in F. Cuvier, Dict. Sci. Nat. ed.2, 25: 91. 1822
Mostly subtropical, tropical, and warm-temperate New World.
Species ca. 18 (6 in the flora).
G. L. Nesom (1990) argued for segregating some species from Conyza as members of Laënnecia. Although there are exceptions to each of the trends noted by Nesom, the rationale he presented is compelling. R. D. Noyes and L. H. Rieseberg (1999) demonstrated molecular differences that are consistent with treating laënnecias and conyzas in separate genera; at the same time, they showed Conyza to be “nested” within Erigeron.
|1||Leaf blades densely to loosely tomentose (at least abaxially, sometimes glandular beneath the tomentum); pappi of 30–40+ bristles in 2 series||> 2|
|1||Leaf blades usually hirtellous to villous and usually glandular, sometimes glabrate (usually sparsely and finely tomentose and with coarse, erect, multicellular hairs and stipitate- or sessile-glandular in L. schiedeana); pappi of 9–30 bristles in 1 series||> 3|
|2||Pistillate corollas: laminae 0.5–1 mm; cypselae pale tan to brownish, 2–3 mm||Laënnecia eriophylla|
|2||Pistillate corollas: laminae 0; cypselae purplish, 1.3–1.5 mm||Laënnecia filaginoides|
|3||Leaf blades mostly 1–2-pinnately lobed (lobes ovate to ± linear); pappi 2–3 mm||> 4|
|3||Leaf blades coarsely toothed or entire; pappi 3.5–4 mm||> 5|
|4||Bases of leaves obscurely, if at all, clasping; heads in racemiform or paniculiformarrays||Laënnecia sophiifolia|
|4||Bases of all or at least distal leaves clasping; heads in ± corymbiform arrays||Laënnecia turnerorum|
|5||Leaf blades entire or distally toothed, faces usually sparsely and finely tomentose and with coarse, erect, multicellular hairs and stipitate- or sessile-glandular;pistillate corolla laminae 0.5–1+ mm||Laënnecia schiedeana|
|5||Leaf blades coarsely toothed from near their bases or entire, faces usually both hirtellous tovillous and ± glandular-viscid, not tomentose; pistillate corollalaminae 0||Laënnecia coulteri|
|Author||John L. Strother +|
|Etymology||For René-Théophile-Hyacinthe Laënnec, 1781–1826, French physician, inventor of the stethoscope +|
|Illustrator||Yevonn Wilson-Ramsey +|
|Taxon name||Laënnecia +|
|Taxon parent||Asteraceae tribe Astereae +|
|Taxon rank||genus +|
|Volume||Volume 20 +|