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Electronic Flora of South Australia species Fact Sheet

Family: Labiatae
Prostanthera spinosa

Citation: F. Muell., Trans. Phil. Soc. Vic. 1:48 (1855).

Synonymy: Not Applicable

Common name: Spiny mintbush.

Description:
Small erect shrubs, sometimes scrambling and so semiprostrate, to 0.5 rarely to 2 m high; branches sparsely to densely hairy with curled to straight hairs 0.2-1 mm long, or glabrous except for a few hairs at the nodes, sparsely glandular; spines 6-14 mm long; leaves densely hairy or with scattered hairs, particularly on the petiole, lamina margin and midrib of abaxial surface; petiole 0.4-1 mm long; lamina narrowly ovate to broadly elliptic, 1.5-6 mm long, 1-4 mm wide; base acute to subobtuse; margin slightly recurved; apex obtuse; venation indistinct, midrib raised on abaxial surface.

Pedicel 1.5-8 rarely to 15 mm long, glabrous, sometimes with a few scattered minute hairs, or densely hairy, sparsely glandular or glands absent; bracteoles usually inserted at least half way up the pedicel, narrowly ovate to narrowly obovate, 0.9-2.5 mm long, 0.2-0.3 mm wide, glabrous or with an occasional hair on the margin and the abaxial surface, or densely hairy on the abaxial surface; calyx green with a maroon-brown tinge basally, upper lobe maroon-brown or green; outer surface densely hairy or with scattered hairs, moderately glandular; inner surface glabrous or with an occasional hair, or minutely hairy distally, scattered stalked hair-like glands sometimes present; tube 2-3 mm long; lower lobe very broadly ovate to subcircular, 1.5-2.4 mm long, 2-3.5 mm wide; upper adaxial lobe depressed to very broadly angular-ovate, 1.5-3 mm long, 2-4 rarely to 5 mm wide; corolla 8-14 mm long, pale-mauve, very pale-lilac to almost white, base of the tube and the lower surface of the tube more or less white, inner surface of the tube usually with orange to orange-brown lines or dots medially on the lower surface of the throat; outer surface glabrous basally, with a few scattered hairs distally or moderately hairy distally, or glabrous throughout; inner surface glabrous basally, moderately to densely hairy in the mouth and basal part of the lobes; tube 4-10 mm long; lower median lobe subspathulate to very broadly angular-obovate, 1.5-7 but usually 3-5 mm long, 2.6-8.5 mm wide; lateral lobes subcircular to obovate, 2.2-5.6 mm long, c. 2-4 rarely 5 mm wide; upper median lobe-pair depressed-ovate, 1.2-4.2 mm long, 4.8-8 mm wide; stamens inserted 3-4 mm above the base of the corolla; filaments 1.7-4 mm long, glabrous; anthers 0.8-1.6 mm long, usually crested dorsally, sometimes smooth, connective extended to form a basal appendage 0.7-2.1 mm long, distal end of appendage with 6-c. 12 rarely only 3 narrowly triangular trichomes; pistil 6-8 mm long; ovary 0.5-1.6 mm long; style c. 5-6.5 mm long; stigma lobes 0.2-0.4 mm long.

Fruiting calyx not enlarged; mericarps 2-2.5 mm long.

image of FSA3_Prostanthera_spi.jpg
Image source: fig. 556F in Jessop J.P. & Toelken H.R. (Ed.) 1986. Flora of South Australia (4th edn).
image of FSA3_Prostanthera_spi.jpg
Image source: fig. 556F in Jessop J.P. & Toelken H.R. (Ed.) 1986. Flora of South Australia (4th edn).

Published illustration: Althofer (1978) Cradle of incense, p. 148.

Distribution:  Commonly occurring in rocky areas and watercourses in association with mallee, Eucalyptus camaldulensis, E. baxteri, E. leucoxylon, Allocasuarina verticillata and Callitris rhomboidea communities, usually in sandy to sandy-loam soils overlying sandstone or limestone.

S.Aust.: FR, EP, KI.   N.S.W.; Vic.

Conservation status: native

Flowering time: Oct. — Jan.


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

Biology: No text

Author: Not yet available


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