Calomnion complanatum - endangered species

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the moss Calomnion complanatum (Hook.f. & Wilson) Lindenb. as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of endangered species is provided for by Part 2 of the Act.


The Scientific Committee has found that:


1. Calomnion complanatum (Hook.f. & Wilson) Lindenb. (Family Calomniaceae) (Tree-fern Calomnion) is a small moss that grows almost exclusively on the trunks of tree ferns, most commonly Dicksonia antarctica although it has also been found on Cyathea spp. in other states. The most recent description of C. complanatum can be found in the Flora of Australia, Volume 51, Mosses 1 (Catcheside and Bell 2006) where it is described as: “Plants to 10 mm long. Leaves often caducous; lateral leaves elliptic to oblanceolate, often curling inwards dorsally when dry, 0.75–1.25 mm long; dorsal leaves broadly ovate to orbicular, c. half the length of the lateral leaves; in both types margin unistratose, plane, minutely and regularly crenulated; costa ending a little below the apex; laminal cells 7-10 μm diam. Perichaetial leaves crowded and overlapping, linear-spathulate, 2.5-3.0 mm long. Setae 2-3 mm long. Capsules ovate-cylindrical, exserted, c. 1 mm long. Spores c. 14 μm diam., brown”. Other descriptions can be found in Vitt (1995), Meagher (1999), Dalton (1998) and in Sainsbury (1955), (as Calomnion laetum). The family Calomniaceae contains one genus, Calomnion, with nine species. C. complanatum occurs only in south-eastern Australia and New Zealand.

2. The life cycle of Calomnion (typical of all mosses) is characterised by an alternation of two generations: a haploid gametophyte that produces gametes and a diploid sporophyte that produces haploid spores. Sporophytes of C. complanatum have been recorded in Australia only once (Catcheside and Bell 2006), and thus reproduction is most likely by vegetative means. Most mosses have the ability to reproduce from just a few cells of stem or leaf from which the protonema is initiated, and it seems likely, in the absence of sporophytes, that C. complanatum reproduces in this way. Dalton (1995) comments that the leaves of C. complanatum are highly deciduous and may act as vegetative propagules.

3. Calomnion complanatum grows only on the trunks of tree ferns in moist gullies of mountainous areas with relatively high rainfall. The species has been recorded from only three locations in NSW: Cambewarra Mountain (in 1903), Rocky Creek Canyon on the Newnes Plateau (in 1990), and two sites at Mount Wilson, Zircon Creek (in 2001) and Waterfall Reserve (in both 2001 and 2007). At each site only a few individual plants have been recorded. At the Waterfall Creek site the species was observed in 2007 on only one tree fern trunk (A. Downing pers. comm. June 2008). The area of this reserve is less than 1 km2. At Zircon Creek it has been located on fewer than 10 trunks, in an area <0.5 km2. While it is possible that other populations of C. complanatum may be located in the future, field surveys by Australian and international bryologists during the International Botanical Conference in 1981, and the Australasian Bryological Workshop in 2001, did not locate C. complanatum anywhere in NSW other than the two Mt Wilson sites. In October 2006, a search for C. complanatum on tree ferns on Cambewarra Mountain and Barrengarry Mountain was unsuccessful (A. Downing pers. comm. June 2008). However, at the time of survey the forest was extremely dry, and rainfall for that year was approximately half the average. It is possible that further survey during a wetter period may relocate the species at these sites.

4. At both Mount Wilson and Cambewarra Mountain, the closed forests are associated with basalt soils, overlying shales and/or sandstone. The closed forest on Cambewarra Mountain is quite diverse, with many genera and many species of rainforest trees, vines and ferns. The closed forest at Mount Wilson is dominated by Coachwood (Ceratopetalum apetalum) and Sassafras (Doryphora sassafras). Rocky Creek Canyon is cut into sandstone with underlying shales on the Newnes Plateau.

5. Individuals of C. complanatum are small, easily overlooked, and not dissimilar to a number of other species that grow on tree fern trunks, including Rhizogonium distichum and R. novaehollandiae, Hymenodon pilifer and young stems of Lopidium concinnum. C. complanatum can be distinguished from Rhizogonium because the leaves of the latter are in two lateral rows with the stem clearly visible between them whereas in C. complanatum a third row of leaves masks the stem. C. complanatum can be distinguished from H. pilifer because the leaves of the latter species are very pale and usually arranged all around the stem (Beever et al. 1992).

6. Elsewhere in Australia, C. complanatum is known from Victoria and Tasmania. Catcheside and Bell in the Flora of Australia (2006) comment: “Very rare on the trunks of tree ferns in humid gullies in N.S.W., Vic and Tas”. In Victoria, C. complanatum has been recorded in wet forest on Wilson’s Promontory (Meagher 1999) and near the West Tyers River in Gippsland. In Tasmania, C. complanatum is found on damp sandstone (A. Downing pers.comm. June 2008) and has been recorded from two locations: Stanley in NW Tasmania in 1980 (Stone 1990) and Strahan in SW Tasmania in 1995 (Dalton 1998). C. complantum was listed as a species in need of protection by Scott et al. (1997) in a report to Environment Australia on the conservation status of Australian bryophytes and in Victoria it is listed as threatened under the Flora and Fauna Guarantee Act 1988. In New Zealand, C. complanatum is not uncommon on the trunks of tree ferns including Dicksonia squarrosa and Cyathea spp., as well as the fern Blechnum fraseri and the palm Rhopalostylis sapida (Beever et al. 1992; Sainsbury 1955).

7. Calomnion complanatum is threatened in NSW by environmental stochasticity due to its highly restricted geographic distribution, the small number of locations, and low population size. Reduction in rainfall and increases in fire frequency as a result of climate change may also threaten the species habitat (Hennessy et al. 2004; 2005). The Mt Wilson sites are potentially threatened by exotic weed invasion and human disturbance as they are close to popular picnicking and bushwalking sites. If the species still exists in the Cambewarra area it may be affected by lantana. ‘Anthropogenic climate change’, ‘Invasion of exotic vines and scramblers’, ‘High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition’ and ‘Invasion, establishment and spread of Lantana (Lantana camara L. sens. lat)’ are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995.

8. Calomnion complanatum (Hook.f. & Wilson) Lindenb. is not eligible to be listed as a critically endangered species.

9. Calomnion complanatum (Hook.f. & Wilson) Lindenb. is eligible to be listed as an Endangered Species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

Clause 15

The geographic distribution of the species is estimated or inferred to be:

(b) highly restricted,


(e) the following two conditions apply:

(i) the population or habitat is observed or inferred to be severely fragmented;

(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations,

Clause 16

The estimated total number of mature individuals of the species is:

(b) low,


(e) the following two conditions apply:

(i) the population or habitat is observed or inferred to be severely fragmented;

(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations

Clause 17

The total number of mature individuals of the species is observed, estimated or inferred to be:

(b) very low


Professor Lesley Hughes


Scientific Committee

Proposed Gazettal date: 19/12/08

Exhibition period: 19/12/08 - 27/02/09


Beever J, Allison KW, Child J (1992) ‘The Mosses of New Zealand’, Second Edition. (University of Otago Press: Dunedin, New Zealand)

Catcheside DG, Bell DH (2006) Calomniaceae.. In ‘Flora of Australia Volume 51, Mosses 1’. (Ed. P. M. McCarthy) pp. 316, 367 – 368, 405. ABRS, Canberra and CSIRO Publishing, Melbourne.


Dalton PJ (1998) New locality records for some rare mosses in Tasmania. Papers and Proceedings of the Royal Society of Tasmania 132, 41-45.

Hennessy K, Page C, McInnes K, Jones R, Bathols J, Collins D, Jones R (2004) ‘Climate change in New South Wales. Part 1: Past climate variability and projected changes in average climate’. CSIRO Marine and Atmospheric Research, Aspendale, Victoria.

Hennessy K, Lucas C, Nicholls N, Bathols J, Suppiah R, Ricketts J (2005) ‘Climate change impacts on fire-weather in south-east Australia’. CSIRO Marine and Atmopheric Research, Aspendale, Victoria.

Meagher D (1999) Calomnion complanatum: an endangered moss found in Victoria. The Victorian Naturalist 116, 68-69.

Sainsbury GOK (1955) ‘A Handbook of the Mosses of New Zealand. Bulletin No. 5’. (Royal Society of New Zealand: Wellington)

Scott GAM, Entwisle TJ, May TW, Stevens GN (1997) ‘A conservation overview of Australian Non-marine Lichens, Bryophytes, Algae and Fungi’. Environment Australia, Canberra, A.C.T.

Stone IG (1990) Nomenclatural changes and new moss record in Australia: including a description of the protonema of Calomnion. Journal of Bryology 16, 261-273.

Vitt DH (1995) The genus Calomnion (Bryopsida): taxonomy, phylogeny, and biogeography. The Bryologist 98, 338-358.

Page last updated: 28 February 2011