Dasistoma macrophylla

Mullein Foxglove

Dasistoma macrophylla plant

Family - Orobanchaceae

Stems - To 2m tall, herbaceous, erect, retrorse pubescent, branching, multiple from base.

Dasistoma macrophylla stemStem and node.

Leaves - Opposite. Lowest leaves large, pinnatifid, pubescent, to 30cm long, short-petiolate. Lobes again divided. Ultimate divisions coarse serrate. Upper leaves lanceolate, lobed to crenate or entire, pubescent.

Dasistoma macrophylla leaf

Dasistoma macrophylla leaf

Inflorescence - Terminal spikiform racemes on the main stems and branches. Flowers subtended by foliaceous bracts. Pedicels to +1.5mm long. Inflorescence appearing as just paired axillary flowers because of the foliaceous bracts.

Dasistoma macrophylla inflorescence

Flowers - Corolla zygomorphic, yellow, 5-lobed. Corolla tube to 8mm long, white at very base, yellow above, bearded internally at least near apex. Lobes spreading or reflexed, to 6mm long, rounded, unequal. Stamens 4, didynamous, included to slightly exserted, adnate about 1/2 way up corolla tube. Filaments 2mm long, pubescent. Anthers brown, 2.7mm long, 1mm broad. Style 3mm long. Ovary superior, glabrous, yellow-green, surrounded at base by green ringlike nectary, 2-locular. Placentation axile. Ovules many. Calyx tube 4mm long, retrorse pubescent, purplish-green, 5-lobed. Lobes unequal, ovate, to 6mm long, 4mm broad, pubescent.

Dasistoma macrophylla flowerCorolla close-up.

Dasistoma macrophylla calyxCalyx.

Fruits - Globose capsules, 6-11 mm diameter, slightly flattened, glabrous. Dehiscent longitudinally from tip. Empty capsules often persist on dried stems well into following season.

Dasistoma macrophylla fruitsYoung fruits.

Flowering - June - September.

Habitat - Rich low woods, ravines, valleys, rocky slopes, thickets, bluffs.

Origin - Native to U.S.

Other info. - After spending some time in the field, a person gets a feel for how the flowers of particular plant families look. This plant has classic flowers of the Scrophulariaceae, the family to which this species once belonged. The flowers are tubular, zygomorphic, and 5-lobed. The plant is easy to recognize in the field because of the bright yellow flowers and the large pinnatifid opposite leaves. This species is actually partially parasitic on the roots of larger woody and herbaceous plants.
A synonym previously in use was Seymeria macrophylla Nutt.

Photographs taken at the Springfield Nature Center, Springfield, MO., 7-5-03, and at Pultite Spring, Shannon County, MO., 7-23-04 (DETenaglia); also at Onondaga Cave State Park, Crawford County, MO, 7-31-2014, and Shaw Nature Reserve, Franklin County, MO, 8-20-2017 (SRTurner).


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