Dasistoma macrophyllum (Nutt.) Raf.
Family - Orobanchaceae
Stems - To 2m tall, herbaceous, erect, retrorse pubescent, branching, multiple from base.
Stem 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.
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.
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.
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.
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.
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).