Triumfetta semitriloba
(burweed)

Preferred Scientific Name

• Triumfetta semitriloba Jacq.

Preferred Common Name

• burweed

Other Scientific Names

• Heliocarpus hirtus (Vahl) R.O.Williams & Sandwith
• Triumfetta abutiloides A.St.-Hil
• Triumfetta hirta Vahl
• Triumfetta obscura A.St.-Hil.
• Triumfetta oxyphylla DC.
• Triumfetta rubricaulis Kunth
• Triumfetta tricuspis A.St.-Hil.

International Common Names

• English: black bush; sacramento bur; sacramento burbark; triumfetta
• Spanish: cadillo de perro; cadillo de perro; escobilla amarilla; escobilla amarilla; gúizapol de Borrego; guizazo de caballo (Cuba); huizapolillo; mozote colorado; mozote colorado; pegadillo
• French: cousin-petit; mahot-cousinrouge; petit mahot-cousin; tête à nègre

Local Common Names

• Brazil: carrapicho; carrapicho-de-calçada; carrapicho-miúdo; juta-nacional; juta-nacional
• China: fei dao ci shuo ma
• Cuba: guizazo de caballo
• Ecuador/Galapagos Islands: pegadillo
• Guam: dadangsi; masiksik lahe
• USA: black bush; Sacramento bur; Sacramento burbark; triumfetta

EPPO code

• TIUSE (Triumfetta semitriloba)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Malvales
•                         Family: Tiliaceae
•                             Genus: Triumfetta
•                                 Species: Triumfetta semitriloba

There appears to be some confusion regarding taxonomic placement of the genus Triumfetta. It is generally regarded as a member of the Malvaceae family, though placed by some in the Tiliaceae. Nonetheless, it is a clearly demarcated genus, containing several to many species, depending on the classification used. Triumfetta semitriloba has cleary defined taxonomic limits, but given its very broad native range, from Florida to Argentina and Chile, it is not surprising that several varieties are reported, including var. berlandieri, var. brasiliensis, var. martiana and var. surinamensis, and a form, f. althaeoides.

Adapted from: Long and Lakela (1976); Howard (1989); Liogier (1994); Flora of China (2015); PIER, (2015).

T. semitriloba is a commonly single-stemmed, perennial but short-lived shrub, generally 1 m tall or more, up to 3 m, or occasionally a herb or subshrub 0.5 m tall. Stems erect, with a woody main stem to 3 cm diameter, with smooth, grey bark. Branchlets pubescent and densely stellate especially when young, hairs simple and stellate, becoming glabrate with age. Leaves variable in shape, usually broadly ovate or rhombic-ovate to lanceolate especially in the upper parts of the plant, sometimes obscurely 3-lobed and 3-nerved from base, 3-8 cm long, 3-6 cm wide, stellate pubescent, more so on lower surface, margins irregularly serrate-dentate, apex acuminate, base very broadly cuneate to truncate, rarely subcordate, Petioles 0.5-(1.5-6)-9.5 cm long growing progressively shorter toward the plant apex. Flowers are 5 mm long, in leaf axils, with 5 yellow petals. Flower buds are cylindrical, ca. 4 mm, pubescent, pedicel 2-3 mm, sepals linear, 4-7 mm long, abaxially stellate pubescent, appendage subapical, ca. 0.5 mm, pubescent. Petals narrowly elliptic-obovate or oblanceolate, 3.5-6.5 mm long, about as long as the sepals, stamens 15-20, filaments glabrous. Ovary 3-loculed, spiny; style 3-5 mm; stigma ± 3-lobed. The fruits, with scattered reflexed hairs on the hooked spines, are round burs 6-8 mm in diameter, borne in groups of two or three. Each fruit has three compartments containing 1-3 brown seeds, 2 mm long and broadly oval. Capsule globose, body 3-5 mm in diameter, 3-loculed, indehiscent, glabrescent; spines 1.5-2 mm, retrorsely pilosulose at base, conical at base, tip hooked.

It is assumed that the introduction of T. semitriloba throughout the Pacific occurred in the early twentieth century, if not before. The first record of its presence in the Pacific islands was on Maui, Hawaii, in 1910 (Motooka et al., 2003), and it was also noted as a noxious weed in Hawaii by the middle of the 1900s (Hosaka and Thistle, 1954).

Soil drainage

• free
• impeded

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Special soil tolerances

• infertile
• shallow

T. semitriloba appears to require disturbance for successful establishment. Given an equal start, it competes well with other herbs, grasses and shrubs in full sun or partial shade (Motooka et al., 2003).

The fruit are burs with specially adapted hooks or barbs that cling to clothing and fur, and seeds are dispersed when the burs attach themselves to passing animals. The weed is also commonly known simply as ‘burweed’ which reflects this.

There is no information available on the reasons for international introduction, though having no real use, intentional introduction is considered unlikely. It is possible that T. semitriloba burs were introduced accidentally, hitchhiking on clothing and fur, either via people or livestock and their products.

T. semitriloba is an alternative host of the leafhopper Empoasca formosana, which is a vector of cadang-cadang disease on coconuts. However, the plant was found not to be a reservoir for the actual virus responsible for cadang-cadang (Bigornia, 1963).

T. semitriloba is generally found growing in small patches and as single, dispersed plants, but can be numerous in disturbed forest sites. In these situations, it can prevent the establishment of native species, such as in the Haleakala National Park in Hawaii (Motooka et al., 2003).

The hooked burs are a nuisance to people and especially to livestock and other animals, in both pastures and forests, where the plant is present (Motooka et al., 2003).

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerant of shade
• Has high reproductive potential
• Has high genetic variability

• Threat to/ loss of native species

• Competition - monopolizing resources
• Produces spines, thorns or burrs

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant
• Difficult to identify/detect in the field
• Difficult/costly to control

T. semitriloba has no real use or value. Foliage is reported to have no forage value, and the stem is too small to be a meaningful source of fuelwood (Haselwood and Motter, 1966). Fibres extracted from the bark of larger stems are reported to have been used by the inhabitants of Rapa Nui (Easter Island) to make fishing lines, and related species are reported to have medicinal value.