpina
One or two, 19-27mm flowers with broad tepals. First recorded by Dorothy Cooper from Swampy
Summit, (739m) Dunedin, Newsletter 2, June 1982, tag named by Ian St George in J63:6, after the
similar Tasmania, S. alpina.

S. aff. alpina has an off-white bud and 3-5 stalked, marginal calli to the midlobe base. (Fig. 20)
The midlobe recurves to 225°, the four rows of disc calli on the top flower and the six on the lower
flower, continue down the midlobe with a jumble of extras near the tip. Inside, the column is mostly
dark red with irregular white bars.

The labellum is red barred with no reports yet of an alba-form. A 105mm, 3 ribbed leaf which was
measured had sparse, long, fine, white hairs like gossamer. The peduncle is maroon but pedicels,
ovaries and bracts are green, differing here from S. alpina.

Found especially on track-sides around the 900m mark, five veined, broad tepals, alpine to subalpine,
South Island, habitat, down to 400m at Waianakarua Reserve, Herbert but with shortish marginal calli
here and down to 250m at Baton Valley. Notably, in twin flowered plants, the top flower has four rows
of disc calli and the lower has six. (Mt Robert {J78:21}, Arthurs Pass and St Arnaud {J88:18} and
Herbert {pers. comm. Barbara McGann}).

Whether the four-row flower later develop six rows is still not known. Flowering time 20 Nov-23 December.

Fig. 19. Stegostyla alpina 27 Nov 2004, labellum on a single flowered specimen in the Aorangi's colony. Note the discrete four rows of disc calli continuing down the midlobe; three marginal calli.		Fig. 20. Stegostyla aff. alpina, a six row flower at Arthurs Pass on 7 Dec 2002, sitting on its own leaf with those gossamer fine hairs. Note the contoured lateral sepals which thus maintain stiffness and shape. The marginal calli to the midlobe, curled under, typical of the genus, and the jumble of midlobe calli typical of the taxon.

Stegostyla "subalpine"
One or two, 15-21mm flowers, ±156mm tall with a ±150mm red/green leaf, first reported in 1990
[2] by Max Gibbs at Iwitahi and tag named by the Column for its marginal calli to the labellum midlobe.

Smaller than S. aff. alpina and restricted so far, to subalpine Iwitahi. In Fig. 21, tepals are not as broad
as some; dorsal sepal is minutely acuminate with only four rows of calli down the labellum disc,
increasing briefly to six by the midlobe base.

Some specimens have four discrete rows; shades of S. aff. alpina? Note, two stalked, marginal calli
at the junction of side lobe and midlobes. Most lack the red-bars inside the labellum and column
as in Fig. E, but retaining the red peduncle to demonstrate that these are not just anthocyanin lacking
freaks. Column wings are white and pendant. Sparse stipitate red glands, adorning the dorsal sepal
and inside the base of the lateral sepals, are especially notable on the albas. Flowering time, 27 Nov
to 9 Dec.

Stegostyla lyallii "4 row"
One or two, 17-21mm wide flowers, Fig. 22, five veined broad tepals and only sessile marginal calli
on the midlobe with four rows of disc calli changing to four double rows in a jumble on the midlobe.

Variable markings inside the column, from almost solid dark red to alternate red "leaves" lying either
side of a white centre strip. Dark red bars to the white labellum side lobes, begin well back from the
leading margin. Georgina has this as common in Nelson; so no doubt nobody bothers with it.

The Column's only colony, at 660m on Brunner Peninsula, St Arnaud, had one of the plants flowering
21 days ahead of S. aff. alpina growing in almost the identical spot. No alba forms were present.
Flowering time, 29 November.

Fig. 21. Stegostyla "subalpine", the predominant alba form with dark red peduncle just coming into view. The acuminate dorsal sepal has those stipitate red glands. Bits of Pinus nigra needles, keep the flower open to view. Four rows of calli increasing to six at the front on this specimen. Others have only four rows.		Fig. 22. Stegostyla lyallii "4 row" from St Arnaud, 29 Nov 2002. It has red barred labella, visible only to the pollinators unless wedged open. Out of sight are four rows of disc calli. Note four double rows of calli crowd atop a midlobe lacking marginal calli. Also, crowds of larvae-repellent hairs crowned with red glands on the ovary.

Stegostyla "lytuck"
Solitary, 19-21mm wide flowers, subalpine with no alba form. Green ovary, pedicel and peduncle.
Bud is off-white but the dorsal sepal at the Aorangi's had crowded stipitate red glands. Noticed by
the Column at Iwitahi (on film, after the event) and on site on Mill Track in the Aorangi's.

The translucent lobes of the upper column wings, are folded symmetrically at right angles across
the front of the column as in Fig. 23. Four rows only of disc and of midlobe calli, four marginal
calli at the junction of midlobe and side-lobe. S. "subalpine" is similar except for its differing
column wings, alba-form, midlobe & marginal calli numbers and extra half rows of disc calli a
t times. Flowering time, 27 November to 13 December.

Stegostyla "minor"
One or two, 18-20mm wide flowers with narrow tepals. Mark's tag and his find of 1982 and 2003
et sec., announced and depicted in J95:15,16,31; 101:26,31; 104:1; 107:18. It has been too
rare to take specimens for molecular checks as yet. The 1982 site has been afforested so the Baton
Valley, some 40km away, remains its only know habitat at this time with two known colonies, 1.6km
apart.

The narrow dorsal sepal, is atypical of S. aff. lyallii agg, as are only two rows of disc and, midlobe
calli, the latter, small and pale so easy to miss in a photo. The midlobe has five, long, marginal, calli
Fig. 24, at the base, progressively shortening towards the acute tip which recurves 270°. The above
characters may align S. minor more with the smaller S. atradenia than with S. lyallii agg.

However, red sepal ribs on a green ovary are reminiscent of S. alpina or the red stemmed Caladenia
(Petalochilus) minor (was C. aff. chlorostyla). Red midribs on the tepal outers make it almost as red
in bud as S. alpina. Altitude range, 200-650m, flowering in the last two weeks of November.

Fig. 23. Stegostyla "lytuck" 13 Dec 1997 Iwitahi. Lower column wings, folded square across front of column, are partly obscured by the anther. Four marginal calli; one from the side lobe, three from the midlobe but one is missing on the left. Note the dumpy little anther connective typical of all Stegostyla.		Fig. 24. Stegostyla "minor" by Georgina Upson from Baton Valley showing the very long marginal calli and the tightly curled midlobe. Check the cover of J104 for a frontal view of this same flower with its unique midlobe calli in only two rows. The rarity of this orchid has prevented specimens being taken for scientific evaluation.

Stegostyla lyallii  (Hook f.) D.L. Jones et M.A. Clem.
Solitary flower ±18mm wide with narrow lateral tepals and minutely acuminate dorsal sepal adorned
with red glanded white hairs. Only two rows of disc calli (with perhaps a few strays) but four rows on
the midlobe; has not been easy to find in the north and is unusual amid the S. lyallii "4row" taxon in
Nelson. The Column has one only alba-form, Fig. 25 from Iwitahi and one possible red barred
specimen from Ketetahi Track. Mark has red barred ones (J78:Plate 1, Fig. 4) from Mt Robert. Nelson.

The alba has two stray marginal calli on only one side of the midlobe base. David Jones's drawing [3]
from specimens sent from NZ by Dr. Brian Molloy (J61:8; 63:4).shows the two rows and only sessile
calli on the margin. Flowering time, early December in the North Island

Stegostyla "Iwitahi"
Single, ±18mm wide flowers, ±150 tall, went for years under Ian St George's S. aff. lyallii label in
J46:2, see J76:39 for this small one and Fig. 26. But "affinis" applies to any taxon like the named
species so Georgina, who first spotted it away from Iwitahi at her Baton Valley place, recently
proposed S. "Iwitahi", with no objections to date. Notably, her Nelson ones (Fig. 27) are so far,
all greenish albas but with copious red glanded hairs on the green ovary plus a dark, near black leaf.

Thus these too cannot be freaks lacking anthocyanin. This smallest S. lyallii agg, was common at
Iwitahi hence shunned by photographers who favoured its more spectacular big brothers. Four
rows of disc calli [J63:5; 76:39] continue down the midlobe but not onto the tip. It has narrow,
three veined tepals and an acute, sometimes gable ended dorsal sepal contrasting with the umbrella-
like affairs on most. The definitive midlobe is an equilateral triangular (J63:5 Fig. 3) with drop-side
margins and tip. Two marginal calli decorate each forward side-lobe base. Flowering, early December
at Iwitahi; early January in Nelson.

Fig. 25. Stegostyla lyallii Hook. f. Iwitahi, 8 Dec 2000, the alba form, lacking red bars in labellum and column but with normal red pedicel and peduncle indicating that this is no anthocyanin lacking freak. Two rows of disc calli as indicated by Hooker, but extra small midlobe calli extending back onto the disc. Note minutely acuminate dorsal sepal adorned with stipitate red glands.		Fig. 26. Stegostyla "Iwitahi" (was S. aff. lyallii) the red barred form of our smallest S. lyallii agg flower from Iwitahi, 2 Dec 1994 has that long enclosing dorsal sepal and the labellum midlobe with the drop-sides and tip; no calli atop the tip. Two short, marginal calli to the base of the midlobe.

		Fig. 27. Stegostyla "Iwitahi alba" by Georgina Upson from Baton Valley showing the unique drop-sides and tip to the labellum midlobe. Note the red glands to the ovary and red margin to the bract. No lack of anthocyanin here. Baton Valley plants are alba-forms, suggesting that these plants have evolved thus for a reason.

Four further taxa at least, are still in the wings including:-

1. A specimen of Mark's S. aff. alpina (J78:23) which grew two extra outer rows on the six row, unpollinated flower, within a week of it opening but the upper, four row flower, had been pollinated and faded.
2. Kelly's S. aff. alpina at only 170m altitude near Monowai, one specimen (J90:26) with a red midlobe
3. Mark's "small one" with broad tepals and a naked pink midlobe dropping straight down.
4. Mark's S. "Mt Robert (J78:bottom of page facing 26) and S. "Sherry River" (J107:18) may be
   the one taxon. More extended observations are sorely needed for these intriguing taxa.

Footnote
David Jones et al, proposed the Stegostyla genus [4] which seemed logical considering the chromosome count 2n=48 which makes fertile hybrids highly unlikely with Caladenia (Petalochilus), 2n=38, despite being close on the phylogenetic tree [4, p417]. However, Hopper & Brown [5] disputed this and would have sunk Stegostyla to sub-genus ignominy.

However, look at their definitive morphological differences (Caladenia in brackets) which include;
calli on top of the midlobe (none to speak of), umbrella-like hooded dorsal sepal (narrow, flattish
and usually upright), tepals are white inside, rarely with a red spot or two (greenish and pink, one
alba form), larger flowers, 18-25mm across (8-20mm).connective to the anthers, obtuse short
and papillose (acute, long, entire), 2-8 rows of disc calli (two regular rows, except one with scattered strays) but both genera have a cluster of 4-6 large calli by the column. The Column upholds
Stegostyla as a distinct genus because the separation between the two genera is apparently
complete, both morphologically and in chromosome counts.

Acknowledgements
Many thanks to Barbara McGann for information about Waianakarua Reserve specimens, Kelly Rennell for the Southland taxon, Mark Moorhouse and Georgina Upson for information and critical analyses of taxa around Nelson, especially S. alpina, S. "minor" and S. "Iwitahi alba", to Graham Dickson for bringing home the fact that we do seem to have S. alpina in NZ, to Ian St George and Dot Cooper for their ground breaking early work and to all the many contributors for their patience with the Column's harangues about Stegostyla.

References
1. Hooker, J.D. Handbook of the New Zealand Flora. 1864
2. St George. I.M. McCrae, D, New Zealand Orchids, Natural History and Cultivation NZNOG 1990
3. Jones, D.L. Reinstatement of Caladenia alpina R.S. Rogers (Orchidaceae) as distinct from C. lyallii
4. Hook. f. and the description of C. cracens, a related new species from Tasmania. Muellaria 9: 41-50.
5. Jones, D.L. Clements, M.A. Sharma, I.K. Mackenzie, A.M. A new Classification of Caladenia R.Br. (Orchidaceae),     Orchadian, Vol. 13, No. 9, September 2001, 393-417
6. Hopper, S.D. Brown, A.P. Robert Brown's Caladenia revisited, including a revisit of its sister genera Cyanicula,     Ericksonella and Pheladenia (Caladeniinae: Orchidaceae) Australian Systematic Botany 17:171-240