# Bulbinella rossii

Bulbinella rossii, commonly known as the Ross lily, is a species of flowering plant in the family Asphodelaceae. It is an endemic megaherb of New Zealand's subantarctic Auckland Islands and Campbell Island. It was first described in 1845 by Joseph Dalton Hooker, from material collected on Campbell Island, as Chrysobactron rossii.
B. rossii reaches a height of up to 1 metre (3 feet 3 inches). It has dark green leaves and golden-yellow flowers. Its roots are often eaten by introduced pigs, but the species is avoided by cattle, goats and sheep. B. rossii was evaluated in the 2024 assessment by the New Zealand Threat Classification System as "At Risk — Naturally Uncommon".

## Description

Bulbinella rossii is a large, dioecious lily in the family Asphodelaceae and the subfamily Asphodeloideae, it reaches a height of up to 1 metre (3 feet 3 inches) in height and with a basal diameter of 40 mm. The dark green, fleshy, strap-like leaves and are 0.6–1 m long and 15–60 mm wide. The inflorescence is a cylindrical raceme up to 600 mm long. The golden yellow flowers it produces are densely crowded, 10–14 mm in diameter. The ovoid seed capsules it produces are 10 mm long, containing narrowly winged, dark brown seeds. B. rossii flowers from October to January and fruits from December to March.
Its leaves are 60 × 80 mm long and its raceme is 20 × 6 cm long with crowded flowers; the ovary is left undeveloped in male specimens; in female specimens, its tepals spread approximately 11–12 mm in diameter more erect and remaining, becoming more firm in texture as its fruit ripens; in female specimens; the capsules are broadly ovoid and the seeds are 6 mm long.

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## Taxonomy
### Classification

The Bulbinella genus was first established in 1843 by Carl Sigismund Kunth. Initially, six species from the Cape of Good Hope, in South Africa, were placed in the genus Bulbinella; three of them transferred from other genera and three of the species were described as new. In 1845, Joseph Dalton Hooker based his new genus Chrysobactron on B. rossii specimens collected from Campbell Island. The species was first published in the Flora Antarctica by him. In it, he noted that Chrysobactron was "very nearly allied" and had a similar appearance to the South African Bulbinella genus but decided not to move his new genus into it.
In 1906, botanist Thomas Cheeseman had more than once expressed doubts about the generic status of the New Zealand species and placed them in Bulbinella rather than in Chrysobactron. In 1952, Lucy Cranwell studied the pollination of various New Zealand species, she mentioned in her study the points of similarity between the grains of South African Bulbinella species and New Zealand Chrysobactron (now known as Bulbinella) species, but no other differences were mentioned by her.
There are twenty-three species in the genus Bulbinella; seventeen of which are located in South Africa, and six in New Zealand. A 2017 thesis by Collen Musara examined the genus Bulbinella and hypothesised that B. rossii is the closest resemblance to the South African species because of B. rossii's fibrous leaf bases that other New Zealand Bulbinella species do not possess.

### Etymology

The etymology of the genus, Bulbinella, translates to English as 'little bulb'. The specific epithet rossii is named after James Ross, the leader of Hooker's expedition. Hooker decided to name the specific epithet in honour of Ross because he brought many new species to him during their short stay on Campbell Island. The species is commonly known as the 'Ross lily'.

## Distribution

Bulbinella species are predominantly endemic to Africa, but six species are endemic to New Zealand, most of which are found primarily in the South Island. B. rossii is endemic to New Zealand's subantarctic Auckland and Campbell Islands. There, it is common and widespread from sea level to the highest parts of the island's mountains. Because it thrives where the ground has been disturbed, and because it is not particularly of interest to browsing animals, it is common near former human habitation sites and may form dense colonies in open herbfields and tussock grasslands. In 1970, botanist R. H. Taylor studied the vegetation and wildlife of Enderby Island. In his study, he noted that B. rossii appeared to be more common on the north and west sides of the island and the south-east sides of the island appeared to be dominated by southern rātā (Metrosideros umbellata) forests.

### Habitat

All New Zealand Bulbinella species are allopatric and prefer colder habitats with high water content. On the main Auckland Island, B. rossii occurs from sea level to high-altitude areas; but it is uncommon at lower-altitudes and is more common at higher-altitude areas where the ground is unfavourable for B. rossii to be rooted by introduced animals. On Campbell Island, B. rossii only becomes predominant above 250–300 m (820–980 ft) sea level.

## Ecology

   There is a weed which they call 'Bulbinella Rosi' [sic] growing on the island, which is spreading very rapidly, and appears to be going to over-run the country. The paddocks are simply a mass of it and where it is growing very thick, no other vegetation will thrive.
The roots of B. rossii are often eaten by pigs, but the species is avoided by cattle and goats. B. rossii's bitter taste also makes it unattractive to sheep. On Campbell Island in 1910, M. McKay, a stock inspector who was on the island to inform New Zealand's Ministry of Agriculture concerning the cases of sheep scab on the island, mentioned B. rossii was so common on the island it resembled an invasive species.
A 2013 research article by the New Zealand Journal of Botany on the floral biology and flower visitors on Campbell Island. In it, the researchers observed many of Campbell Island wētā (Notoplectron campbellensis) individuals feeding on the pollen and nectar of B. rossii, with as far as eight individuals on an inflorescence. B. rossii was the most frequently visited species from their study, other species from this study included: Melangyna novaezelandiae and Scoparia parmifera. B. rossii individuals are also known to be visited by hoverflies and small flies.
A 2019 study conducted by Polar Research examining the moths on New Zealand's subantarctic islands, noted that Graphania erebia, an endemic moth, was observed to visit B. rossii inflorescences and may be an important pollinator for the species. G. erebia moths either actively seek out B. rossii or are capable of travelling long distances at night and have more active foraging.

## Conservation

B. rossii was evalueted in the most recent 2024 assessment by the New Zealand Threatened Classification System as "At Risk — Naturally Uncommon" because its distribution is confined to the Auckland and Campbell Islands group, though its assessment is not the result of human disturbance.