Ontario Weeds: Water parsnip
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Leaves
- Flowers and Fruit
- Habitat
- Similar Species
- Caution
- Related Links
Name: Water-parsnip, Sium suave
Walt.,
Other Names: berle douce, berle à
larges feuilles
Family: Carrot Or Parsley Family (Umbelliferae)
General Description: Perennial, reproducing
only by seed. Roots coarsely fibrous or cord-like (A) but never
tuberous.
Photos and Pictures
Water parsnip. A.Base of plant.
B. Top of flowering stem. C. Much dissected submerged leaf.
Stems & Roots: Roots coarsely
fibrous or cord-like but never tuberous. Stems erect, 60-200cm (2-6½ft)
high, branching above, hollow except for a partition at each node.
Leaves: Leaves alternate (1 per node),
pinnately compound with usually 5 to 15 leaflets, these arranged
in 2 to 7 pairs of opposite leaflets along the leaf axis (rachis)
plus 1 terminal leaflet, the base of the leafstalk broad, thin-winged
and encircling the stem at the node, leaflets variable in shape
from very narrow and linear to lance-shaped but always sharply saw-toothed;
basal leaves growing submerged in water are 2 or more times pinnately
divided and quite unlike the stem leaves which grow above the water
surface.
Flowers & Fruit: Flowers individually
very small, white, in compound umbels [1 large umbel made up of
several small umbels] varying 3-12cm (1¼-4½in.) across,
with several, narrow, pointed bracts at the base of each large umbel;
fruits (pairs of "seeds") oval, 2-3mm (1/12-1/8in.) long.
Flowers from July to September.
Habitat: Water-parsnip is a native
plant throughout Ontario and grows in low wet areas, often in standing
water as deep as 1m (40in.). Water-parsnip has been reported to
be poisonous to livestock and, although experimental feeding trials
have not proven it to be harmful, livestock growers should be cautioned
against the potential danger of this native plant.
Similar Species: It is distinguished from
Water-hemlock, known to be very poisonous, by its stem leaves above
the water surface being once-pinnately compound, its several thin
bracts at the base of each compound umbel, its numerous thin or
cord-like roots at the base of each stem, and by the absence of
well-defined cross-partitions in the base of the stem which are
characteristic of Spotted water-hemlock.
Caution: Circumstantial evidence suggests
that Water-parsnip may be poisonous to hogs and cattle so it must
be regarded with suspicion.
Related Links
... on general Weed
topics
... on weed identification, order OMAFRA
Publication 505: Ontario Weeds
... on weed control, order OMAFRA
Publication 75: Guide To Weed Control
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