Houstonia rupestris Rafinesque. Cliff Diamond-flower. Phen: May-Oct. Hab: Limestone river bluffs and cliffs. Dist: Largely restricted to limestone cliff-tops along the Kentucky River Palisades, the Cumberland River in KY and TN, and perhaps the Sequatchie Valley in TN.
Origin/Endemic status: Endemic
Syn: < Hedyotis nigricans – C, Rogers (1987); < Hedyotis nigricans var. nigricans – K1, Tn, Terrell (1986), Terrell (1991), Turner (1995b); < Houstonia angustifolia – S; < Houstonia nigricans – F, G; < Stenaria nigricans var. nigricans – K3, K4, Terrell (2001)
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