Common name: Spiny Emex, Three-cornered Jacks, Doublegee
Rumex hypogaeus T.M.Schust. & Reveal APNI* Synonyms: Emex australis Steinh. APNI*
Description: Decumbent herb with stems to 80 cm long, and to 40 cm high, glabrous.
Leaves with lamina ovate, 3–9 cm long, 15–70 mm wide, apex obtuse to broad-acute, base truncate to cordate, margins ± finely crenate; petiole 2–10 cm long.
Male perianth segments 1.5–2 mm long, c. 0.5 mm wide. Female flowers with outer 3 perianth segments with 2(-4) pits above the cuneate base, with a very sharp, rigid, laterally spreading spine at apex; inner 3 segments erect, broad-triangular to broad-ovate, the midrib excurrent as a short, pungent mucro.
Fruiting perianth hardened, ± parallel-sided above cuneate base, 9–13 mm wide including terminal spines. Achene trigonous, brown.
Distribution and occurrence: Widespread weed in NSW; also naturalised in Qld, Vic, SA, NT, WA. Native of southern Africa. A weed of pasture and cultivation; the spiny fruit can cause lameness.
NSW subdivisions: *NC, *CC, *SC, *NT, *ST, *NWS, *CWS, *SWS, *NWP, *SWP, *NFWP, *SFWP
Other Australian states: *Vic. *W.A. *S.A.
A weed of pasture and cultivation; the spiny fruit can cause lameness. Much more common than E. spinosa, with which it hybridises when growing together. The first leaves on seedlings are obtuse (versus acute in E. spinosa) but later leaves are less different in shape. See also Weeds in Australia profile compiled by K.L. Wilson & P.G. Kodela (2007).
Text by K. L. Wilson (1990), edited Feb 2007; name updated by H. Sauquet (Oct 2020)
Taxon concept: Flora of NSW 1 (1990)
APNI* Provides a link to the Australian Plant Name Index (hosted by the Australian National Botanic Gardens) for comprehensive bibliographic data
***The AVH map option provides a detailed interactive Australia wide distribution map drawn from collections held by all major Australian herbaria participating in the Australian Virtual Herbarium project.
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