- Written also: Viper’s-grass
- Family: Daisy Family – Compositae, subfamily Cichorioideae (formerly Chicory Family – Cichoriaceae)
- Growing form: Perennial herb. Taproot strong.
- Height: 20–30 cm (8–12 in.). Sometimes many-branched. Stem usually unbranched, white-haired.
- Flower: Single flower-like capitula 5–6 cm (2–2.4 in.) broad, surrounded by involucral bracts. Capitulum flowers pale yellow, often slightly purplish, tongue-like, tip 5-toothed. Stamens 5. Gynoecium composed of 2 fused carpels. Involucral bracts in many rows, different lengths, outermost triangular, soft, soft-haired, green, inner bracts linear, narrowly membranous margins. Capitulum solitary terminating stem.
- Leaves: In basal rosette and alternate on stem. Basal leaves long-stemmed, stalk narrowly winged, grooved, densely haired, stem leaves stalkless, base also with bladeless leaf-sheath. Blade lanceolately elliptic–narrowly lanceolate, tapered, with entire margins, parallel-veined, with white tomentum when young, later more-or-less glabrous.
- Fruit: Round, glossy-ridged, brown, 7–11 mm (0.28–0.44 in.) long achene, crowned with feathery hairs.
- Habitat: Esker woods, forest clearings, grassy forest margins, culturally-influenced meadows, meadow slopes, roadsides.
- Flowering time: June–July.
Viper’s grass spread after the Ice Age from both the south and the west. Stands that have arrived from different directions are still separate and the changes in habitat have been modest by human standards. The species is found in the Åland Islands and in the province of Uusimaa, and its core area is the esker pine forests and forest margins of the Lohja region. Human activity is not much of a threat to the species, and in fact it is often able to take advantage of logging in the forest and the construction of forest roads as they provide more suitable, light-filled habitats. In places the species has even spread to roadsides and railway embankments.
People have exploited viper’s grass too: its sturdy taproot is tasty and good to eat. Instead of starch it contains inulin, which has a minimal affect on blood sugar and is thus excellent for diabetics. It is of the same family as black salsify (S. hispanica), which is a more familiar vegetable. Both species contain a lot of latex, so the pale flesh goes dark soon after being cut. Viper’s grass would be expected to stand out in esker pine forests, but it can easily go unnoticed because it often remains as a leaf rosette. The rosette is slightly reminiscent of ribwort plantain (Plantago lanceolata), but the large capitula that open in May reveal the plant as a member of the Chicory subfamily.