Pyrorchis D.L.Jones & M.A.Clem.
Phytologia 77:448 (1994)

Name Status: Current
Browse to the list of specimens for Pyrorchis D.L.Jones & M.A.Clem.

Scientific Description
H.R. Coleman, Thursday 8 September 2016

Family Orchidaceae.

Habit and leaf form. Colony-forming herbs (flowering profusely after fire or disturbance). Plants succulent, or non-succulent. Perennial. Helophytic, or mesophytic. Leaves small to medium-sized; when more than 1, alternate, or opposite, or whorled; fleshy; sessile; simple. Leaf blades entire; flat; ovate; parallel-veined; cross-venulate, or without cross-venules. Leaf blade margins entire. Vernation convolute. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous (native bees). Pollination mechanism conspicuously specialized.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’. Inflorescence few-flowered. Flowers in racemes. The terminal inflorescence unit racemose. Inflorescences scapiflorous, or not scapiflorous; terminal. Flowers pedicellate; small to medium-sized (opening widely for long periods); 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; 6; 2 -whorled; isomerous (but zygomorphic); free; dull-coloured, pink and white, or red and white. 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; 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 narrow, incurved, without a foot); 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). Gynoecium 3 carpelled. The pistil 1 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; inferior. Styles tubers ovoid, daughter tubers produced at apex of long stoloniferous roots. 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, New South Wales, Victoria, and Tasmania. South-West Botanical Province.

Additional characters Perianth of 5 similar members and the median inner member modified into the labellum (sepals and lateral petals of similar length and colour; adaxial sepal broader than lateral sepals, hooded; labellum free, not clawed, hinged to the base of the column, 3-lobed; mid-lobe short, margins crenulate or lacerate; lamina callus consisting of a central plate-like ridge, breaking up distally into irregular calli). Leaves solitary, or not solitary (to 3-leaved). Leaves ground-hugging. Column not prominently winged (vestigial wings narrow, adnate). Perianth not glossy.

Taxonomic Literature

  • Wheeler, Judy; Marchant, Neville; Lewington, Margaret; Graham, Lorraine (2002). Flora of the south west, Bunbury, Augusta, Denmark. Volume 1, introduction, keys, ferns to monocotyledons. Australian Biological Resources Study. Canberra.
  • Hopper, Stephen D.; Brown, Andrew P. (2001). Contributions to Western Australian orchidology. 1, history of early collections, taxonomic concepts and key to genera.
  • Jones, David L.; Clements, Mark A. (1996). Pyrorchis, a new genus of Orchidaceae from Australia.
  • Brown, Andrew; Hoffman, Noel (1995). Orchids of south-west Australia. University of W.A. Press. Nedlands, W.A.