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Electronic Flora of South Australia
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Electronic Flora of South Australia species Fact Sheet

Family: Labiatae
Plectranthus intraterraneus

Citation: S.T. Blake, Contr. Qld Herb. 9:33 (1971).

Synonymy: P. parviflorus sensu J. Black, Fl. S. Aust. edn 2, 4:734 (1957).

Common name: Cock spur flower.

Perennial shrubs to 1 m high, usually much-branched, with branches quadrangular becoming soft-wooded at the base, more or less densely covered with simple hairs and gland-tipped hairs or with sessile glands; leaves with the petiole 0.3-0.8 cm long; blade ovate to triangular, 1.5-4.5 x 1-4 cm, crenate to crenately lobed, double-crenate, cuneate to truncate at the base, with simple glandular hairs above, more densely hairy and with larger glands below.

Inflorescence a thyrse with a peduncle 4-8 cm long, with sessile cymose part-inflorescences each with 3-5 rarely 7 pedicellate flowers, with internodes elongated and longer than the part-inflorescences, with scale-like bracts; sepals fused to about half their length, 9-veined, 2-5.5 mm long, elongating after flowering, with pointed lobes at least when fruiting, zygomorphic, with a broad dorsal one, 2 medium lateral ones and 2 narrow anterior ones slightly curved upwards, with simple hairs and few large sessile glands oustide; corolla usually pale-violet, 2-lipped, with a lower lip longer than the tube, 9-12 mm long, with hairs and sessile glands on the outside of both lips, with posterior lip short and broad, with 2 short lateral lobes and broad 2-lobed dorsal lobe, with anterior lip narrowly elliptic-spathulate, slightly undulate; stamens inserted in the throat of the corolla tube, with slender filaments considerably broadened at the base, glabrous; anther 2-celled, more or less enclosed in the anterior lip; ovary on a thick disc, deeply 4-lobed, with a style inserted near the base and curved along the anterior lip of the corolla, with a 2-fid stigma.

Mericarps broadly oblong to almost orbicular in the surface view, c. 1 mm long centripetally compressed, with a concave outer surface and slightly convex inner surface, with a short transversely oblong attachment scar at the base, finely granulate to almost smooth.

image of FSA3_Plectranthus_int.jpg Flowering branch and calyx.
Image source: fig. 555C in Jessop J.P. & Toelken H.R. (Ed.) 1986. Flora of South Australia (4th edn).

Distribution:  usually in rocky terrain.

S.Aust.: NW, FR, EA, EP.   W.Aust.; N.T.

Conservation status: native

Flowering time: July — Nov.

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

Biology: Plants from the Flinders Ranges have usually few or none of the large glands on vegetative branches but they increase below the inflorescence while the reverse is found on a plant from the NW region of S.Aust.

Author: Not yet available

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