Plazia conferta Ruiz & Pav., Syst. Veg. Fl. Peruv. Chil. 187. 1798.

Dillon, Michael O. & Luebert, Federico, 2014, Synopsis of Plazia Ruiz & Pav. (Onoserideae, Asteraceae), including a new species from northern Peru, PhytoKeys 34, pp. 1-13 : 3-4

2. Plazia conferta Ruiz & Pav., Syst. Veg. Fl. Peruv. Chil. 187. 1798.

Type.

PERU. Junín: Acobamba [near Tarma], H. Ruiz L ó pez & J.A. Pav ó n s.n. (holotype: MA, n.v.).

Description.

Shrubs, branched, branches glabrous. Leaves oblanceolate, 22-42 mm long, 5-6 mm wide, glabrous, sessile, acute-mucronate, margin entire. Capitula with involucres 18-22 mm high, 12-16 mm wide; phyllaries 6-7-seriate, glabrous, lanceolate, the inner 22-25 mm long, 3-3.5 mm wide, acute, the outer gradually smaller; ray florets 18-20, the corollas 26-28 mm long, the tube 10-11 mm long, glabrous, the outer lip 14-15 mm long, 5-6 mm wide, 4-nerved, tridentate, the inner lip bipartite; disc florets 40-42, the corollas 15-18 mm long, the tube glabrous, the lobes 9-10 mm long, 1-1.2 mm wide, coiled; anthers 6-7 mm long. Achenes [ray] 4-5 mm long, 1.5-1.6 mm wide, glabrous; pappus c. 12 mm long; [disc] 4.5-5 mm long, 1-1.2 mm wide; pappus c. 14 mm long.

Distribution.

Endemic to an inter-Andean valley in central Peru from near Tarma; c. 3000 m. Given that this species appears confined to a single locality and of a few individuals, it would be considered "critically endangered" ( IUCN 2001).

Discussion.

Plazia conferta is a rare species, and type material has not been located. No new material had been collected since Ruiz López and Pavón’s original gathering until a second collection was made by Felix Woytkowski at the type locality nearly 180 years after its original description. Cabrera (1960) was unsuccessful in locating Ruiz López and Pavón’s type material in the major European herbaria, including Madrid. We made inquiries to the Real Jardín Botánico in Madrid, but no collection of Plazia has surfaced as yet. Ferreyra (1980) cited duplicates of Woytkowski 52 as occurring at MO and F, but after exhaustive searching, no duplicate collections were located, and subsequently the duplicates were not cited in Ferreyra’s Flora of Peru treatment (1995). Further, during this study, we were unsuccessful in our efforts to examine the Woytkowski collection at USM, and the description provided by Ferreyra (1995) was used to quantify the differences between that species and the new one described here.

There is an error in the citation of the generic description in Florae Peruvianae Chilensis Prodromus (1794), where page “104” is cited in Systema Vegetabilium Florae Peruvianae et Chilensis (1798) incorrectly, and the generic description is actually on page 92.