Journal Number 109
August 2008

Notes etc

Mike Lusk saw Caladenia's in Boundary Stream reserve on Jan 8, and another from
Kuripapango Hill in the Southern Kaweka's on Feb 22 at 1350m. Very late, as he pointed out,
and rather unusual, as Eric Scanlen pointed out.

Now here's an interesting paper by Anne Gaskett and her colleagues in Australia:

ABSTRACT: Sexually deceptive orchids lure pollinators by mimicking female insects.

"Male insects fooled into gripping or copulating with orchids unwittingly transfer the pollinia.
The effect of deception on pollinators has been considered negligible, but we show that pollinators may suffer considerable costs. Insects pollinating Australian tongue orchids (Cryptostylis species) frequently ejaculate and waste copious sperm.

The costs of sperm wastage could select for pollinator avoidance of orchids, thereby driving and maintaining sexual deception via antagonistic co-evolution or an arms race between pollinator learning and escalating orchid mimicry.

However, we also show that orchid species provoking such extreme pollinator behaviour have the highest pollination success. How can deception persist, given the costs to pollinators?

Sexually-deceptive-orchid pollinators are almost exclusively solitary and haplodiploid species. Therefore, female insects deprived of matings by orchid deception could still produce male offspring, which may even enhance orchid pollination."

[A. C. Gaskett, C. G. Winnick, M. E. Herberstein (2008) Orchid Sexual Deceit Provokes Ejaculation.
The American Naturalist 171: 6, E206-E212. http://www.journals.uchicago.edu/doi/abs/10.1086/587532].

Go to http://www.anbg.gov.au/cpbr/cd-keys/orchidkey/html/AustralianOrchidNameIndex.pdf
for the new Australian orchid names.

The June issue of The Orchadian has a paper by David Jones, in which he gives notice of his imminent new book on the orchids of the ACT, for which he describes twelve new orchids in this paper - including a new Stegastyla (S. moschata), Calochilus platychilus, Corunastylis cornuta, Spiranthes alticola, and others in genera unrepresented in New Zealand.

Of the Spiranthes, he says that S. australis is no longer considered a single entity, but contains at least 3 taxa, one of which is the new species - with a flaring (rather than tubular) labellum (Jones DL, 2008. Twelve new species of Orchidaceae from south-eastern Australia. The Orchadian; 15 (12): 546-558). In a second paper (ibid, 559-561) he and Dean T Rouse describe two new species of Prasophyllum from the ACT.

Kevin Matthews sent a reprint of a paper describing colonisation of pine stumps by the fungus Armillaria [1]. The paper noted, "Rhizomes of the native orchid Gastrodia cunninghamii were found associated with some stumps, and are common in Kaingaroa Forest, sometimes in large quantities, among roots of pines infected by A. novae-zelandiae.

Armillaria rhizomorphs occasionally ramify across the surface of orchid rhizomes (personal observation), but mycorrhizal infection as reported in Nothofagus forest in the South Island (Campbell, 1962) has not been confirmed. It therefore remains to be determined if the distribution of the orchid in pine stands is related to the occurrence of A. novae-zelandiae."

The late Ella Campbell had found the mycorrhiza of Gastrodia cunninghamii to be Armillaria mellea [2].

Kevin pointed out that the two species A. novae-zelandiae and A. limonea were collectively called Armillaria mellea in old records. He sent the beautiful photograph of Armillaria limonea sym Armillaria mellea shown in Fig.1, inside front cover.

1. Hood IA, Gardner JF. Colonisation of Pinus radiata thinning stumps by Armillaria and other Basidiomycetes     following treatment with Armillaria basidiospores. 2008. New Zealand Forest Research Institute, Rotorua.
2. Campbell EO, 1962. The mycorrhiza of Gastrodia cunninghamii Hook. f. Transactions of the Royal Society of
    New Zealand, Botany 1: 289-296.

Kevin Matthews sent the photograph of 70+ flowers on a tuft of Adelopetalum tuberculatum,
from near West Foley's Bush, Northland, taken 1 June 2008.

Eric Scanlen wrote, "AD Mead lists Corybas unguiculatus (Anzybas rotundifolius) in the Waitakeres in his 1972 second edition of Native flora of the Waitakere range, Auckland.
I came across it whilst hunting for something else.

Peter de Lange also told me that there were specimens of it in AK from the Waitakeres: I guess Arthur Mead would have deposited the specimens. Thus there is tangible evidence that it once resided further south than Warkworth. Arthur was Waterworks Engineer for the Auckland City Council when the Waitakeres were the sole source of water for Auckland. He was also a dedicated conservationist so he knew the catchment areas inside out."

Eric Scanlen noticed that eastern Victoria had both Thelymitra decora and T. pulchella. But how
did our endemic orchids* go against the prevailing wind to Victoria? Kevin Matthews said birds, insects - including butterflies (J108:2,4) - were suitable carriers. Kevin showed evidence that dotterels from lower South Island migrate to coastal Victoria during Dec-March, just when the orchids would be dehiscing.

But hold on: both those Thelymitra from Victoria have recently been reclassified.

Their T. decora is now T. simulata and has only 2n=52 chromosomes (our T. nervosa/decora has 2n=54). Furthermore the Aussie T. pulchella, (which is a dead ringer for one of the many forms of the NZ T. pulchella), has also been reclassified as T. erosa, said to be uncommon and only in the subalpine zone so there is the problem of how the dotterels, frequenting coastal Victoria, ever got the seed up there.

There now being no NZ endemic orchids naturally occurring in Australia, Eric has returned to championing the jet-stream theory for orchid seed transport - because the jet stream moves only eastwards as do the orchid seeds. Butterflies and other insects still hover as possibilities because they probably only move eastwards, like the orchid seed, with the prevailing wind. But could the seed survive the 50-60 hours' transit time in the desiccating warmth at sea level? For that matter, could orchid seed survive in the extreme cold of the jet-stream at ±10km up? Volunteers please, to fly up and sieve the jet-stream for orchid seed.

* Neither Thelymitra decora nor T. pulchella could have originated in Australia because they are amphidiploid  hybrids with NZ endemic Thelymitra longifolia as one parent. So progeny of
T. longifolia (T. decora and  T. pulchella) could not arise in Australia without a westwards carrier
of some sort.