pronounced: lep-toh-SPER-mum pol-ee-gal-ee-FOH-lee-uh subspecies TROP-ik-um
pronounced: lep-toh-SPER-mumflav-ESS-kenz
Leptospermum derives from two Greek words, λεπτος (leptos), thin, fine or delicate, and σπερμα (sperma), a seed; polygalifolium (Latin folium, a leaf) – has leaves like the genus Polygala. Tropicum is from the Greek τροπικος (tropikos), the solstice, i.e. tropical. In the synonym, flavescens is Latin for 'becoming yellow'.
This Australian native is found from Cape York in North Queensland right down the east coast to the very south of NSW, extending inland for up to about 500 km. It is usually, but not always, found in sandy soils, or soils derived from sandstone, often in moist depressions or along watercourses. It also occurs on Lord Howe Island. The type species was collected at Port Jackson in 1796.
It is a medium-sized shrub with many twiggy angular branches having reddish brown bark. The leaves are linear-lanceolate, sub-mucronate, and 3-nerved, and are tipped with pink.
The solitary flowers, white tinged with yellow, grow out of the apex of the branch. The bracts are deciduous, and the petals roundish, pure white but turning yellowish when dry. There are about 20 stamens that incline inwards, and the anthers are orange-brown. The style is rather thick, and about the same length as the stamens.
There are several subspecies:
• ssp. polygalifolium is a smallish one from the central NSW coast;
• ssp. montanum , from the mountains of north-east NSW, is a rounded shrub with its new growth silky-haired and sometimes bronze-coloured;
• ssp. cismontanum usually has dull grey-green leaves, and comes from coastal swamps in south-east Queensland and north-east NSW; it can grow to 4 m in height;
• ssp. howense is from the cliffs and ledges and mountain-tops of Lord Howe Island, a rounded shrub about 2 m high, but occasionally reaching 6 m;
• ssp. tropicum, from wet coastal heaths, on dunes and in open woodland on sandy soils in central and north Queensland. The form known as ‘Cardwell’ (the plant pictured) comes from the area around the town of that name; and
• ssp. transmontanum grows in dry sandy alluvial soils and on rock areas by watercourses, west of the Great Dividing Range in central and southern Queensland and northern and central NSW.
There are quite a few uses for the plant in folk medicine, especially in Malaysia. A decoction of the leaves is used to treat constipation, stimulate the appetite, and relieve stomach discomfort. The leaves are also used to treat lethargy, hypertension, diabetes and kidney problems. A volatile oil is extracted from the leaves, and used as an inhalation to relieve bronchitis. This oil is also used as an embrocation to treat rheumatism.
Leptospermum polygalifolium is often used in hybridization, and many of the garden cultivars are descended from it in some way.