Pastinaca sativa L.

Parsnip

Pastinaca_sativa_plant.jpg
STATS

Introduced
CC = *
CW = 5
MOC = 48

© SRTurner

Family - Apiaceae

Habit - Biennial forb.

Stem - Ascending or erect, to 2 m, relatively stout, usually strongly ridged, glabrous to moderately short-hairy.

Pastinaca_sativa_stem.jpg Stem and node.

© SRTurner

Leaves - Alternate and often also basal (a few basal leaves usually present at flowering), glabrous or the undersurface short-hairy, short- to long-petiolate, the sheathing bases of lower leaves slightly to moderately inflated. Blades of the basal and main leaves 5-55 cm long (uppermost leaves usually highly reduced and nearly bladeless), oblong-elliptic to ovate in outline, pinnately 1 or 2 times compound, the leaflets 10-200 mm long, lanceolate or ovate to nearly circular, narrowed to less commonly shallowly cordate at the base, toothed (often coarsely so) and often shallowly to deeply lobed, rounded or narrowed to a blunt point at the tip.

Pastinaca_sativa_leaf1.jpg Leaf (adaxial).

© DETenaglia

Pastinaca_sativa_leaf2.jpg Leaf (abaxial).

© DETenaglia

Pastinaca_sativa_sheath.jpg Petiole sheath.

© SRTurner

Pastinaca_sativa_leaflet1.jpg Leaflet adaxial.

© SRTurner

Pastinaca_sativa_leaflet2.jpg Leaflet abaxial.

© SRTurner

Pastinaca_sativa_rachis.jpg Rachis and leaflet bases.

© SRTurner

Inflorescences - Terminal and axillary, compound umbels, these sometimes appearing in loose clusters of 3 or 5, short- to long-stalked, the stalks glabrous or minutely hairy. Involucre absent. Rays 5 to numerous, 2-10 cm long, unequal in length, glabrous or minutely hairy. Involucel absent.

Pastinaca_sativa_involucre.jpg Main umbel.

Involucre absent.

© SRTurner

Pastinaca_sativa_involucel.jpg Umbellet.

Involucel absent.

© SRTurner

Florets - Flowers 8 to numerous in each umbellet, the stalks 2-10 mm long (the central flower sometimes sessile), elongated slightly at fruiting, glabrous or minutely hairy. Sepals absent. Petals 5, ovate, narrowed or tapered to a short, slender tip, this often curled inward, yellow, occasionally tinged with red. Stamens 5, the filaments free. Pistil 1 per flower, composed of 2 fused carpels, the ovary glabrous, inferior with a swollen nectar disc at the tip, the styles 2, often expanded at the base.

Pastinaca_sativa_florets.jpg Florets.

© SRTurner

Fruits - Schizocarps 5-7 mm long, oblong-elliptic or broadly elliptic to slightly oblong-obovate in outline, flattened dorsally, glabrous, tan to light greenish brown with usually prominent reddish brown oil tubes between the ribs, each mericarp with the intermediate and dorsal ribs slender and nervelike, hardly raised from the surface, the lateral ribs with thin, broad wings.

Pastinaca_sativa_fruits.jpg Fruits.

© SRTurner

Flowering - May - October.

Habitat - Pastures, roadsides, fields, railroads, open disturbed areas.

Origin - Native to Europe.

Lookalikes - None close.

Other info. - This is the species of the common culinary parsnip. It is an introduced species in Missouri, found growing wild predominantly in the northern half of the state. It occurs sporadically across the continental U.S. but is much more common in the upper Midwest and New England. It is easily recognized by its robust stature and habit, umbels of yellow flowers, and distinctive leaves.

The roots of the cultivated parsnip are edible and delicious, if harvested in the winter after the first year of growth. However, great care should be taken when handling the wild form of the plant, as the sap contains furanocoumarins which are photoreactive. In sensitive individuals, these compounds can cause serious photodermatitis, resulting in severe blistering of the skin, as if badly burned. Affected areas can remain discolored and abnormally sensitive for up to two years. The furanocoumarin content is highest in the buds and seeds of the wild (non-cultivated) parsnip, possibly because these compounds inhibit herbivory and thus confer a competitive advantage. It is unclear whether the roots of the wild form are suitable for human consumption. In addition to furanocoumarins, the plants also contain polyacetylenes, which are potentially toxic.

Photographs taken at Gallatin Conservation Area, Daviess County, MO, 06-13-2014, and Chloe Lowry Marsh Natural Area, Mercer County, MO, 06-17-2018 (SRTurner).