Kentucky Plant Atlas




Taxonomic distinction unclear    No county information
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Asteraceae <Heliantheae> Helianthus <Divaricati> resinosus ("tomentosus")
Helianthus resinosus Small
ALI: no HAB: n/a, n/a, n/a, n/a ABU: n/a, n/a, 0
This taxon has been described and named in various ways; its circumscription remains somewhat uncertain (Sm, F, Cr, FNA 21, W). It is not known in Ky., but plants of tuberosus in the Mississippian Embayment that have more strongly reflexed, longer phyllaries (perhaps with more resin dots), densely velutinous lower leaf surfaces and shorter petioles (perhaps with broader wings) may reflect hybridization with resinosus (FNA 21). H. resinosus is a relatively large-headed (but moderately short-petioled) species. It is a closely related hexaploid of similar habitats to tuberosus further south, locally abundant from Miss to N.Car. It is rare in Va. (F; see also T. Bradley #22890 at GA, det. JC); it has been reported from Tenn. (GSMNP) and it may be expected in w. Ky. However, there is also potential confusion with the medium-headed, shorter-petioled trachelifolius more typical of drier habitats; see notes under that name. H. resinosus is probably closest to tuberosus but may differ as follows (Cr, FNA 21, W): rhizomes lacking tuberous thickenings; stems often reddish or purplish (versus green or sometimes glaucous), petioles mostly 0.5-2 cm (versus 2-8 cm); leaf blades mostly 3.5-9 cm wide (versus 7-15 cm), lower surfaces hirsute to tomentose or velutinous* (versus puberulent or hirsutulous to tomentulose); phyllaries mostly 10-20 x 3-6 mm (versus 8.5-15 x 2-4 mm), usually exceeding disc and reflexed (versus loosely spreading) ; paleae 9-11 mm (versus 8-9 mm); rays 18-30 mm long (versus 25-40 mm); disc corollas 8-8.5 mm long (versus 6-7 mm). [*F stated: "densely soft-pubescent" under tomentosus.]