A plant was grown under this name at Monserrate in 1861. It was sent there by Sir William J. Hooker at Kew who in one of his many writings on Australian Plants : Hooker's journal of botany and Kew garden miscellany, Volume 8, p. 67, equates this species with Camphyromyrtus pluriflor F. Muell.; "leaves spreading, lanceolate-linear or oblong-lanceolate, acutish, awnless, with flat, perfectly entire margin; peduncles generally three-flowered. HABITAT On the banks of the Tambo, on the Snowy River, and on several of its tributaries."
So the plant was collected in south-eastern Australia. This is significant in determining the true identity of the plant once grown in Monserrate. Modern nomenclature for Harmogia virgata is generally given as Baeckea virgata which under revision in the 1990's by Tony Bean of the Queensland Herbarium was changed to Babingtonia virgata. This species according to this author is however restricted to New Caledonia. Australian plants previously known as Baeckea virgata were assigned to one of 8 species:
The Monserrate Harmogia virgata belongs therefore to one of the above!
See the ANPSA Blog Gumnuts for more detail and source.
So which of the Babingtonias comes from the banks of the Tambo?
Going back to Mueller:
George Bentham, Ferdinand von Mueller Flora australiensis: Myrtaceæ to Composita p.81
Baeckea - SECTION IV HARMOGIA
22. B. virgata, Andr. Bot. Rep. t. 598. Usually tall erect and loosely branched, attaining 10 to 12 ft., rarely low and diffuse. Leaves from linear-lanceolate to narrow-oblong, flat and often 1- or 3-nerved, usually acute and half to 1 in. long, but in some specimens all under half in. long, and occasionally some or nearly all obtuse both in the short- and long-leaved forms. Flowers small in the upper axils, usually several together in a loose umbel, on a common peduncle of 2 to 4 lines, the pedicels varying from 1 to 3 lines. Calyx-tube turbinate, at length hemispherical, about 1and a half lines diameter; lobes short and broad, the midrib more or less produced into a conical point or protuberance. Petals about 1 and a half lines diameter. Stamens 5 to 15, none opposite the centre of the petals ; filaments filiform ; anthers didymous, the cells globular, furrowed, opening in short slits; connective thickened into a gland almost as long as the cells. Ovary 3-celled, with 15 to 20 ovules in each cell round a peltate placenta. Capsule nearly flat-topped. Seeds usually angular. Embryo with the slender inflected end very short, with 2 small ovate cotyledons.—DC. Prod. iii. 229 ; Bot. Mag. t. 2127 ; Lodd. Bot. Cab. t. 341; Colla, Hort. Ripul. t. 6; F. Muell. Fragm. iv. 69 ; Leptospermum virgatum, Forst. Char. Gen. 48; Melaleuca virgata. Linn. fil. Suppl. 343; Harmogia virgata, Schau. in Linnaea, xvii. 238; Camphoromyrlus pluriflora, F. Muell. in Trans. Vict. Inst. i. 123 ; Harmogia umbellata, F. Muell. Fragrm. ii. 31 ; Baeckea umbellata, F. Muell. Fragm. iv. 69; Babingtonia virgata, F. Muell. Fragm. iv. 74.
N. Australia. Sandstone precipices, Victoria river, rare, F. Mueller.
Queensland. Bidwill; Upper Brisbane river, F. Mueller ; Moreton Bay, C. Stuart; Pine river, Fitzalan ; Rockhampton, Dallachy.
N. S. Wales. Grose and Hawkesbury rivers, R. Brown ; Blue Mountains, A. Cunningham ; northward to Macleay river, Beckler.
Victoria. On the Snowy and Tambo rivers, F. Mueller.
This species is also in New Caledonia ...."
Bean lists only one species as located at Tambo, Victoria, perhaps this Baeckea utilis is the Monserrate plant?
A revision of Baeckea (Myrtaceae) in eastern
Australia, Malesia and south-east Asia
Telopea 7(3): 1997
10. Baeckea utilis F.Muell. ex Miq., Ned. Kruidk. Arch. 4: 150 (1856).
Victoria: Midlands: Worragee, 12 km NNE of Beechworth, Johnson 7, 16 Aug 1989 (MEL). Eastern
Highlands: 0.4 km east of Back Creek junction, Forbes SJF239, 7 Jan 1980 (MEL, NSW); c. 9 km E of
Mt Little Tambo, c. 0.5 km NE from junction of Currawong road and McDougall Spur track, Davies
595 et al., 10 Nov 1988 (CANB, MEL, NSW). Snowfields: Bogong Range, Brooker 5534, Feb 1977
(CANB); W side of Bogong High Plains road, 25.6 km ESE of Falls Creek, Jobson 4119, Feb 1996
(BRI, CANB, MEL); near Native Cat track, c. 40 km E of Benambra, Bean 9441 & Jobson, Dec 1995
(BRI, MEL); Buffalo Plateau, Collier 2425, 21 Apr 1987 (HO). East Gippsland: Bendock area,
Delegate River, Gunmark road, Paris s.n., 1 Jan 1982 (MEL, NSW); Maramingo Creek swamp, 7 km
E of Genoa, Bean 9419 & Jobson, Dec 1995 (BRI, CANB, MEL, NSW).