Eryngium yuccifolium Michx.

Rattlesnake Master

Eryngium yuccifolium plant

Family - Apiaceae

Stems - Glabrous, few-leaved, glaucous, terete, to +/-1.5m tall, from a mass of tuberous roots.

Eryngium yuccifolium stemStem and base of cauline leaf.

Leaves - Mostly basal, with aristate serrations on margins, glabrous, glaucous, to 100cm long, +/-6cm broad, linear, with parallel venation.

Eryngium yuccifolium leafPressed leaf.

Inflorescence - Terminal bracteate cymes. The bracts subtending each cyme division lanceolate and foliate, reduced upwards. Peduncles glabrous and glaucous. Flowers in capitate globose clusters terminating each peduncle. Clusters bracteate, to +/-2cm in diameter. Individual florets sessile, subtended by one chaffy bract. Chaff glabrous, acute, partially enclosing the floret, to 1cm long, glabrous. Receptacle subglobose.

Eryngium yuccifolium inflorescence

Flowers - Florets to +/-6mm long. Petals 5, white, glabrous, irregular, to 3mm long. Styles 2, exserted, greenish-white, glabrous, to 5mm long, with a green nectariferous ring at base. Ovary inferior, covered with small scarious scales, 2-locular, 2-seeded(one seed per locule). Stamens 5, distinct, folded back on themselves at first and then erect and exserted. Filaments glabrous, greenish white, to 3-4mm long. Anthers greenish, to 1.3mm long. Sepals 5, erect, stiff, to +3mm long, +2mm broad, ovate, aristate, green with whitish margins, glabrous but minutely denticulate on midrib abaxially.

Eryngium yuccifolium flowers

Flowering - June - September.

Habitat - Prairies, open woods, glades, also cultivated.

Origin - Native to U.S.

Other info. - The plant, at first glance, appears as an Agave or Yucca. The flowers really give away the fact that it belongs with the carrots. The stems of the plant also have a carrot fragrance when crushed.
This species is widely cultivated.

Photographs taken at Bethel Prairie, Barton County, MO., 7-4-03, and at the Sunklands Conservation Area, Shannon County, MO., 7-26-04.