Silphium terebinthinaceum
Hort. Bot. Vindob. 1: 16, plate 43. 1770.
Common names: Prairie-dock
Revision as of 20:35, 16 December 2019 by FNA>Volume Importer
Plants scapiform, (40–)100–250+ cm; taprooted. Stems terete, glabrous. Leaves: basal persistent, petiolate; cauline alternate, petiolate or sessile; blades cordate, deltate, lanceolate, ovate, or sagittate, 3–40 × 1–40 cm, sometimes (proximal) pinnately lobed, bases attenuate, cordate, hastate, round, or truncate, ultimate margins coarsely toothed or entire, apices acuminate, acute, or obtuse, faces glabrous or scabrous. Phyllaries 23–33 in 2–3 series, outer appressed, apices obtuse to acute, abaxial faces glabrous. Ray florets 17–29; corollas yellow. Disc florets 120–140; corollas yellow. Cypselae 7–13 × 4–10 mm; pappi 0–1 mm.
Distribution
e North America.
Discussion
Varieties 2 (2 in the flora).
Selected References
None.
Lower Taxa
Key
| 1 | Leaves pinnately lobed | Silphium terebinthinaceum var. pinnatifidum |
| 1 | Leaves not lobed | Silphium terebinthinaceum var. terebinthinaceum |