Antennaria plantaginifolia (L.) Hook

Antennaria plantaginifolia plant

Family - Asteraceae

Stems - To +20cm tall, herbaceous, stoloniferous, with fibrous roots, dense lanate, simple, erect.

Leaves - Basal leaves petiolate. Petioles to 3-4cm long. Blade to +4cm long, +2cm broad, tapering at base, entire, broadly elliptic, dense white lanate below, sparse lanate above and greenish, with 3 main veins(visible below). Cauline leaves sessile, linear to linear lanceolate, lanate below, very sparse lanate above, to 2cm long, 5mm broad, entire.

Antennaria plantaginifolia leavesBasal leaves.

Antennaria plantaginifolia basalsRosette in-situ.

Inflorescence - Flower heads in compact clusters terminating stems. Plants dioecious.

Involucre - To 5mm tall(long), 3-5mm in diameter, densely arachnoid pubescent. Phyllaries to 5mm long, 1.2mm broad, green with scarious margins and long scarious apex, glabrous internally, in 1-2 series, imbricate. Staminate involucre slightly more broad and short than pistillate.

Antennaria plantaginifolia involucrePistillate involucre.

Ray flowers - Absent.

Disk flowers - Pistillate flowers - Corolla tube greenish, glabrous, 4.5mm long. Style bifurcate, exserted, purplish at apex. Achenes cylindric, glandular pubescent, 1.6mm long in flower. Pappus a single series of barbellate bristles. Bristles white, to 5-6mm long. Receptacle conic, naked. Staminate flowers, (shown at top of page), - Corolla tube greenish, glabrous, 2.5mm long, expanded at apex for -2mm, 5-lobed. Lobes acute, .6mm long, often recurved. Stamens 5, adnate at base of corolla tube. Anthers exserted, brownish-purple, -2mm long, connate around rudimentary style. The style slightly exserted beyond the anthers. Pappus of barbellate bristles in a single series, to 4mm long. Achenes reduced. Receptacle conic, naked.

Antennaria plantaginifolia pistillatePistillate flowers.

Antennaria plantaginifolia staminate flowersStaminate flowers.

Antennaria plantaginifolia fruitsHeads in fruit.

Flowering - April - June.

Habitat - Acid soils of dry rocky ground, ravines, thickets, roadsides, ridges, prairies, glades.

Origin - Native to U.S.

Other info. - This is a common little plant in Missouri and is easy to ID in the field. The species name means "leaves of Plantain" and indeed the basal leaves do look like those of the genus Plantago. Even though the plants are dioecious, the pistillate plants can still produce viable seed without fertilization from the staminate plants.

Photographs taken in the Piney Creek Wilderness, Barry County, MO., 4-5-04.


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