Flora of Bhutan Umbelliferae: Oenanthe

Oenanthe L. Mark F. Watson

Rhizomatous or stoloniferous marshland perennials. Leaves 1–4 x pinnately divided, ultimate segments medium-sized or minute. Umbels compound; bracts absent or few; bracteoles several linear. Calyx teeth small. Petals obovate, with an acute inflexed tip. Stylopodium conical, often hidden by calyx. Fruit ovoid-ellipsoid, glabrous, mericarps unequally ribbed, lateral pair of ribs broader and corky.

Key to species

1	Leaves, simple or sparingly once pinnate, rachis grass-like, segments filiform	*O. hookeri*
+	Leaves biternate or 2–4 x pinnately divided, segments otherwise	2

2	Leaves biternate or bipinnate, leaflets medium-sized, elliptic	*O. javanica*
+	Leaves 3–4 x pinnately divided, ultimate segments numerous, minute, linear	*O. thomsonii*

Oenanthe hookeri C.B.Clarke

Stems fleshy, weakly erect to 100cm long. Leaves 4–20cm, simple or sparingly once pinnate; rachis grass-like, flattened 2–3mm broad; segments up to 3 pairs, linear, 2–25 x 0.5mm, glabrous. Umbels rather few, 3–4cm across, 6–9-rayed; rays 1.5–3cm; bracteoles 2–3mm; umbellules 0.75–1cm across. Calyx teeth c 1mm. Petals white sometimes tinged pink, obovate-spathulate, 1–1.25mm. Styles short c 1mm. Fruit narrowly ellipsoid c 2.5 x 1.5mm.

Bhutan: C—Ha district (Ha [Lit. Ref.117]), Thimphu district (Paro [Lit. Ref. 117], Sharna to Choidi Ponkey, Taba, Tashi Cho Dzong, Thimphu) and Bumthang district (Dhur Valley).

Ecology: Locally abundant in wet meadows and marshes, 2200–3000m. Flowers July–September.

Illustration [51 f-h]

Specimen List [9483]

Oenanthe javanica (Blume) DC.

Oenanthe stolonifera (Roxb.) C.B.Clarke.

A robust stoloniferous herb with erect stems 60–120cm, often rooting at lower nodes. Leaves up to 30 cm long, biternate or bipinnate; segments ovate-acute, 2–5 x 0.75–2.5cm, base cuneate, margin serrate. Umbels large, 5–8cm across, 16–20-rayed; rays 2–3cm long; bracteoles c 4mm. Calyx teeth 0.5–1.5mm. Petals white or greenish yellow, c 1.5mm. Styles as long as calyx teeth. Fruits ellipsoid, c 2.5 x 1.5mm.

Bhutan: S—Deothang district (Narfong [Lit. Ref.117]); C—Tongsa district (Tongsa) and Tashigang district (Tashigang).
Darjeeling: Mahanady (Terai).

Ecology:. Marshy ground, roadside ditches, 150–2600m. Flowers April–October.

Specimen List [9492]

Oenanthe thomsonii C.B.Clarke

A weak diffuse herb with stems 20–80cm. Leaves 3–15(–30)cm long, finely 3–4 x pinnately divaricately divided, ultimate segments linear c 1.5 x 0.25mm. Umbels 3–5.5cm across, 3–9-rayed; peduncle 1–7cm; rays 1–2.5cm; bracteoles 2–3mm; umbellules 6–10mm across; pedicels 2–7mm. Calyx teeth 0.5–1mm. Petals white, 1.25–1.5mm long. Styles 0.75–1mm. Fruit ovoid 2.5–3 x 2mm.

Bhutan: S—Chukka district (Gedu), C—Tongsa district (Chendebi) and Mongar district (Namning, Saling)
Sikkim: widespread.
Darjeeling: widespread

Ecology: A locally common plant of marshy ground in wet broad leaved forest, roadside ditches, etc., 1000–2500m. Flowers April–August.

Specimen List [9553]

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