Australian Tropical Rainforest Orchids

Apostasia stylidioides

Yellow Grass Orchid

Apostasia stylidioides (F.Muell.) Rchb.f., Flora 55: 278 (1872).

Niemeyera stylidioides F.Muell., Fragm. 6: 96 (1867); Type: In rivulos silvarum circum sinum Rockingham’s Bay, 1867, J. Dallachy s.n. (lecto MEL; isolecto K, W).


Occurs in north-eastern Queensland from Bamaga to Ingham.

Altitude: 0-400 m.


Terrestrial evergreen herb forming grass-like clumps. Roots wiry, much branched, with variously sized fleshy tubercules. Stems single or multiple, erect, 10-25 cm long, tough, fibrous, wiry. Leaves scattered along stem, erect to pendulous, whorled, sessile, bases sheathing stem, lamina subulate, 10-20 cm x 0.7-1 cm wide, dark green, thin-textured, leathery, apex filiform. Inflorescence axillary, racemose or sparsely paniculate, arching to pendulous, 50-100 mm long, wiry; ovaries erect, slender. Flowers 5-40, non-resupinate, erect, star-shaped, 8-10 mm wide, yellow. Perianth segments and labellum similar in size and form; narrowly triangular, 4-6 mm long, 1-1.5 mm wide, distal margins involute, apex cymbiform; sepals and petals with exterior keeled midrib. Callus absent. Column porrect, 3 mm long, not fused for entire length; filaments and stigma free at distal end. Column foot absent. Pollinia absent. Capsules erect, indehisent, disintegrating when ripe.


Occurs in dense rainforests and wetter types of open forest, usually growing in moist soil close to streams and on sheltered slopes in a range of soil types, sometimes forming loose colonies. Small mycorrhizal tubercles, small fleshy tuber-like growths, are found on the wiry roots. Plants are able to recover following fire by resprouting from the underground stem. Flowering is during the wet season in summer and the flowers are self-pollinating. Fruit takes 8-12 months to develop and ripen.

Locally common.

Flowering period: December-March.


Apostasia has a number of floral features not consistent with Orchidaceae in the strict sense and some authors place the genus in the Apostasiaceae. Genetic studies however place them as a primitive group within the Orchidaceae and they are placed in the subgenus Apostasioideae.

Name Changes

Has been confused with Apostasia wallichii.

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