Inula

Linnaeus

Sp. Pl. 2: 881. 1753. 1753

,

Gen. Pl. ed. 5, 375. 1754. 1754

Etymology: Greek inaein, to clean, alluding to medicinal effects or Latin inula, an ancient name for elecampane
Treatment appears in FNA Volume 19. Treatment on page 473. Mentioned on page 40, 471, 474.

Perennials [annuals], 20–200 cm. Leaves basal (usually withering before flowering) and cauline; petiolate (proximal) or sessile (distal); blade margins usually serrate to dentate, sometimes entire. Heads radiate [disciform, discoid], borne singly or in open, corymbiform arrays. Involucres hemispheric or campanulate, [5–]10–40 mm diam. Phyllaries persistent, in 4–7+ series. Receptacles flat or convex, smooth or alveolate, epaleate. Ray florets (15–)50–150+, pistillate, fertile; corollas yellow [orange], laminae 10–30+ mm. Disc florets mostly (50–)100–250+; corollas yellow, lobes 5. Cypselae ± columnar (subterete) or prismatic (± 4–5-ribbed or -angled); pappi persistent, of basally connate, barbellate bristles or setiform scales in 1 series. x = 8, 9, 10.

Distribution

Introduced; Old World.

Discussion

Species ca. 100 (3 in the flora).

The three species in the flora are probably escapes from cultivation. Formerly, Inula was circumscribed more broadly.

Selected References

None.

Key

1 Blades of basal (and proximal cauline) leaves 100–200 mm wide; involucres (20–)30–40 mm diam.; outer phyllaries 6–8(–20+) mm wide Inula helenium
1 Blades of basal (and proximal cauline) leaves mostly 10–30 mm wide; involucres 7–15(–20) mm diam.; outer phyllaries mostly 0.5–2.5 mm wide > 2
2 Blades of cauline leaves lance-elliptic to lance-linear (venation not raised adaxially, reticulation not evident); outer phyllaries 4–6 × 0.5–0.8 mm Inula britannica
2 Blades of cauline leaves broadly elliptic to lanceolate (venation raised adaxially, reticulation prominent); outer phyllaries 5–7 × 1.5–2.5 mm Inula salicina