Habit and leaf form. Herbs. Plants succulent, or non-succulent. Perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves; stems short and pseudobulbous or elongated without pseudobulbs and continuing to grow for several years, covered by leaf bases. Epiphytic, or self supporting (occasionally, in extra-Australian species). Helophytic, or mesophytic, or xerophytic. Leaves medium-sized to very large; alternate; spiral, or distichous; ‘herbaceous’, or leathery, or fleshy; imbricate; petiolate; simple. Leaf blades entire; flat; more or less linear (channelled or slightly concave above); parallel-veined; cross-venulate, or without cross-venules. Leaf blade margins entire. Vernation conduplicate. Stem anatomy. Secondary thickening absent. Roots. Roots with velamen (in epiphytic forms), or without velamen.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous (small native bees). Pollination mechanism conspicuously specialized.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence few-flowered to many-flowered. Flowers in racemes. The terminal inflorescence unit racemose. Inflorescences scapiflorous, or not scapiflorous; arising from base of pseudobulb or near lower leaves, becoming pendulous. Flowers small to large; fragrant; very irregular; zygomorphic; resupinate. The floral asymmetry involving the perianth and involving the androecium. Flowers 3 merous; cyclic; supposedly basically pentacyclic. Perigone tube absent. Perianth of ‘tepals’, or with distinct calyx and corolla, or petaline (by misinterpretation); 6; 2 -whorled; isomerous (but zygomorphic); free; without spots, or spotted; green, or brown, or purple, or red. Calyx (if the outer whorl be so designated) 3 (the median member ostensibly posterior); 1 -whorled; polysepalous. Corolla (i.e. the members of the inner whorl) 3, or 6 (by misinterpretation); polypetalous; imbricate. Androecium 3, or 1 (by misinterpretation). Androecial members adnate (via fusion of the labellum and column foot); united with the gynoecium (fused with the style to form a column or ‘gynostemium’; column rather long); coherent (via the gynostemium); 1 - adelphous; theoretically 2 -whorled. Androecium including staminodes, or exclusively of fertile stamens (by misinterpretation). Staminodes 2 (these anterior (ostensibly posterior), supposedly the abaxial pair of the inner whorl). Stamens 1 (this across the flower from the labellum, i.e. anterior but ostensibly posterior, supposedly representing the outer whorl); reduced in number relative to the adjacent perianth; alterniperianthial (i.e. with reference to the single stamen, across the flower from the labellum); filantherous, or with sessile anthers. Anthers dorsifixed to basifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate; appendaged, or unappendaged. Pollen shed in aggregates; in the form of pollinia (pollinia 2, cleft). Gynoecium 3 carpelled. The pistil 1 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary unilocular; 1 locular. The ‘odd’ carpel anterior (away from the labellum). Gynoecium stylate. Styles 1 (inflexed); apical. Stigmas 1; 3 - lobed (but becoming much modified in form, the apex of the median lobe forming the ‘rostellum’); wet type; papillate; Group III type. Placentation parietal. Ovules not differentiated; in the single cavity 30–100 (i.e. very numerous); non-arillate; anatropous.
Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules septicidal, or loculicidal. Fruit 30–500 seeded (i.e. seeds usually very numerous). Seeds endospermic (endosperm development arrested very early), or non-endospermic; minute; without starch. Embryo rudimentary at the time of seed release, or weakly differentiated. Seedling. Seedling collar not conspicuous. Primary root ephemeral.
Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales. Northern Botanical Province.
Additional characters Perianth of 5 similar members and the median inner member modified into the labellum (sepals and lateral petals usually similar; labellum small, adnate to the very short column foot, 3-lobed but sometimes the lobing indistinct; lateral lobes erect and close to column; throat of labellum with 1 or 2 keels, sometimes indistinct, often modified). Leaves not solitary. Leaves erect. Perianth not glossy.