Tuesday, April 30, 2024

[Botany • 2024] Gynoxys revolutifolia (Asteraceae: Senecioneae) • A New Species from southern Ecuador

Gynoxys revolutifolia R. Arias, Espinosa-Ortega & Revilla, 

in Arias, Espinosa-Ortega, Revilla, Ansaloni et Tomasello, 2024.
Gynoxys is a very diverse genus of Asteraceae with an Andean distribution from Venezuela to northern Argentina. It comprises about 130 species, 34 of which are recorded in Ecuador. In the present study, we describe Gynoxys revolutifolia, a new species occurring in Ecuador between Loja and Zamora-Chinchipe provinces. The new species is a shrub or treelet characterized by coriaceous leaves with a strongly revolute margin. After an accurate revision of the main Ecuadorian herbaria and field surveys, we provide a comprehensive comparison of G. revolutifolia with the species it was previously misidentified as. We also provide information concerning the chemical composition, distribution range and conservation status of the new species.

Keywords: Andes, Compositae, Loja, Taxonomy, Zamora-Chinchipe

Lankester Composite Dissection Plate of Gynoxys revolutifolia R. Arias, Espinosa-Ortega & Revilla
A. Flowering branch. B. Leaf: abaxial surface (left), adaxial surface (right). C. Synflorescence. D. Capitulum, front view. E. Capitulum, cross-section. F. Calycle. G. Bracteoles: abaxial surface (left), adaxial surface (right). H. Outer phyllaries: abaxial surface (left), adaxial surface (right). I. Inner phyllaries: abaxial surface (left), adaxial surface (right). J. Ray floret (pappus removed). K. Ray floret style. L. Disc floret (pappus removed). M. Disc floret style. N. Anther. O. Achene (immature). P. Pappus bristles.
Photos and preparation by N. Espinosa-Ortega based on the isotype (QCA249764).

 Gynoxys revolutifolia.
A. Habit, shrub in shrubby páramo, Cerro Toledo-Loja/Zamora Chinchipe border. (R. Ansaloni & N. Espinosa-Ortega 310).
B. Habit, treelet in elfin forest, Yangana-Cerro Toledo road, Loja (R. Ansaloni & N. Espinosa-Ortega 311).
Photos by N. Espinosa-Ortega

Gynoxys revolutifolia R. Arias, Espinosa-Ortega & Revilla, sp. nov. 

Diagnosis:—The new species differs from all other congeners by having coriaceous leaves with strongly revolute margins (giving it a concave shape) and conspicuous primary and secondary veins (8–12 pairs) on both leaf surfaces, simple and T-shaped trichomes covering the abaxial side of the leaves, involucre with 8 phyllaries with ferruginous unicellular trichomes, 4–5 ray florets with limbs 10–11 mm long and 8–9(–12) disc florets. 

Etymology:—The specific epithet of the new species refers to the strong revolute leaf margins.

Ruth Arias, Nelson Espinosa-Ortega, Italo Revilla, Raffaella Ansaloni and Salvatore Tomasello. 2024. Gynoxys revolutifolia (Senecioneae, Asteraceae): A New Species from southern Ecuador.  Phytotaxa. 644(3); 211-219. DOI: 10.11646/phytotaxa.644.3.4