in H. G. A. Engler and K. Prantl, Nat. Pflanzenfam. 2[II,5]: 40, plates 17, 18. 1887.
Plants forming open clumps 35–50 × 30 cm; rhizomes sometime stoloniferous. Leaves: petiole erect, green, dotted purple at base, 17–25 cm; blade deep olive green, lanceolate to ovatelanceolate, 10–17 × 5–7.5 cm, apex narrowly acuminate; veins in 5–6 lateral pairs. Scape 40–50 cm. Inflorescences: racemes 10–20-flowered, lax, slender, 17–20 cm; floral bracts short, glossy green, narrowly navicular; sterile bracts 3–5, large, leafy. Flowers 4–4.5 cm, not fragrant; perianth tubular-campanulate; tepals purplish violet, lobes spreading, recurved; anthers purple. Capsules rarely developing (pod sterile). 2n = 60.
Phenology: Flowering late summer–early fall (September).
Habitat: Disturbed open areas
Elevation: 0–300 m
Introduced; Conn., Ill., Md., N.J., N.Y., Ohio, Pa., expected elsewhere, Japan (of garden origin), cultivated worldwide
Hosta lancifolia produces an excellent ground cover with deep olive green leaves and vigorous vegetative growth. Since this species is of ancient horticultural origin and does not occur in the wild, it has been reduced to cultivar status in horticultural nomenclature as Hosta ‘Lancifolia’ (W. G. Schmid 1991).
"thicker" is not a number.