Silphium laciniatum

SIMILAR SPECIES: Flowering plants are very distinctive and conspicuous. Vegetative specimens can be confused with non-flowering plants of prairie-dock (Silphium terebinthinaceum), especially with cut-leaved variants of the latter. In other states, hybrids between these two species have been reported.

TOTAL RANGE: OH, MN, and ND, s. to OK and TX.

STATE RANGE: A single population is extant in Lawrence County. Reported in 1966 from a site in Erie County that subsequently has been disturbed, the species no longer can be found there. There are pre-1960 records from Franklin and Summit counties.

STATE STATUS: 1980 to present: Endangered.

HABITAT: In full sun on well-drained, clay or calcareous substrates: pastures, dry prairies, railroad embankments. The Ohio population occurs on a steep, grazed slope subject to landslips.

HAZARDS: Overgrowth by woody species; over-grazing.

RECOVERY POTENTIAL: Probably very good; the species grows well in cultivation and is tolerant of moderate disturbance; the deep taproot resists seasons of drought.

INVENTORY GUIDELINES: Identification should be based upon flowering material only; many other composites are popularly called “compass-plant,” such as wild lettuce (Lactuca sp.).

COMMENTS: This species when in bloom is exceedingly conspicuous. Its distribution in Ohio probably is accurately known. Fisher (1966) suggests, though, that the prairie-dock (Silphium terebinthinaceum) in Marion County shows evidence of introgression from S. laciniatum. Though no compass-plant has ever been reported from Marion County, it may have been found there at one time. Further research may help elucidate the situation.

Some authors split this species into two varieties, though most taxonomists do not accept this concept. Under such a treatment, Ohio plants are the typical variety.

SELECTED REFERENCES:

Auffenorde, T.M. and W.A. Wistendahl. 1983. Demography and persistence of Silphium laciniatum at the O.E. Anderson Compass Plant Prairie. p. 30-32. In: Brewer, R. (ed.) Proceedings of the eighth North American Prairie Conference. Western Michigan Univ., Kalamazoo, MI. 176 p.

Cronquist, A. 1980. Vascular flora of the southeastern United States. Vol. I. Asteraceae. Univ. of North Carolina Press, Chapel Hill, NC. xv + 261p.

Cusick, A.W. 1981. Compass-plant (Silphium lsciniatum) in Ohio: its historic and present-day distribution. (abs.) p. 262. In: Stuckey, R.L. and K.J. Reese., eds. The Prairie Peninsula – in the “shadow” of Transeau. Proc. Sixth N.A. Prairie Conference. Ohio Biol. Surv. Biol. Notes No. 15. 278 p.

Fisher, T.R. 1966. The genus Silphium in Ohio. Ohio J. Sci. 66: 259-263.

Fisher, T.R. 1988. The Dicotyledoneae of Ohio. Part 3. Asteraceae. Ohio State Univ. Press, Columbus. 280 pp.

Division of Natural Areas and Preserves

Ohio Department of Natural Resources

Created: 2/1984 Allison W. Cusick

Database Code: SPNX.E13