Hemlock Parsley is a perennial herb with simple stems which are 3-10 dm high and arise from a club-shaped taproot or cluster of fleshy roots and a simple or little-branched rootcrown. The alternate leaves are divided into 7-11 leaflets, the lower of which are divided 2-3 more times. The leaves are triangular in outline and 3-19 cm long with a 3-23 cm long petiole and a dilated sheath at the base. Ultimate leaf segments are less than 3 mm wide. The foliage is glabrous below the inflorescence. Small, white flowers occur in hemispherical clusters borne at the ends of 9-15 stalks, which are arranged in an umbrella-shaped inflorescence, or umbel; the umbel is 3-10 cm in diameter and is located at the top of the stems. Each cluster of flowers is subtended by 3-6 thread-like bracts, which comprise an involucre that is 2-8 mm long. The flattened, egg-shaped fruits are 4-6 mm long and have corky, thickened margins and a conspicuous thickening at the top at the base of the style, known as a stylopodium.
Fruiting in July.
Whether by name or look, several members of the Apiaceae (Carrot or Parsley) Family can be look-a-likes. These plants are not ones to mis-identify because some are toxic or poisonous. Be conscious of your safety when examining plants. Hemlock Parsley can be distinguished from
Ligusticum species by the involucre of 3 or more bracts and by the lack of stringy old leaf bases at the top of the root crown.
Hemlock Parsley -
Conioselinum scopulorum, origin and presence unknown
* Plants: Sparsely hairy (glabrate).
* Stems: Single but sparingly branched and hollow. Lower portion not purple-spotted. Petioles are basally dilated. Base is not swollen.
* Leaves: Glabrate, bi- to tri-pinnately divided. Ultimate leaf lobes with one main vein. No bulbs in leaf axils.
* Flowers: White. Sepals absent.
* Mericarps: Glabrous. Elliptical. Dorsal ribs narrowly winged, low and corky. Marginal (lateral) ribs winged.
* Roots: Tuberous and fibrous.
* Habitats: Moist meadows, woodlands, streambanks, and wetlands.
Poison Hemlock -
Conium maculatum, non-native
* Plants: Highly poisonous. Hairs absent (glabrous).
* Stems: Lower portion is purple-spotted. Base is little, to not, swollen.
* Leaves: Glabrous and tri-pinnately divided into small ultimate segments; fern-like. Veins meet with tip of the leaf's tooth. No bulbs in leaf axils.
* Flowers: White. Sepals absent.
* Mericarps: Glabrous, prominent ribs raised, but barely winged and often wavy.
* Roots: Stout taproot.
* Habitats: Moist, disturbed places, such as along streams, ditches, and cool open slopes.
Queen Anne's Lace or Wild Carrot -
Daucus carota, non-native
* Plants: Hairs sparse (glabrate) to long and stiff (hirsute).
* Stems: Lower portion not purple-spotted. Base is not swollen.
* Leaves: Glabrous and bi-pinnately divided with leaflets being deeply divided. No bulbs in leaf axils.
* Flowers: White with the central flower of the central umbel often purple. Sepals minute.
* Mericarps: Ribs with barbed prickles (not glabrous).
* Roots: Stout taproot.
* Habitats: Along roads, trails, and in fields – often in areas with some disturbance.
Western Water-hemlock -
Cicuta douglasii, native
* Plants: Highly poisonous. Hairs absent (glabrous).
* Stems: Often branched. Lower portion not purple-spotted. Base is swollen.
* Leaves: Glabrous. Bi- to tri-pinnately divided. Tertiary venation twice as long as wide and enclosing sections of the leaflets. Primary lateral veins terminate in the sinuses between the serrations (teeth). No bulbs in leaf axils.
* Flowers: white or greenish.
* Mericarps: Glabrous. Prominent ribs are corky (at least as wide as the darkened intervals), but not winged.
* Roots: Thickened or tuberous. Internally are horizontally divided with cross partitions.
* Habitats: Moist meadows, streambanks, and wetlands.
Spotted Water-hemlock -
Cicuta maculata, native
* Plants: Highly poisonous. Hairs absent (glabrous).
* Stems: Often branched. Lower portion not purple-spotted. Base is swollen.
* Leaves: Glabrous and bi- to tri-pinnately divided. Tertiary venation of the leaflet is as long as wide. Primary lateral veins terminate in the sinuses between the serrations (teeth). No bulbs in leaf axils.
* Flowers: White or greenish.
* Mericarps: Glabrous. Prominent ribs are corky (at least as wide as the darkened intervals), but not winged.
* Roots: Thickened or tuberous. Internally are horizontally divided with cross partitions.
* Habitats: Moist meadows, woodlands, streambanks, and wetlands.
Bulb-bearing Water-hemlock -
Cicuta bulbifera, native
* Plants: Highly poisonous. Hairs absent (glabrous).
* Stems: Usually solitary. Lower portion not purple-spotted. Base is swollen.
* Leaves: Glabrous. Upper leaves are simple or once-pinnate with bulblets in the axils.
* Flowers: White. Often sterile.
* Mericarps: Ribs thick and raised, wider than the intervals.
* Roots: Thickened or tuberous.
* Habitats: Fens.
Hemlock Water-parsnip -
Sium suave, native
* Plants: Hairs absent (glabrous).
* Stems: Solitary. Lower portion not purple-spotted. Base is not swollen.
* Leaves: Glabrous. Emergent leaves are once-pinnate with lance-linear leaflets. Submerged leaves are bi- to tri-pinnately divided with narrower leaflets. Primary lateral veins sometimes terminate in the tips of the serrations (teeth). No bulbs in leaf axils.
* Flowers: White or greenish. Sepals minute.
* Mericarps: Glabrous and elliptical. Ribs corky, but not winged.
* Roots: Fibrous. Internally are horizontally divided with cross partitions.
* Habitats: In shallow fresh water and banks of streams, ponds, and wetlands.
Cow-Parsnip -
Heracleum lanatum, native
* Plants: Hairs present.
* Stems: Single, hollow, with short, soft hairs (pubescent). Lower portion not purple-spotted. Base is not swollen.
* Leaves: Veins pubescent. Leaves once-palmately divided into 3 leaflets. Leaflets broad, 3-7 lobed, and coarsely toothed. Petioles are basally dilated. No bulbs in leaf axils.
* Flowers: White and sweet-smelling. Sepals minute.
* Mericarps: Glabrous. Obovate. Dorsal ribs narrow. Marginal (lateral) ribs broadly winged.
* Roots: Stout taproot.
* Habitats: Moist places, such as avalanche slopes, thickets, open forests, woodlands, along streams, and drier wetlands.
Riparian forests and moist meadows in the valleys.
