Yellow Lantern Banksia

Appearance

"Banksia lemanniana" grows as an open shrub or, less commonly, a small tree to 5 m in height, with a spreading habit. The trunk has thin grey bark and can reach a diameter of 15 cm. Lower-growing plants that reach 1.6 m have been reported from coastal areas of Fitzgerald River National Park. The new growth is finely hairy and predominantly seen in summer, before losing its hair and becoming glabrous over two years. The stiff leaves are narrowly wedge-shaped or more oval and measure 3–9 cm in length by 1.2–3 cm wide. The leaf margins are serrated, with many teeth measuring 0.1 to 0.3 cm each.

Flowering typically occurs between October and January. Unlike those of most other banksias, the cylindrical inflorescences hang down from branchlets and measure 5–11 cm in length and 8–10 cm in diameter. They are green-yellow in colour and smell of honey, dripping large amounts of nectar. The buds are a rich chocolate brown in colour until the yellow flowers push through. The inflorescences turn grey as they age, and the old flowers remain as up to 20 large woody follicles develop. Oval in shape, wrinkled in texture and covered with fine hair, they can reach 4.5 cm long, 3 cm high, and 3 cm wide.

The obovate seed is 4–4.7 cm long and fairly flattened, and is composed of the wedge-shaped seed body proper, measuring 1.2–1.5 cm long and 1–1.3 cm wide, and a papery wing. One side, termed the outer surface, is dark brown and wrinkled, while the other is black and smooth. Both surfaces sparkle slightly. The seeds are separated by a sturdy dark brown seed separator that is roughly the same shape as the seeds with a depression where the seed body sits adjacent to it in the follicle. Seedlings have cuneate cotyledons which measure 1.2–1.5 cm long and 1.5–1.8 cm wide. These are dull green, sometimes with a reddish tinge, and the margin of the wedge may be crenulated. The hypocotyl is red and measures 1–2 cm high and 0.25–0.3 cm wide.

Distribution

"Banksia lemanniana" is found near the southern coast of Western Australia, most of its population protected within Fitzgerald River National Park. Outside the park, it reaches the Ravensthorpe Range to the northeast and the rabbit-proof fence to the east, as well as isolated populations westwards as far as Pallinup estuary. The annual rainfall is 500–600 mm. It is found on the tops and slopes of hills as well as flatter areas on rocky or lateritic soil, as well as sand, in mallee scrubland or heath. "Banksia lemanniana" is relatively secure as much of its range lies within a National Park, and it is not a species collected for the cut flower industry. It is hence classified as Not Threatened under the Wildlife Conservation Act of Western Australia.

Habitat

"Banksia lemanniana" is killed by bushfire and regenerates from seed. It is unclear how quickly seedlings take to reach flowering in the wild, but cultivated records suggest around five or six years. If fire occurs too frequently, plants are burned before reaching maturity or before they have produced sufficient seed to ensure regeneration of the population. This may cause a population decline or even local extinction. Too long a time between fires also causes population decline, as more plants die of natural attrition without releasing their seed, resulting in seed wastage.

"Banksia lemanniana" has been shown to have a low to moderate susceptibility to dieback from the soil-borne water mould "Phytophthora cinnamomi", unlike many Western Australian banksias. A study on cultivated plants in South Australia inoculated with "P. cinnamomi" and "P. citricola" found "B. lemanniana" to have an overall low susceptibility overall to both organisms, although 2-to-3-week-old seedlings appeared more vulnerable than 10-month-old ones.