Andrachne phyllanthoides (Nutt.) M. Arg. - Buck Brush

Andrachne phyllanthoides plant

Family - Euphorbiaceae

Stems - Woody, to +/-1.5m tall, erect, branching. Twigs ferruginous, with some long strigose hairs or glabrate, often with some vertical grooves, ribs, or angles.

Andrachne phyllanthoides stem

Leaves - Alternate, short-petiolate to sub-sessile. Petioles to 2mm long, glabrous or with some hairs adaxially. Blades orbicular (more or less), entire, glabrous, deep green above, lighter below, +/-2.5cm long and broad.

Andrachne phyllanthoides leaves

Inflorescence - Axillary fascicles of few to many flowers. Fascicles subtended by ferruginous bracts. Bracts to 2mm long, .6mm broad (at the base), attenuate, ciliate-margined, with some hairs on both surfaces. Pedicels of flowers to 1.5cm long in pistillate flowers and shorter in staminate flowers, glabrous, thin.

Andrachne phyllanthoides inflorescence

Flowers - Staminate flowers with 4-5 petals and 4-5 sepals being similar, green, to 2mm long, 1.5mm broad, ovate to obovate, rounded at the apex. Sepals with some cilia on the margins. Petals and sepals mostly glabrous or with a few hairs externally. Stamens 5, erect, with green expanded nectaries at the base. The nectaries flattened, +/-1mm long. Filaments greenish, 1.5-2mm long, glabrous. Anthers yellow to tan, .2-.3mm long. Styles 3, glabrous, greenish, 1.1-1.2mm long. Pistillate flowers with 5 sepals. Sepals accrescent, to 5mm long, 4mm broad, broadly obovate, glabrous, rounded at the apex. Capsule with the styles persistent and short. Styles bifurcate at the apex and reflexed, 1mm long, becoming purple, the stigmas recurved. Capsule to +/-7mm in diameter, 6-seeded, 6-valved, green, glabrous.

Andrachne phyllanthoides flowerStaminate flower close-up, with ant.

Andrachne phyllanthoides capsuleDeveloping capsule.

Flowering - May - October.

Habitat - Gravel bars, limestone bluffs, knobs, glades.

Origin - Native to U.S.

Other info. - This interesting species can be found in just a handful of southern Ozark counties. It is the only woody member of its family to be found in Missouri and is easy to identify because of its rounded leaves, small flowers, and habitat.
Steyermark wrote that perhaps this species was a relic from the time before the last Tertiary uplift which has survived because of adaptations to cold, drought, and exposure. The rest of the woody euphorbs are all tropical.

Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 7-6-03.


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