Herbs, perennial, scapose, forming dome-shaped clumps, from rhizomes; rhizomes short, branching, sometimes stoloniferous, leaf scars prominent; roots fleshy. Leaves numerous, basal, spiral, distinctly petiolate; petiole sulcate, terete, sometimes ridged; blade light to dark green, often variegated, cordate to orbiculate to lanceolate, smooth to puckered, margins entire, slightly undulate [flat or crisped]; veins campylodromous, conspicuous, usually sunken adaxially, prominent abaxially. Scape usually surpassing leaves. Inflorescences simple, terminal, racemose, usually subsecund, elongate, subtended proximally by 1 or more sterile bracts, each flower usually bracteate. Flowers: perianth tubular to campanulate or urceolate-cylindric [funnelform]; tepals 6, similar, connate proximally into wide-throated tube, white, bluish purple, or purplish violet with darker markings or lines, lobes spreading, sometimes recurved, longer than perianth tube; stamens 6, inserted at base of perianth tube or ovary apex, exceeding tepals; filaments declinate; anthers dorsifixed in connective pits, dehiscence introrse; ovary superior, sessile, 3-locular, oblong, septal nectaries present; style filiform, exceeding stamens; stigma minute, capitate or 3-lobed; pedicel short. Fruits capsular, pendent at maturity, angled, elongate or triangular, dehiscence loculicidal. Seeds numerous, black, flattened, winged. x = 30.
Introduced; temperate e Asia, especially Japan, cultivated worldwide.
Species ca. 40 (3 in the flora).
Hosta species delimitation has been problematic due to a long history of cultivation, hybridization, and selection, particularly in Japan, from the eighth century onwards (W. G. Schmid 1991). Hosta nomenclature is further complicated because many names are based on types of garden origin or sports originating among wild populations. Earlier taxonomic treatments were largely based on materials cultivated regionally in Japan (N. Fujita 1976), North America (L. H. Bailey 1930), Korea (M. G. Chung 1990; M. G. Chung and J. W. Kim 1991), and Europe (N. Hylander 1954). Hosta can be considered to comprise as few as 23–26 species (F. Maekawa and K. Kaneko 1968; N. Fujita 1976), or 40 or more if a stricter species concept is applied (A. Huxley et al. 1992; F. Maekawa 1940; W. G. Schmid 1991).
Well over 1000 cultivars have been recorded with the International Registration Authority. Primarily used in temperate shade gardens, these cultivars feature various combinations of leaf size, shape, color, variegation, and texture (P. Aden 1988; D. Grenfell 1996, 1998; N. Hylander 1954; K. Kubitzki 1998b; W. G. Schmid 1991). While Hosta is mainly of ornamental importance economically, the leaves of some species are cooked and eaten in Korea and Japan, thus depleting local populations.
Funkia, a later generic name proposed by Sprengel for these plants, is an illegitimate later homonym of Funckia Wildenow, and the family name Funkiaceae based upon it is therefore invalid (B. Mathew 1988). However, “funkia,” from the vernacular Japanese fukurin fu, long ago passed into many European languages as another common name for Hosta.
|1||Leaf blades light yellowish green; flowers fragrant, to 13 cm, perianth long-tubular; tepals white.||Hosta plantaginea|
|1||Leaf blades green; flowers not fragrant, 4–5.5 cm, perianth tubular-campanulate or urceolate-cylindric; tepals bluish purple or purplish violet.||> 2|
|2||Scape 40–50 cm; leaf blades lanceolate to ovate-lanceolate, 10–17 × 5–7.5 cm, with 5–6 lateral vein pairs; tepals purplish violet; anthers purple.||Hosta lancifolia|
|2||Scape 80–95 cm; leaf blades broadly ovate to cordate, 20–30 × 15–20 cm, with 7–9 lateral vein pairs; tepals bluish purple; anthers spotted purple.||Hosta ventricosa|