Rubachia involucrata O. Berg (1857: 29)

Santos, Matheus F., Stadnik, Aline, Proença, Carolyn E. B. & Sobral, Marcos, 2020, The near demise of Marlierea: moving last species to correct genera and notes on three incertae saedis taxa (Myrtaceae, Myrteae, Myrciinae), Phytotaxa 447 (3), pp. 195-202 : 199

3. Rubachia involucrata O. Berg (1857: 29) . Marlierea involucrata (O.Berg) Niedenzu (1893: 77) .

Type:— BRAZIL. Rio de Janeiro: without locality, s.d. (fl), Sellow s.n. (syntype: B [destroyed]).

The nomenclature and taxonomy of Rubachia involucrata presents a similar problem to that of Marlierea capitata . Berg (1857 –1859) described Rubachia involucrata based on the collection Sellow s.n. at B (as “in hb. Berol”). The Sellow’s specimens were housed primarily at B although many duplicates were sent to other European herbaria (see Stafleu & Cowan 1985). The material at B was destroyed, but no duplicates with Berg’s handwriting were found at B and in other herbaria. Barroso & Peixoto (1992) suggested that one specimen from Rio de Janeiro (i.e. Farney 2308 at RB) was a representative of M. involucrata . However, it lacks some of the features described by Berg (1857 –1859), specially the thin, numerous veins, the four bracts around the flower bud and the reduced calyx lobes.

Rubachia O. Berg (1855: 27) was latter synonymized under Marlierea by Bentham & Hooker (1865) and considered so by Kiaerskou (1893), Niedenzu (1893), and Legrand (1962). The circumscription of Rubachia is a mixture of Marlierea and Plinia morphologies, but the genus is currently a synonym of Plinia ( Santos & Lucas 2019) . Berg (1855) described R. involucrata with features more related to Pliniinae than to Myrciinae : midvein raised on the adaxial surface of the leaves and four large (and probably persistent) bracteoles covering the floral bud.

However, once again the missing type collection and lack of any unquestionable collections prevent the recognition of the generic affinity of R. involucrata . This species is therefore maintained as incertae saedis.