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Published In: Species Plantarum 1: 256. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/26/2009)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native

 

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1. Cicuta maculata L. (common water hemlock, spotted cowbane)

Pl. 205 a, b; Map 849

Plants perennial, glabrous, often glaucous, with at least some of the main roots tuberous-thickened. Stems 50–200 cm long, erect or ascending, sometimes purple-spotted or mottled toward the base, the base usually somewhat thickened, hollow but cross-partitioned into chambers. Leaves alternate and sometimes also basal (1 or few basal leaves sometimes present at flowering), the basal and lower stem leaves mostly long-petiolate, the median and upper leaves short-petiolate to nearly sessile, at least the lowermost sheathing bases not or only slightly inflated. Leaf blades 2–40 cm long, broadly ovate to triangular-ovate in outline, those of the basal and lowermost stem leaves 2 or 3 times pinnately compound, the ultimate leaflets 20–120 mm long, narrowly lanceolate to oblong-lanceolate, narrowed or tapered at the base, finely to coarsely toothed along the margins, occasionally with 1 or 2 basal lobes, the margins usually also roughened with minute teeth, the main lateral veins mostly ending in the sinuses between the teeth; those of the median and upper leaves progressively reduced, 1 or 2 times pinnately compound, the uppermost occasionally simple, the leaflets similar to those of the lower leaves. Inflorescences terminal and axillary, compound umbels, mostly long-stalked. Involucre absent or less commonly of 1–4 bracts, these shorter than the rays, spreading to ascending at flowering, linear, with sharply pointed tips. Rays usually numerous, 1.5–6.5 cm long, often unequal in length. Involucel absent or more commonly of 3–7 bractlets, these mostly shorter than the flower stalks, linear to broadly lanceolate, with thin, white, papery margins, tapered to sharply pointed tips. Flowers mostly numerous in each umbellet, the stalks 2–10 mm long. Sepals minute triangular teeth. Petals obovate, narrowed abruptly to a slender, pointed extension at the tip, white. Ovaries glabrous. Fruits 2.0–4.5 mm long, broadly oblong-elliptic in outline, flattened laterally, glabrous, dark brown to reddish brown with pale ribs, the mericarps with 5 ribs, these blunt and somewhat corky. 2n=22. May–September.

Scattered nearly throughout the state (U.S., Canada, Mexico). Sloughs, banks of streams, rivers, and spring branches, margins of ponds and lakes, bottomland prairies, moist depressions of upland prairies, and openings of bottomland forests; also roadsides, railroads, and ditches.

Cicuta maculata is perhaps the most poisonous of all North American plants. Although all parts are toxic, the tuberous roots, swollen lower stems, and new growth are considered the most poisonous parts of the plants. The active compounds, a series of polyacetylenes (including cicutoxin and cicutol), are quite different from the alkaloids found in Conium and produce much more violent symptoms. Ingestion of a walnut-sized portion of the root has been suggested as sufficient to kill an animal the size of a cow.

In his revision of Cicuta in North America, Mulligan (1980) recognized four varieties of C. maculata, two of which were reported for Missouri. These are differentiated mainly based on differences in details of fruit morphology, and flowering specimens from Missouri cannot be determined below the species level. Thus, the distributions listed below for var. bolanderi and var. maculata are relatively inexact. A third variety, var. angustifolia Hook., is unique in its subglobose fruits, shorter styles (mostly less than 1 mm), and median and upper leaves with narrower main leaflets (more than 5 times as long as wide). It is widely distributed to the west of the state but has been collected in southeastern Kansas and eventually may be found in Missouri. The other variety, var. victorinii (Fernald) B. Boivin, occurs mostly in the Pacific Northwest and has ribless fruits.

 

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1 1. Mericarps with the dorsal and intermediate ribs much narrower than the space between the ribs, narrowed along the commissures ... 1A. VAR. BOLANDERI

Cicuta maculata var. bolanderi
2 1. Mericarps with the dorsal and intermediate ribs wider than to about as wide as the space between the ribs, not narrowed along the commissures ... 1B. VAR. MACULATA Cicuta maculata var. maculata
 


 

 
 
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