Distinguishing Silphium in Illinois by their leaves

S. terebinthinaceum: Large upright arrow-shaped leaves at base of plant
https://www.inaturalist.org/observations/31934856

S. intergrifolium: leaves opposite going up stem but not joined together
https://www.inaturalist.org/observations/31935369

S. perfoliatum: leaves opposite going up stem and joined together forming a cup
https://www.inaturalist.org/observations/29797854

S. lacinatum: leaves highly lobed and pointed
https://www.inaturalist.org/observations/29409542

Posted on Σεπτέμβριος 09, 2019 0328 ΜΜ by k2018lena