Scientific Name:
Emex australis Steinh.
Vernacular Name(s):
Spiny emex; Three-cornered Jack

Annual herb. Stems prostrate to ascending, often reddish. Petiole = or > lamina except in uppermost lvs, to c. 10 mm long. Lamina 2.5–7 × 1.5–4.5 cm, ovate-oblong to almost oblong, entire; base truncate to subcordate; apex obtuse or subacute; ochreae initially c. 1 cm long. ♂ infl. to c. 3 cm long, much shorter towards branch ends; perianth 1.2–1.8 mm long, green. ♀ fls with perianth subtended by membranous bract; outer segments 2–4 mm long at flowering, with an outward-directed spine c. = segment; inner perianth segments exserted from outer but acuminate tip soft and much < spines. Fr. c. 1 cm long including spines, indurated and rigid; outer segments with 4 deep depressions; inner segments completely enclosing the nut; nut glossy, trigonous, c. 5 mm long.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]


Flowering: Jul.–Apr.

Biosecurity New Zealand 2012: Regional Pest Management Strategies Database.