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The Western Australian Herbarium’s collections management system, WAHerb, and DBCA’s flora taxonomic names application, WACensus, have been set to read-only mode since 1 October 2025. Recent taxonomic changes are not currently being reflected in Florabase, herbarium collections, or the census. Due to the rapidly approaching holiday season and associated agency and facility soft closures, along with the substantial work involved in data mapping, cleaning, and verification, the migration to the new collection management software is not expected to occur before 1 March 2026, when a further update will be provided. Please reach out to us if you have any questions or concerns.

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Epilobium L.

Reference
Sp.Pl. [Linnaeus] 2:347 (1753)
Name Status
Current

Scientific Description

Common name. Willow Herb. Family Onagraceae.

Habit and leaf form. Herbs; bearing essential oils, or without essential oils. Annual, or perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Hydrophytic, or helophytic, or mesophytic. Leaves alternate, or opposite; when alternate, spiral; petiolate to sessile; non-sheathing; simple; epulvinate. Leaf blades entire; elliptic, or ovate, or linear; pinnately veined; cross-venulate. Leaves with stipules, or without stipules. Stipules when present, intrapetiolar; free of one another; caducous. Leaf blade margins serrate, or dentate. Leaves without a persistent basal meristem.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers solitary; axillary; pedicellate; ebracteolate; small to large; usually regular; 4 merous; cyclic; tricyclic, or tetracyclic, or pentacyclic. Free hypanthium present, or absent; not extending beyond ovary; short but evident if present. Perianth with distinct calyx and corolla; 8; 2 -whorled; isomerous. Calyx present; 4; 1 -whorled; gamosepalous; blunt-lobed; lobes valvate; not persistent. Corolla present; 4; 1 -whorled; polypetalous; imbricate, or contorted; white, or yellow, or red, or pink, or purple. Petals clawed, or sessile. Androecial members definite in number. Androecium 8. Androecial members adnate, or free of the perianth; markedly unequal (the alternisepalous whorl shorter); free of one another; 2 -whorled. Androecium exclusively of fertile stamens. Stamens 8 (in 2 whorls); isomerous with the perianth; alternisepalous and oppositisepalous. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen shed in aggregates, or shed as single grains; with viscin strands, or without viscin strands; if in aggregates, in tetrads. Gynoecium 4 carpelled. The pistil 4 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; inferior. Ovary plurilocular; 4 locular. Epigynous disk present. Gynoecium stylate. Styles 1; apical. Stigmas 1; 1 - lobed, or 4 - lobed; clavate, or capitate. Placentation axile, or parietal. Ovules 1–50 per locule (to ‘many’); pendulous, or ascending; non-arillate; anatropous.

Fruit and seed features. Fruit fleshy, or non-fleshy; dehiscent; a capsule. Capsules loculicidal, or septicidal. Fruit 2–100 seeded. Seeds non-endospermic; conspicuously hairy, or not conspicuously hairy; with a tuft of hairs, or without a tuft of hairs. Cotyledons 2. Embryo straight.

Etymology. From the Greek for "upon" and "pod"; the petals rest on the pod-like ovary.