Thallus of Kallymenia tasmanica foliose, entire or lobed but not perforated, usually about as broad as tall. Blades delicate, mucilaginous, lobed with uneven, undulate margins, Marginal lobes that are often overlapping and themselves lobed Holdfast discoid. Medulla including many-armed isodiametric cells and stellate cells, which can contain refractive material. Cortex thin. Cortical cells having equal diameters, progressively smaller toward cuticle. Plants pink red in colour.