Journal Number 95
May 2005

NOTES etc

For Lack of a Moth, The Orchid is Lost
From US Fish & Wildlife Service Feature Series, Vol II No. 4.

The western prairie fringed orchid stands as one of the gems of North America's remaining tallgrass prairies. This flowering orchid may grow to 4 feet tall, comparable in height to the surrounding prairie grasses, and may have up to two dozen white to creamy white fringed flowers.

Curiously, the regal appearance of this plant does not attract insects to pollinate the plant during the daylight. Rather, as night descends over the prairie, the orchid's flowers increase its fragrance to attract the roaming moths. Shrouded in this cover of darkness, the long-tongued hawkmoth rises to visit the intoxicating flowers.

"Ironically," notes Kathy Martin, a botanist with the U.S. Fish and Wildlife Service in Bismarck, North Dakota, "this moth is unremarkable in appearance and coloration. What's unusual about it is its uniquely evolved tongue for harvesting the orchid's nectar. The orchid's white fringed petals direct approaching moths to the spur and the plentiful supply of nectar it holds." As the moth hovers with its long tongue extended into the spur, two specialized pollen-bearing structures brush pollen onto the eyes of the moth.

The western prairie fringed orchid nectar spur is the longest of any North American orchid. Only those species of hawkmoths with suitable length tongues and properly spaced eyes can act as pollinators.

After attaching to the eyes, the pollen may be deposited upon the next orchid flower the moth visits. This transfer of pollen among orchids results in fertilization and ultimately the production of seeds.

The remarkable relationship between the long-tongued hawkmoth and western prairie fringed orchid has been continuing successfully for centuries until European settlers settled the heartland of North America. "They found the tallgrass prairie yielded fertile soils, ideal for raising a variety of crops," said Martin. "Millions of acres of America's prairies were rapidly converted for cropland. Today we have only about two percent left of the tallgrass prairie and less than 40 percent of the original western prairie fringed orchid populations."

Today, tallgrass prairie has generally been reduced to small islands in a sea of cropland, and the orchid, facing potential extinction, was listed as a threatened species under the Endangered Species Act in 1989.

The fragmented prairie landscape created by man poses the greatest obstacle for these insect-oriented orchids. The expanses of cropland act as a barrier for free movement of hawkmoths between different orchid populations, reducing genetic diversity of isolated stands. Pesticide drift from nearby cropland also poses a threat to non-targeted insects such as the hawkmoth. In some areas, hawkmoth numbers are so depleted that only a very small percentage of flowers are pollinated and produce seed.

These remaining tallgrass prairie tracts must also be intensively managed to prevent native trees and shrubs from invading and shading orchids out, or by exotic weeds such as leafy spurge that can displace the orchid and other native prairie vegetation.

Approximately a quarter of known western prairie fringed orchid sites are protected in preserves or other publicly-managed areas. Land managers are concentrating their efforts on meeting the orchid's needs through implementing long-term management plans.

Providing hawkmoth "corridors" of native prairie between orchid populations could offset the immediate threat that faces isolated populations. However, some orchid preserves are isolated tens or even hundreds of miles apart. For these secluded populations, pollinating the plants by hand can buy the orchid some time until their prairie habitats can be rejoined and pollination can be reclaimed by its original masters.

Long-term survival of this tallgrass prairie gem requires not only protecting its habitat but also insuring the survival of the orchid's only means of reproduction, the long-tongued hawkmoth.

Gordon Sylvester wrote (2 February), "Urgent widening works are to be carried out on a
two or three kilometre stretch of road. 'What's so important about this?' I hear you ask. To be more specific it is the stretch of provincial highway that has the honour to be the Type locality for Pterostylis cernua at culvert 53.

"It was brought to the attention of the local DoC, and botanist Phil Knightbridge did a brief survey along with other DoC officers. They decided to approach Transit NZ to attempt to relocate a specimen sized population to a similar location and to reseed the site when all was finished and the habitat has regenerated.

"Accordingly two DoC personnel and a Society member recorded and moved about 40 plants to a secure location nearby.

"During the collection another Pterostylis reared its head. It hadn't been spotted previously. but is thought to be P. aff. montana as this is also present in the area along with P. irsoniana.

"While moving the plants an opportunity presented itself to discuss how this particular species came to be in this specific location, whereas it is normally found in Manuka sphagnum moss areas. Here it is podocarp kahikatea forest along the side of the roadside drain, invariably on the side away from the roadside and in areas where the Blechnum fern is not present; it likes full sun and air movement. The best guess is that it is adventive, migrating down the drain from the manuka association at the top of the hill.

A careful search was made and there were no plants below a certain point in the length of the road. A search is to made above the Type locality to determine this population, if it does exist, before the road works overtake the search. We will keep all posted about the progress of this project."

Phil Norton of Blenheim wrote that they "ventured far and wide over the South Island; Christcurch, Oamaru, Naseby, Bealey, Karamea - eventually walking the Heaphy Track before returning home. The weather could have been a lot worse. Naturally I always have my head down looking for orchids and have been rewarded with some good (for me anyway) finds some of which I think I have identified; others I hope that you may be able to help me with".

Of the pictures attached, Fig.16 and Fig.17 I found in the bog on the saddle at Arthurs Pass. Fig.16 appears to me to be Aporostylis bifolia - which would fit its location. Fig.17 I think is Caladenia lyallii - it is quite big (about 30mm).   (Editors identifications in small print)

 
Aporostylis bifolia                           Caladenia lyallii

Fig.18 I found a lot of around the Saxon Hut on the Heaphy, I think this is Pterostylis humilis
or venosa (I think venosa) judging by the three leaves.

Pterostylis venosa

The remainder I found in an afternoon at the Perry Saddle in open herb fields and light scrub.
Fig.19 had me puzzled until I realized it was not a Microtis but a Prasophyllum of some sort.
It looks a bit like P. colensoi but the flower parts are smaller than the picture on the web site.

Prasophyllum colensoi

Fig.20 I don't have a clue.

Unidentified plant, resembling Waireia,
but with a very strange dorsal sepal - Ed

Fig.4 looks like the Aporostylis bifolia I found at Arthurs Pass but it is bigger and has extra larger dark red-brown spots on the labellum. It does have the two odd sized mottled leaves though.

 
Aporostylis bifolia

Fig.21 would appear to be Waireia stenopetala, I found quite a few of these at the base of the slope in mossy wetter areas.

 
Waireia stenopetala

I also saw many Pterostylis (some magnificent banksii) and a stunning Gastrodia which I didn't photograph (it was raining).

No orchids in the Naseby forest which disappointed me - maybe one day they will establish there.

Bob Bates reported [NOSSA Journal 2004; 28 (11): 113] that there are still ten unnamed taxa of Thelymitra in South Australia; that "news is gradually coming through that many SA leek orchids of the Prasophyllum odoratum alliance … are now being worked on and there could be as many as a dozen of these in SA"; and that there are still almost a hundred unnamed species waiting to be written up. "Not only are we lucky enough to be living in a time when so many things can be discovered but we will also be the last people to see many of them before they disappear forever". It's a sobering thought-Ed.

In the same issue Bob lists a dozen good orchid sites in the Clare Valley-one of SA's best wine-growing regions. We could do the same for Marlborough, south Wairarapa, Hawkes Bay, Poverty Bay and a few other producers of those health-giving beverages.

Tracey and Bernard wrote from Queenstown, "These photos were taken up on the east side of the Mt Crichton loop track at twelve mile creek Queenstown. We had been keeping a close eye on the orchids in this area and were disappointed a couple of weeks ago when someone maintaining the track went and cut quite a lot down on the side of the track with a trimmer.

We are waiting for a paler colour to flower but don't think it is going to happen this year."
The photographs were of Microtis unifolia, Prasophyllum colensoi, Pterostylis australis (below right), Thelymitra pulchella with a large labellum (below centre), and Thelymitra cyanea (below left).

Mark Moorhouse wrote, "Your article [J94] on hybrids is excellent and clearly lays it all out. Thanks for the enlightenment. In the light of this and the picture on p25 of the artificial hybrid P. banksii x irsoniana, I think I have a solution to a mystery Pterostylis on Arapawa Island (Fig.23). It would seem likely that it is a natural hybrid between P. irsoniana and P. montana.

Also present within a half mile radius are P. banksii and P. graminea, both of which are less likely parents due to the flowering time of 19 December. P. graminea is present there in numbers, P. montana and P. banksii much less so. It has clearly a P. irsoniana labellum with basal callus but otherwise the galea could be P. montana. Comments please."

A letter in reply to Omoc: "On pages 7-8 of J93, the editor explained his very sound reasons for including articles on alien orchids and very cleverly informed a critic that 'it is not the journal of NZ native orchids, but the NZ journal of native orchids, so any country's native orchids are fair subjects.' I thought those very reasonable explanations would end the matter. They did not.

"Omoc (one member or critic) overflowed a complete page in J94 listing specious reasons for his complaints. How dare he thus deprive readers of valuable space for articles on native orchids, NZ or alien?

"Omoc says he must remain anonymous. Why then did he leave two full columns of evidence, leading inexorably to his identity?

Amoc (another member or critic)."

Pat Enright, Featherston, wrote, "There is a very nice area of bush in the eastern Wairarapa that has yielded a few botanical surprises. When I asked permission to survey the area I was told that it was 'mainly kanuka' and the implication was of not a lot of interest. It is mainly kanuka but has a fascinating collection of other species growing underneath. Including ferns, herbaceous species and at least one tree species of note.

"Included in this assemblage is Gastrodia 'long column'. There are two entities present in differing ecological niches. In the drier kanuka scrub there is a black version of the taxon and in the wetter more sheltered areas a yellow version is to be found. Eric has determined that there is at least one difference in the specimens I sent to him being a variance in the shape of pseudo-pollen ridges under the labellum. Further expert opinion may be forthcoming but it seems that it currently leans towards colour morphs of the same thing.

"I have seen a lot of the yellow flowered entity on the wetter slopes of the Tinui taipos but no sign of the black version in the same area.

"There is a very small window of opportunity to get flowering specimens of Gastrodia in the Eastern Wairarapa as the generally hot dry weather around flowering time ensures a rapid 'flower to seed' advance. The areas where the gastrodias can be found are quite a distance apart and few in number and the number of plants in any one area is usually small. Most areas where gastrodias are found have a fair degree of moisture available either by virtue of a nearby stream or hilltops under tall timber where more shelter and mist are available. The black entity may be an adaptation to a drier area but this is purely speculative and I would appreciate comments from other observers.

"I will be going back to the area this spring to check out  the rest of the orchid flora which was pretty much toast by the time I got started on the survey.

"A plug for what are regarded by many people as 'firewood lots' is in order. Kanuka stands can be areas of intense botanical interest as the above example shows and should be protected wherever possible. They act as nursery areas for other tree species and can be great places to botanise in the orchid season. Who knows what has been lost in the past through clearance of kanuka blocks?"

Tuvalu doesn't have Thelymitra venosa any more than it has T. cyanea (which this appears to be), but it does have a thriving industry in postage stamps, and a world-wide following of dedicated philatelists who collect the product. Jennifer Toombs (look her up on the internet) is a stamp designer, lives in Britain, but has designed stamps for many countries.

In The Orchadian this month, Michael Harrison writes about "Twig epiphytes of Australia", including a photograph of cousin Drymoanthus minutus. It grows on the outermost twigs of rainforest trees in north Queensland, north of Townsville south to Cairns. It is often seen within accumulations of broken twigs and mosses that hang from lower tree branches. Invariably it grows in wet forest, often near creeks and rivers, usually in heavy shade. The leaves are rarely more than 20 x 5mm, and the inflorescence bears 7-8 flowers which are 3mm tall, green with a fleshy white labellum. It flowers in summer.

4th Native Orchid Conference 9-12 July 2005, St Benedict's Retreat & Conference Center, Winnipeg, Manitoba, Canada: organised by the Native Orchid Conference Inc, a web-based forum whose aim is to "foster the study, conservation, and enjoyment of the native orchids of the United States and Canada". Go to http://groups.yahoo.com/group/NativeOrchidConference/

3rd International Orchid Conservation Congress ?16-23 March 2007, simultaneously with the 2nd International Conference on Neotropical Orchidology, San José, Costa Rica. Organised by Jardín Botánico Lankester (also the host), Universidad de Costa Rica, Charles H Lankester Foundation, and the Orchid Specialist Group. Provisional details are available online in the OSG's newsletter, Orchid Conservation News (OCN), Issue 5, pages 24-27.

19th World Orchid Conference February-March 2008 Miami Beach, Florida, USA: hosted by Fort Lauderdale and South Florida Orchid Societies. Includes, as always, a comprehensive lecture programme.