APIACEAE Carrot Family

1a. Leaves simple

2a. Inflorescence relatively open with pedicellate flowers; leaf blades rounded, not sharply-toothed

Hydrocotyle americana L.

2b. Inflorescence composed of dense, head-like clusters of +/- sessile flowers, each flower subtended by a bractlet; most leaf blades spinulose-toothed

Eryngium planum L.

1b. Leaves compound

3a. Leaves palmately divided; plants with bisexual flowers and unisexual male flowers in separate umbellets or intermixed

Sanicula marilandica L.

3b. Leaves otherwise; plants mostly with male and female flowers in one inflorescence

4a. Larger leaves with ultimate segments narrow-linear to filiform, up to 1.0 mm wide; umbels with 7-14 primary branches

Carum carvi L.

4b. Larger leaves with ultimate segments linear to orbicular, >1.0 mm wide

5a. Leaves with 3 leaflets that are simple or lobed but not again divided

Heracleum L.

5b. Leaves with 5+ ultimate segments

6a. Leaves with clearly defined leaflets, the ultimate segments often >2 cm wide

7a. Principal leaves once-compound (twice-compound in submerged leaves of Sium suave)

8a. Aquatic, fibrous-rooted plants; umbels and umbellets with bracts and bractlets, respectively; flowers white

Sium suave Walter

8b. Taprooted weeds of fields and anthropogenic habitat; flowers yellow

Pastinaca sativa L.

7b. Principal leaves two to three times compound

9a. Petals yellow

10a. Perennial native plants; leaf divisions and leaflets ternately arranged; central flower of each umbellet sessile

Zizia aurea (L.) W.D.J.Koch

10b. Introduced taprooted biennials; leaf divisions and leaflets pinnately arranged; all flowers pedicelled

Pastinaca sativa L.

9b. Petals white

11a. Upper leaf sheaths conspicuously dilated, 1 cm + wide

Angelica L.

11b. Upper leaf sheaths not dilated, < 1 cm wide

12a. Veins of the leaves directed to the sinuses; base of the stem thickened; some of the roots tuberous-thickened; wetland plants

Cicuta maculata L.

12b. Veins of the leaves directed to the teeth; base of the stem not thickened; roots without tubers; plants of more dry habitats

13a. Ovary bristly; plants of rich woods

Osmorhiza Raf.

13b. Ovary glabrous; plants of coastal shores or disturbed areas

14a. Sepals present; styles shorter than the stylopodia, ascending; umbellets with bractlets; plants of coastal shores

Ligusticum scoticum L.

14b. Sepals absent; styles much longer than the stylopodia, deflexed; umbellets lacking bractlets; plants of fields and disturbed areas

Aegopodium podagraria L.

6b. Leaves dissected, without clearly defined leaflets, the ultimate segments often <1 cm wide

15a. Bracts of the umbel pinnatifid; central flower of the inflorescence purple or pink

Daucus carota L.

15b. Bracts of the umbel entire or absent; central flower of the inflorescence white

16a. Bractlets narrow-ovate, with conspicuously ciliate or fimbriate margins

Anthriscus sylvestris (L.) Hoffm.

16b. Bractlets absent or linear to lanceolate, their margins entire or minutely fringed with fine hairs

17a. Axils of upper leaves with bulblets

Cicuta bulbifera L.

17b. Axils of upper leaves without bulblets

Conioselinum chinense (L.) Britton, Sterns & Poggenb.

Angelica L.

1a. Involucels to 1 mm wide, persistent, often reddish margined; fruit only slightly flattened with thick corky dorsal ribs scarcely differing from lateral ribs; plants strictly coastal

A. lucida L.

1b. Involucels inconspicuous, less than 0.5 mm wide, deciduous; fruit strongly flattened with broadly winged lateral ribs and low dorsal ribs; plants not strictly coastal

2a. Inflorescence flat-topped; uppermost leaf sheaths +/- tubular, veins inconspicuous; pedicels finely scabrous; fruit cross-section showing 1-3 oil tubes in each interbal between ribs, seed closely attached to outer coat

A. sylvestris L.

2b. Inflorescence +/- spherical; uppermost leaf sheaths inflated, veins conspicuous; pedicels heavily scabrous; fruit cross-section showing 25-30 oil tubes surrounding the loose seed

A. atropurpurea L.

Heracleum L.

1a. Rays of the uppermost umbels very numerous and conspicuous (50-150); plants often to 4 m tall

Heracleum mantegazzianum Sommier & Levier

1b. Rays fewer, mostly 15-30; plants usually < 3 m tall

Heracleum maximum W.Bartram

Osmorhiza Raf.

Osmorhiza berteroi DC. is not recorded by Erskine (1960) but listed for PEI in North American Flora files at the New York Botanical Garden (Kartesz and Meacham 1999). We consider it unconfirmed but possible.

1a. Styles at most 1.5 mm long; flowers usually 4-8 per umbellet

Osmorhiza claytonii (Michx.) C.B.Clarke

1b. Styles at least 2 mm long; flowers usually 9-18 per umbellet

Osmorhiza longistylis (Torr.) DC.