Eschscholzia Cham.
Horoae Phys.Berol. p73, t. 15. (1820)

Name Status: Current
Browse to the list of specimens for Eschscholzia Cham.

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

Family Papaveraceae.

Habit and leaf form. Herbs; non-laticiferous and without coloured juice (with watery juice). Annual to perennial (often with a stout taproot); plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Mesophytic. Leaves alternate; spiral; slightly fleshy; more or less petiolate (on the whole plant); non-sheathing; simple. Leaf blades dissected; much-divided (deeply bipinnatisect); pinnately veined; cross-venulate. Leaves without stipules; without a persistent basal meristem. Leaf anatomy. Hydathodes present, or absent. Stem anatomy. Nodes unilacunar, or tri-lacunar. Secondary thickening absent, or developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; in cymes and in racemes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal. Flowers medium-sized, or large; operculate (calyptrate), or not operculate; odourless; 2 merous; tetracyclic to pentacyclic to polycyclic. Floral receptacle developing an androphore, or developing a gynophore, or with neither androphore nor gynophore. Free hypanthium present; sometimes with conspicuous spreading rim. Hypogynous disk absent. Perianth with distinct calyx and corolla; 6; 3 -whorled; isomerous. Calyx 2; 1 -whorled; gamosepalous; entire; calyptrate; imbricate; regular; not persistent (caducous). Corolla 4; 2 -whorled (2+2); polypetalous; imbricate and crumpled in bud; regular; white, or yellow, or orange; not spurred. Androecium 50–100 (i.e. ‘many’). Androecial sequence determinable, or not determinable. Androecial members maturing centripetally; free of the perianth, or adnate (often adhering to base of petals); free of one another; 3–15 -whorled (? generally indefinite in 2- or 3-merous, regularly alternating whorls). Androecium exclusively of fertile stamens. Stamens 50–100 (i.e. ‘many’); polystemonous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; tetrasporangiate. Pollen shed in aggregates, or shed as single grains; in tetrads. Gynoecium 2 carpelled. The pistil 1 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; synstylovarious; superior. Ovary unilocular; 1 locular. Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium transverse; non-stylate, or stylate (then style short). Styles 1; simple (short); persistent. Stigmas 2, or 4; dorsal to the carpels, or commissural, or dorsal to the carpels and commissural; thread-like; dry type; papillate; Group II type. Placentation parietal. Ovules in the single cavity 20–50 (i.e. ‘many’); horizontal, or ascending; with superior or lateral raphe; arillate, or non-arillate; anatropous, or campylotropous, or amphitropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule (ellipsoid, ribbed). Capsules dehiscing explosively via 2 acropetal valves along the whole length. Fruit many-seeded. Seeds spherical to ellipsoid to obovoid; copiously endospermic. Endosperm oily. Seeds arillate. Embryo rudimentary at the time of seed release, or weakly differentiated. Cotyledons 2. Testa reticulately patterned. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C3.

Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, and Victoria. South-West Botanical Province.

Economic uses, etc. Cultivated as ornamentals.

Taxonomic Literature

  • Wheeler, Judy; Marchant, Neville; Lewington, Margaret; Graham, Lorraine (2002). Flora of the south west, Bunbury, Augusta, Denmark. Volume 2, dicotyledons. Australian Biological Resources Study. Canberra.
  • Grieve, B. J.; Blackall, W. E. (1998). How to know Western Australian wildflowers : a key to the flora of the extratropical regions of Western Australia. Part II, Dicotyledons (Amaranthaceae to Lythraceae). University of W.A. Press. Nedlands, W.A.