Survey of threatened plant species in South East Queensland biogeographical region queensland cra/rfa steering committee survey of threatened plant species in

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3.22 Medicosma elliptica T.G. Hartley

3.22.1 Summary

Medicosma elliptica has a very restricted distribution in the Dawes and Many Peaks Ranges approximately 25 km south-south-west of Miriam Vale (SF 391 Fty 1007 Granite Creek State Forest). The species has a total geographic range of approximately 20 km with an area of occupancy of less the 50 hectares. The total population has been estimated to be 100-250 individuals. It grows in mountainous terrain on relatively rocky, moderately to very steeply inclined hillslopes with varying aspects and at elevations between 200-580 m above sea level. The soils are well drained, shallow to deep, grey brown to reddish brown loams. The vegetation community is a complex notophyll vine forest. M. elliptica grows in the mid stratum of this community type. Current or perceived threats to the continued survival of M. elliptica in the wild are the encroachment of fire into its habitat and the spread of the weed Lantana camara (lantana).

3.22.2 Species description and identification

The genus Medicosma is placed in the family Rutaceae. Medicosma presently contains 22 species and occurs in Australia, New Guinea and New Caledonia. Six of the species are endemic to eastern Australia.

Medicosma elliptica T.G. Hartley was formally described in 1985 from material collected from the upper reaches of Granite Creek, approximately 90 km north west of Bundaberg (Hartley 1985). The botanical description of Medicosma elliptica is as follows:
Shrub or small tree to 7 m high. Branchlets glabrous; terminal buds corky. Leaves (sub)opposite, 5-13.5 cm long; petiole glabrous or nearly so, flat adaxially, neither swollen apically nor articulated with the blade, 4-10 mm long, 1-1.5 mm wide at the middle; blade subcoriaceous, glabrous, conspicuously oil-dotted ,elliptic or elliptic-obovate (or obovate), 4.5-12.5 cm long, 1.8-6 cm wide, about 2-3 times as long as wide, the base acute to attenuate, the main veins 11-13 on each side of the midrib, diverging at an angle of 50-60°, the apex (acute or) obtuse to rounded, usually retuse. Inflorescences axillary, one- or few-flowered, subsessile or with herbaceous axis to 2 mm long; pedicel(s) obsolete to 1 mm long. Flowers bisexual, 5.5-6 mm long, tetragonously ovoid in bud; sepals densely appressed-pubescent, imbricate for about 1/2 their length, broadly ovate or suborbicular, about 2 mm long; petals white, densely pubescent abaxially, narrowly elliptic, 4.5-5.5 mm long. Follicles glabrous or nearly so, approximately 7-10 mm long, wrinkled when dry, dehiscing along the adaxial, apical edges and partially down the abaxial side, mostly with solitary seed. Seeds subovoid, 5-6 mm long, with suborbicular, subfleshy piece of tissue attached near hilum. (Hartley 1985). For a more detailed description and illustration refer to Hartley (1985).
Medicosma elliptica is related to M. obovata and M. sessiliflora. It can be distinguished from M. obovata by its leaf shape and from M. sessiliflora by the angle of divergence of the lateral veins of its leaves. The three species are also geographically separated. Details of these differences are present in Table 3.22.1.
Table 3.22.1. Characters distinguishing Medicosma ELLIPTICa, Medicosma obovata and medicosma sessiliflora.

Characters	M. elliptica	M. obovata	M. sessiliflora
petiole	neither swollen apically nor articulated with the blade	often slightly swollen apically and sometimes obscurely articulated with the blade	swollen apically and often articulated with the blade
leaf shape	elliptic or elliptic-obovate, rarely obovate, 2-3 times as long as wide	obovate rarely elliptic, 1.5-2 times as long as wide	elliptic or elliptic-oblong to oblanceolate, 2-4 times as long as wide
leaf base	acute to attenuate	obtuse to attenuate	cuneate to rounded
No. of lateral veins on each side of midrib	11-13	8-10	(9)12-16
angle of lateral veins	50-60°	50-60°	70-80°

3.22.3 Current conservation status

Medicosma elliptica is presently listed on the schedule of the Queensland Nature Conservation Act 1992 as “vulnerable wildlife”. The species has been assigned a national conservation status of V (vulnerable) by ANZECC (1993). It is also listed on Schedule 1 Part 2 (vulnerable) of the Commonwealth Endangered Species Protection Act 1992.

3.22.4 Distribution and abundance

Details from Queensland Herbarium specimens of Medicosma elliptica are listed in Appendix 1.21. A total of 13 specimens of M. elliptica have been collected from an area within SF 391 (Fty 1007) (Granite Creek State Forest) approximately 25 km south-south-west of Miriam Vale. The species has a total geographic range of approximately 20 km with an area of occupancy of less the 50 hectares (W.J.F. McDonald pers. comm.). The total population has been estimated to be 100-250 individuals (W.J.F. McDonald pers. comm.).

3.22.5 Habitat

The sites are situated in mountainous terrain on relatively rocky, moderately to very steeply inclined hillslopes with varying aspects and at elevations between 200-580 m above sea level. The soils are well drained, shallow to deep, grey brown to reddish brown loams. The geology is predominantly basalt/ultrabasic rock. The area is mapped as Muncon Volcanics, a Triassic formation made up of intermediate and basic lavas (andesite and basalt), tuff, agglomerate, siltstone and lithic sandstone.

The vegetation community is a complex notophyll vine forest with Araucaria cunninghamii, Ficus macrophylla and Lophostemon confertus emergents. Common canopy species included: Argyrodendron trifoliolatum, Ficus platypoda, Planchonella queenslandica, Beilschmiedia obtusifolia, Cinnamomum oliveri, Premna lignum-vitae, Olea paniculata, Brachychiton discolor, Mischarytera lautereriana and Syzygium australe. Other low trees, shrubs, epiphytes and vines included : Wilkiea macrophylla, Randia chartacea, Cleistanthus cunninghamii, Austromyrtus bidwillii, Bosistoa pentacocca, Actephila lindleyi, Phyllanthus brassii, Melodinus australis, Elaeagnus latifolia, Ripogonum album, Melodorum leichhardtii, Clematis glycinoides, Platycerium bifurcatum, Dendrobium speciosum and Davallia pyxidata. The area has been modified by previous human disturbance, during the logging of Araucaria cunninghamii (hoop pine). The disturbance associated with harvesting of hoop pine from the complex notophyll vine forest has assisted in the establishment of lantana (Lantana camara) throughout the community.
M. elliptica grows in the mid stratum of this community type.

3.22.6 Life history and ecology

Very little is known about this species. The cultivation of other species of Medicosma has been by seed or cuttings. The seed is best sown fresh, although germination is generally erratic due to the presence of inhibitors (Elliot & Jones 1993). Cuttings of hardened new growth may be successful but often slow to strike. (Elliot & Jones 1993).

M. elliptica is a small tree with an unknown life span. The main method of reproduction is by sexually produced seeds. Very little is known about the floral ecology of M. elliptica. Herbarium records and field observations indicate that M. elliptica flowers from December to May. Fruits have been observed in December and June. The breeding system of M. elliptica is unknown.
The seed is not retained on the plant for a long time but is forcibly ejected from the fruit when mature. The dispersal distance achieved by this mechanism is unknown but would be expected to be only a relatively short distance. It is suggested that the subfleshy appendage attached to the seed may further aid in the dispersal of seed by the attraction of ants to collect the seed (Hartley 1985). Ant-dispersal is known to occur in other genera with similar seed characteristics in the family Rutaceae (Berg 1975).
It is suspected that all stages of the life cycle M. elliptica are susceptible to fire. It is not known whether M. elliptica is capable of suckering or resprouting from the base of the tree trunk.

3.22.7 Threats

In the past the area has been logged for Araucaria cunninghamii (hoop pine) and a portion of the habitat has been cleared for the establishment of hoop pine plantations. The present policy of the Department of Primary Industries, Forestry is not to harvest timber from rainforest communities.

The main potential threats to the continued existence of M. elliptica in the wild include the encroachment of fire into its habitat and the spread of the weed Lantana camara (lantana).

3.22.8 Management research and conservation measures

The principal habitat management issue for this species is the eradication of weeds, particularly lantana (L. camara) from the habitat. Control of such large infestations of a weed species can only be successfully and economically achieved by biological agents. Research into the biological control of L. camara is currently being undertaken by staff of the Department of Natural Resources.

A total fire exclusion policy should be practised. Liaison is required with Department of Primary Industries, Forestry and rural landholders adjoining the State Forest to alert the local community to the issue of fire management within the area.
A more accurate survey of the species’ distribution in the State Forest is required. There is no doubt that further surveys of appropriate habitats are required to substantiate whether there are additional populations in the vicinity.
There is little information available on the autecology and reproductive biology of Medicosma elliptica. Studies into regeneration techniques, the species’ response to disturbance and habitat requirements are needed.
The whole of the vine forest habitat should be considered for protection. The declaration of a State Forest Scientific Area under the Forestry Act 1959 should be considered.

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