Corybas Salisb.

Scientific Description

Family Orchidaceae.

Habit and leaf form. Dwarf herbs (colony-forming); deciduous. Plants succulent, or non-succulent. Perennial. Leaves basal. Tuberous (tubers globular, formed at the end of long, slender fleshy roots). Helophytic, or mesophytic. Leaves small to medium-sized; ‘herbaceous’, or leathery, or fleshy; petiolate; simple. Leaf blades entire; flat; ovate to orbicular; parallel-veined; cross-venulate, or without cross-venules; cordate. Leaf blade margins entire. Vernation conduplicate. Leaf anatomy. Hairs absent. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous (small fungal gnats). Pollination mechanism conspicuously specialized (the gnats possibly mistaking the unusual flowers for fruiting bodies of fungi).

Inflorescence and flower features. Flowers solitary. Inflorescences stem bracts absent. Flowers subsessile (within the leaf at anthesis, the stem then elongating up to 30cm to aid seed dispersal); small to medium-sized; fragrant, or odourless; 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; 6, or 2 (by misinterpretation); 2 -whorled; isomerous (but zygomorphic); free; red to purple (with green or white markings). Calyx (if the outer whorl be so designated) 3 (the median member ostensibly posterior), or 4 (by misinterpretation); 1 -whorled; polysepalous. Corolla (i.e. the members of the inner whorl) 3, or 2 (by misinterpretation); polypetalous; imbricate. Androecium 3, or 1 (by misinterpretation). Androecial members free of the perianth; united with the gynoecium (fused with the style to form a column or ‘gynostemium’; column short, thickened under the stigma); 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 4, in 2 pairs). 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, South Australia, New South Wales, Victoria, Australian Capital Territory, and Tasmania. South-West Botanical Province.

Additional characters Perianth of 5 dissimilar members and the median inner member modified into the labellum (the adaxial sepal erect, hood-shaped, adhering to the labellum; lateral sepals and petals linear, greatly reduced (in Western Australian species) or elongated (elsewhere); labellum large, base tubular, enclosing the column, limb closely reflexed on the tube, broad, denticulate or shortly fringed). Leaves solitary. Leaves ground-hugging. Labellum not insect-like. Perianth not glossy. Labellum hairy (hairs short), or without ornamentation.