Eriochilus R.Br.
Bunny Orchids

Scientific Description

Family Orchidaceae.

Habit and leaf form. Herbs. Plants succulent (some species with fleshy stems and leaves), or non-succulent. Perennial. Leaves basal (sometimes sheathing the lower part of the stem so that the blade appears to be cauline), or cauline (by misinterpretation). Tuberous (tuber succulent). Helophytic, or mesophytic. Leaves minute to medium-sized; ‘herbaceous’, or leathery, or fleshy; petiolate; simple. Leaf blades entire; flat; parallel-veined; cross-venulate, or without cross-venules. 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. Floral nectaries present. Entomophilous (small bees). Pollination mechanism conspicuously specialized (the flowers, in some species producing nectar, are pollinated as the bees probe with extended mouth parts between the tightly appressed column and labellum).

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’. Inflorescence 1–10 (or more) flowered. Flowers loose. The terminal inflorescence unit racemose. Inflorescences scapiflorous, or not scapiflorous; terminal; stem bracts absent. Flowers pedicellate; 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; 2 -whorled; isomerous (but zygomorphic); free; sepaloid and petaloid; without spots, or spotted (on labellum only); white, or pink. 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 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 with broad slit-like 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 or 8). 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. Endemic to Australia. Australian states and territories: Western Australia, South Australia, Queensland, 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 (adaxial sepal erect, contracted in the lower part; lateral sepals clawed, spreading, longer than the other perianth segments, acute; lateral petals narrow, inconspicuous; labellum with a long claw, strongly recurved). Leaves solitary. Leaves erect (usually), or ground-hugging (in E. tenuis and E. scaber). Perianth not glossy. Labellum hairy.