Heterotheca stenophylla var. stenophylla is the sparsely hairy and often densely glandular variety in the species. It is diploid throughout its range with some tetraploids occurring mostly in the central portion of the range (Semple 2008).
Last revised 30 April 2025 by J.C. Semple
© 2025 J.C. Semple, including all photographs unless otherwise indicated
1-2. Heterotheca stenophylla var. stenophylla. 1. Mid size plant, Kansas. 2. Upper stem and heads, Semple & Brammall 2731, Major Co., Oklahoma.
Nesom (2020) split var. stenophylla into two species, H. stenophylla with large solitary heads (9-17 mm wide when pressed) and H. scabrifolia (A. Nels.) Nesom with heads usually in cymiform to subcymiform clusters (5-8 mm wide when pressed) and more consistently glandular stems and leaves. H. scabrifolia occupies all of the northern 3/4 of the range shown Semple (1996) and restricting his narrowly defined H. stenophylla to just 10 counties around and west and northwest of Austin, TX.