Heracleum

Scientific name

Heracleum L.

Common names

cow parsley, cow parsnip, hogweed, cow persicum

Family

Apiaceae

Similar genera

Cicuta, Sium

Native distribution

mainly southern Russia and southwest Asia, also North America and east Africa

Species cultivated

Heracleum lanatum Michx.

H. maximum W. Bartram

H. sosnowskyi Manden.

U.S. Federal Noxious Weed: Heracleum mantegazzianum

Identification: Vegetatively similar to H. maximum, but differs in size (3.0-4.5 meters tall), compoundcompound:
(adj) with two or more like parts, as in a compound leaf; divided into two or more subsidiary parts or orders, as in a compound inflorescence
leaves 100-150 cm wide with deeply incised margins, stems 3-8 cm in diameter with extensive purple mottling, and an umbelumbel:
(n) a flat to convex inflorescence in which the flower pedicels (called rays) all arise from the same point
80-100 cm in diameter with 50-150 flower rays.

See Heracleum mantegazzianum disseminule fact sheet.

Adventive distribution

Heracleum mantegazzianum Sommier & Levier and H. sosnowskyi have been introduced into Europe. H. mantegazzianum is also introduced into North America, Australia, and New Zealand.

Weed status

Heracleum sosnowskyi and H. mantegazzianum are weedy in several countries. H. mantegazzianum is a terrestrialterrestrial:
(adj) growing on land as opposed to living in water
weed on the U.S. federal noxious weeds list.

Habit

large, amphibiousamphibious:
(adj) of a plant able to live on land or in water
to wetland obligate herb

Brief description

Stem erect, branched, often ribbed or striate, typically pubescentpubescent:
(adj) (1) covered with short, soft hairs; (2) bearing hairs
, often with dark reddish-purple spots. Leaves alternatealternate:
(adj) (of leaves) bearing one leaf per node; placed singly on the stem at different heights
, ternately or pinnately compoundcompound:
(adj) with two or more like parts, as in a compound leaf; divided into two or more subsidiary parts or orders, as in a compound inflorescence
; basalbasal:
(adj) at or pertaining to the base, or point of attachment
and lower leaves long-petioled, upper leaves and petioles gradually reduced; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
ovate to oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
; marginmargin:
(n) edge; rim
lobedlobed:
(adj) divided into (usually rounded) segments
, crenatecrenate:
(adj) (of a margin) with shallow, rounded teeth
to serrateserrate:
(adj) (of a leaf margin) bearing sharp teeth pointing forward or to the apex
. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
an axillaryaxillary:
(adj) in, of, or produced from an axil
and terminalterminal:
(adj) at the apex
compoundcompound:
(adj) with two or more like parts, as in a compound leaf; divided into two or more subsidiary parts or orders, as in a compound inflorescence
umbel; pedunculatepedunculate:
(adj) borne on or possessing a peduncle
; bracts absent or few, typically linear and deciduousdeciduous:
(adj) shedding of parts at the end of their growing period, as with leaves; those trees or shrubs that drop their leaves at the end of the season
; bracteoles linear or lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
, usually deciduousdeciduous:
(adj) shedding of parts at the end of their growing period, as with leaves; those trees or shrubs that drop their leaves at the end of the season
. Flowers numerous, pedicellatepedicellate:
(adj) borne on a pedicel
; petals 5, white or pinkish, obovateobovate:
(adj) ovate, with the narrow end at the base
or obcordate, with emarginateemarginate:
(adj) with a shallow notch at apex
apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
; outermost flowers often radiant, rays enlarged, typically unequal and pubescentpubescent:
(adj) (1) covered with short, soft hairs; (2) bearing hairs
.

Natural habitat

occurring in a variety of habitats: riparianriparian:
(adj) growing by rivers or streams; of, adjacent to, or living on, the banks of a river, lake, pond, etc.
zones, on flood plains of rivers and lakes, along streams and rivers, alpine meadows, forest margins and artificial habitats (such as wet roadsides)

Additional comments

There are no true aquatics in this genus of about 50 species, only amphibiousamphibious:
(adj) of a plant able to live on land or in water
to wetland obligates. Certain species contain photosensitizing furanocoumarins, which, after contact with skin and exposed to sunlight, can cause rashes, burns, and/or blisters.