The terrestrial genus Adenochilus contains only two species. The Type species, A. gracilis JD Hook., was described in 1853 and is endemic to the South Island of New Zealand and Stewart Island. The Australian member, A. nortonii, was described by Robert D FitzGerald in his Australian orchids in 1876.

From the NZNOG Journal #62 on Adenochilus nortonii:
This dainty orchid was first brought to the attention of Robert David FitzGerald by one of his botanical friends, a Mr James Norton, after whom this species was named. Mr Norton located flowering plants, which later included the type specimen, within a mile of the railway at Mt. Victoria - in the upper Blue Mountains, about 120 km west of Sydney. The type specimen is in the British Museum of Natural History, London. The name Adenochilus refers to the glands on the labellum.
Description
A. nortonii is a small plant up to 25 cm tall with a solitary glabrous ovate to cordate leaf, at or near the base of the stem which grows from a thin and fragile modified tuberoid. The white flowers are generally produced singularly, but twin flowers have been observed on robust specimens. The dorsal sepal is hooded and gives the flower a distinctive look. The labellum is marked with deep pink to red and has a band of yellow and white calli down the middle.
It has a short life above ground as the plants are dormant from late summer to early Spring (February to September).
Distribution
Adenochilus nortonii is endemic to New South Wales. It has a disjunct distribution which has been poorly understood by native plant and orchid enthusiasts. Little has been published on this mountainous species and herbarium collections are obviously incomplete.
The first plants were recorded from Mt. Victoria. Since that time it has been found in a number of locations in the upper Blue Mountains. Here it has been found at Adelina Falls, near Lawson at an altitude of 735 metres above sea level (its lowest recorded elevation in the Blue Mountains), Wentworth Falls, Leura, Katoomba, Narrow Neck, Medlow Bath, Blackheath to Mt. Victorla at 1040 metres altitude. These locations are on the southern side of the Great Western Highway facing a southerly aspect. Whilst there are parallel conditions on the southern side of the Bells Line of Road to the north, I know of no sightings. However, Wal Upton has informed me of a population at Clarence, 10km cast of Lithgow.
The next location north is the Barrington Tops population, 240km north of Sydney. Here it occurs at an altitude of 1585 metres above sea level, growing in sphagnum moss.
The northernmost population of A. nortonii occurs at Point Lookout, in the New England National Park, 75 km west of Coffs Harbour at an altitude of 1600 metres above sea level.
In the Illawarra Region/Kangaroo Valley, in the mountains west of Kiama this orchid has been found at Carrington Falls, initially by Brian Whitehead and Ron Tunstall over a decade ago. It would not surprise me if A. nortonii is later found at nearby Minnamurra Falls. The southern most plants were found by Graeme Bradburn in the same mountain chain at Fitzroy Falls, at an altitude of c. 600 metres. Throughout its southern range it has never been a common plant and only scattered specimens have been seen.
Habitat
I have noted two distinct habitats for A. nortonii. It is a species which always grows in shady situations and generally in high rainfall areas, as plants are never far from moisture.
Plants from the Upper Blue Mountains and the Illawarra region grow in wet and fairly heavily shaded situations, often at the base of dripping sandstone walls and caves, The soils are black and obviously heavily leeched due to the constant moisture. Companion plants include a number of fern species (such as Blechnum ambiguum), the native violet - Viola hederacea - and the insectivorous forked sundew, Drosera binata. Sometimes it grows in very close proximity to another restricted orchid - Rimacola elliptica, but in a totally different niche, the Rimacola growing in the sandstone rock crevices above the terrestrial Adenochilus.
The Barrington Tops population choose the lush Sphagnum moss pads as their home. They receive more light than their southern cousins as they grow under a loose canopy of Callistemon and Leptospermum shrubs which grow on the banks (and sometimes in) the small mountain streams. Here the Sphagnum is very thick and provides a perfect home for the Adenochilus. As this medium is kept evenly moist due to capillary action, whilst still allowing air to the specialised root-like tuberoids. In some areas there are pure colonies of the orchid, with numerous leaves of non-flowering plants resting on the surface of the moss. I am told the New England plants grow in a similar environment. The dormant plants would get quite cold in winter as the areas in which they grow experience frosty conditions with the odd snowfall thrown in for good measure.
Flowering period
In the upper Blue Mountains, A. nortonii flowers from November to early December, whilst the slightly more robust plants from Barrington Tops flower from December to early January It is interesting to note that the flowers follow the sun throughout the day, which also is an added bonus when photographing plants in situ!
Pollination
There has been nothing published to my knowledge on the pollination of A. nortonii. I have noticed small black flies in numbers hovering around flowers from the Wentworth Falls population. Of the l5 flowers studied, two later produced capsules. The flower stem had elongated on these fertilized plants, obviously to assist with seed dispersal. I did not witness any pollinations or observe pollen on the backs of the flies. At Barrington Tops I noted no visiting insects, even though there were scores of flowers. It is known that the flowers are not self-pollinating. Perhaps Adenochilus shares the same (or similar) pollinator as some of the small-flowered Caladenia species, such as the C. carnea complex.
Conservation Status
Whilst being rare and restricted in both distribution and habitat, most of the known populations of A. nortonii are secure in either National Parks or State Forest. It is difficult to spot out of flower and would generally only be under threat during the flowering period by indiscriminate collection of plants by enthusiasts. It is not known in cultivation, but may succeed in cool climates if grown in Sphagnum moss, kept moist, well shaded and without extremes of temperature. Growers who have previously tried to cultivate this plant note that they decline quickly after collection, rotting being the main problem. I know of no efforts to raise this species from seed. A. nortonii is listed among the rare or threatened Australian orchid species.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Location
Adenochilus gracilis													New Zealand

Detailed data: Aggregated observation dates from the GBIF.org network.
A colored month means an observation in habitat or collection date of a herbarium specimen with flower or inflorescence. The number refers to the year of last observation or collection.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Location

World Checklist for Adenochilus. With the permission of the Trustees of the Royal Botanic Gardens, Kew Published on the Internet
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