Gamochaeta Wedd.

Echeverría, María L., Alonso, Sara I. & Comparatore, Viviana M., 2017, Survey of the vascular plants of Sierra Chica, the untouched area of the Paititi Natural Reserve (southeastern Tandilia mountain range, Buenos Aires province, Argentina), Check List 13 (6), pp. 1003-1036 : 1026

Genus Gamochaeta Wedd.

Gamochaeta pensylvanica (Willd.) Cabrera Figure 34 Gamochaeta pensylvanica (Willd.) Cabrera (1961) : 376 — Cabrera

(1963): 175; Hurrell (2013): 157; Freire and Ihlarlegui (2014): 477;

Flora Argentina (2017); Tropicos (2017).

Gamochaeta platensis (Cabrera) Cabrera (1961) : 376 — Cabrera (1963):

168; Hurrell (2013): 152.

Gnaphalium platense Cabrera (1941) : 167.

Gnaphalium pensylvanicum Willdenow (1809) : 829.

Hemicryptophyte, native with distribution in the Southern Cone Region of South America; previously recorded from Buenos Aires province but not from mountainous areas. Vulnerable, reasons unknown ( Delucchi 2006).

Characteristics. Perennial herb, to 60 cm tall, with simple ascending branches, densely covered with leaves and lanate and glandular hairs. Leaves with spatulate shape, mucronate or obtuse apex, entire margin and attenuate to decurrent base. Leaf surface concolor or weakly bicolor with lanate and glandular hairs, denser on the abaxial surface. Inflorescences: capitulums with numerous filiform outer florets and only 3 or 4 tubular disc florets, arrange in glomerules, placed over pseudospiciform arrays interrupted by leaves. Phyllaries with lanate hairs.

Comments. This is a frequent species in the study area. It grows in intermediate and full sunlight conditions and on shallow soils and cracks on the slopes and summit. It differs from other Gamochaeta species that grow in Buenos Aires province by the leaf hair type: G. pensylvanica has lanate and glandular hairs. Cabrera (1963) and Hurrell (2013), who only noted the presence of glandular hairs in G. platensis , considered G. pensylvanica and G. platensis to be different species.. However, Freire and Iharlegui (2014) considered that these taxa to be synonyms.