Wahlenbergia gracilis, commonly known as Australian bluebell[1] or sprawling bluebell is a perennial tufted herb from the family Campanulaceae.[2] The species is widespread throughout eastern Australia, with a range from Cape York to southern Tasmania.[3] The species is not considered at risk.
Wahlenbergia gracilis is a perennial, tufted herb ranging from 5 to 80cm in height[4] which is usually erect or sprawling, and is multi-branched from basal stems. Tghe stems branch from a thickened taproot. Leaves are alternate, or sometimes opposite near to the base of the stem.[5] Leaves are usually obovate to narrowly elliptic on lower stem, and lanceolate to linear on the upper stem, commonly small between 2-60mm long and 0.2-10 mm wide. Margins are flat or can be undulate, usually entire or sometimes with small, callus-teeth or occasionally serrate. Leaves are glabrous, with lower leaves sometimes sparsely hirsute. Conspicuous flowers are in thyrsoids which make up the upper half of the plant, pedicels are between 2-11cm long and glabrous or sometimes sparsely hirsute. Bracteoles are linear and glabrous. Hypanthium is obconic to obovoid in shape and glabrous. W. gracilis usually has 5 sepals, but sometimes 3 or 4, usually 1-3mm long and narrowly triangular. The corolla is deeply campanulate in shape, 1-4.5mm long, blue/mauve in colour but sometimes pink or white, usually 5 lobes, but sometimes 3 or 4, elliptic to ovate, and 1.5 - 6mm long. Ovary is usually 3-locular or sometimes 2-locular. Flowers have been observed to open and close in response to light availability.[6] Capsule is obconic to obovoid in shape, 2.5-7mm long, 1.5-3.5 mm wide, glabrous.
Wahlenbergia gracilis is sometimes difficult to distinguish from other Wahlenbergia species but is characterised by obconic to obovoid capsules, its perennial habit, and its deeply campanulate corolla.
Wahlenbergia gracilis is native to Australia, New Caledonia, New Guinea, New Zealand and Tonga.[7] The Wahlenbergia genus is widespread throughout Australia. Wahlenbergia gracilis occurs mainly throughout eastern mainland Australia, with occurrences extending from Cape York Peninsula to southern Tasmania, and extending as far west as the Adelaide region.
Tolerant of many vegetation types, found in wet and dry forests, shrublands, woodlands and grasslands from moist but well-drained soil to poor, stony soils, and is well-adapted to disturbed sites. In Tasmania, it is commonly found in grasslands and grassy woodlands.[8] Smith notes that a distinguishing feature of W. gracilis is that it is commonly found in mesic areas, meaning environments containing a moderate amount of water.
Wahlenbergia gracilis is an accepted species, first published in Monographie des Campanul?es 142 (1830).[9] There are seventeen synonyms of the species,[10] denoting some previous misidentification and difficulty in distinguishing Wahlenbergia species.
Wahlenbergia gracilis has a fibrous root system which can be important in stablizing soil and preventing erosion.[11] It also plays an important role for a number of native pollinators, including native bee species and a number of butterflies notably Vanessa kershawi (Australian painted lady), Zizina labradus (common grass-blue) and Ogyris olane (Eastern bronze-azure). It may provide habitat and resources for a range of native insect.