Spermacoce brachystema

stiff-leafed spermacoce


Spermacoce brachystema

R.Br. ex Benth. 1867

pronounced: sperm-uh-KOH-key brack-ee-STEE-muh

(Rubiaceae — the gardenia family)


common name: stiff-leafed spermacoce

native 4Spermacoce is derived from the Greek σπερμα (sperma), a seed, and ακωκη (akoké), a point – the fruit has two points; brachystema is from βραχυς (brachus), short and στημων (stémon), a thread (stamen).

This plant occurs across most of northern Australia, and down the east coast as far as the Kempsey district in NSW. It has been found at an altitudinal range from near sea level to about 800 m. It is primarily a woodland species, but can also be found in eucalypt forest and wooded grassland. It is relatively uncommon (at least on Magnetic Island), but here it can be found along pathways or roadsides or in open ground. The plants photographed were by the side of the Cockle Bay road.

Spermacoce brachystema is an erect or spreading annual herb that normally grows to about 25 cm high, but can be found as tall as 60 cm. The stems are 4-angled, scabrous to hirsute, or sometimes glabrous.

The leaves are opposite, linear-lanceolate, 2 – 4.5 cm long, 2 – 7 mm wide, the apex acute to apiculate, the margins recurved to revolute; the lamina is scabrous to hirsute, more-or-less sessile. The calyx lobes are subulate, about 2 mm long.

There is a cluster of small flowers present at nearly all the nodes. The calyx lobes are green to brown with broad white margins, up to 2 mm long. The corolla is shorter than the calyx, papillose, with long erect hairs at the mouth of the corolla tube. The corolla is blue or whitish, about 2 mm long, pubescent inside on the throat, glabrous to papillose outside. The stamens are inserted towards the base of the tube.

The fruit is a capsule about 3 cm long, including the erect calyx lobes that persist at the apex. The tiny seeds measure about 2 by 1 mm, and have a reddish brown testa, reticulate-areolate; the embryo is white, the endosperm oily.


Photographed by Cockle Bay road, 2013, Nelly Bay 2015
Page last updated 6th April 2019