Citation: Gaertner, Fruct. 2:350 (1791).

Synonymy: M. tentaculata sensu J. Black, Fl.S. Aust. 459 (1948); M. tribuloides Desr. in Lam., Encycl. 3:635 (1792); M. truncatula Gaertner var. longispina Urban, Verh. bot. Ver. Prov. Brandenb. 15:67 (1873); M. tribuloides Lam. var. truncatula (Gaertner)Koch, Syn. Fl. Germ. Helv. edn 1, 1:162 (1836).

Common name: Barrel medic, snail (or caltrop) medic.

Description:
Sparsely villous annual; branches to 50 cm long; leaflets obovate, rarely obcordate, 7-20 x 6-15 mm, cuneate, denticulate near the apex, upper surface glabrous or sparsely hairy, underside more densely hairy; stipules ovate-lanceolate to narrowly lanceolate, incise-dentate to laciniate in the lower half; peduncle cuspidate, 1-5-flowered, shorter or longer than the corresponding petiole, covered with long simple hairs.

Flowers 5-8 mm long, on pedicels shorter than the calyx tube; bract lanceolate, acuminate, often auriculate basally, longer than the pedicel; calyx 2.5-4 mm, covered with simple hairs, 5 veins arising from the base and each extending into a slender acuminate tooth longer than the calyx tube; petals yellow; standard obovate; wings usually shorter than the keel.

Young pod enclosed within the calyx, more or less densely covered with simple hairs, occasionally with glandular hairs; mature pod cylindrical, hard-walled, nearly always sparsely villous, 4.5-8 mm diam., 6-12m high, light-yellow to dark-grey, spiny, rarely tubercled; coils 3-6, appressed, turning clockwise and anticlockwise; transverse veins scarcely anastomosing, joining a very thick lateral vein separated from the slender but distinct central vein by the groove which at maturity becomes filled with spongy cellular tissue; spines 7-11 on each side of the coil, 1-4 mm long, stocky, sometimes curved or with a thickened base, each arising partly from the lateral and central veins; seed 2.5-4.5 mm long, pale-yellow to brown, 1 or 2 in each coil.

Image source: fig. 350P in J.P. Jessop and H.R. Toelken Ed. 1986. Flora of South Australia (4th edn).

Distribution:  Widely established in S. Aust., and now extending into the pastoral areas, where it is being sown. S.Aust.: NU, FR, EA, EP, NL, MU, YP, SL, KI, SE.   W.Aust.; N.T.; ?Qld; N.S.W.; Vic.   A Mediterranean species. Conservation status: naturalised Flowering time: Sept. — Nov.

SA Distribution Map based on current data relating to specimens held in the State Herbarium of South Australia

Biology: No text

Taxonomic notes: Three varieties recognised by Heyn (p. 96) are treated by K. A. & I. Lesins (p. 168) as one variable species.

Author: Not yet available