Siphoneugena occhionii (D. Legrand) Stadnik & Proença 2024

Santos, Matheus F., Amorim, Bruno S., Burton, George P., Faria, Jair E. Q., Fernandes, Thiago, Flickinger, Jonathan A., Gaem, Paulo Henrique, Landrum, Leslie R., Lima, Duane F., Proença, Carolyn E. B., Rosa, Priscila O., Lima-Dos-Santos, Leidiana, Setubal, Robberson B., Stadnik, Aline M. S., Staggemeier, Vanessa G., Vasconcelos, Thais N. C. & Lucas, Eve J., 2024, A taxonomic account of Myrciinae (Myrteae, Myrtaceae): generic and sectional placement of forgotten species and a list of all accepted species, Phytotaxa 674 (2), pp. 129-170 : 133-134

1.8. Siphoneugena occhionii (D. Legrand) Stadnik & Proença , comb. nov. Marlierea occhionii D. Legrand (1962: 37) . Type:— BRAZIL. Rio de Janeiro, Parque Nacional da Serra dos Órgãos, 6 July 1947, Occhioni 1044 (holotype MVM!; isotype RB or RFA [lost?]).

Santos et al. (2020) noted that Marlierea occhionii D.Legrand presents typical features of subtribe Pliniinae , such as the midvein raised on the adaxial surface, hypanthium prolonged beyond the ovary apex and reduced calyx lobes that split irregularly at anthesis. However, the type specimen is in young bud and at that time authors had no access to additional specimens. The species is now known from the type and from three other collections in Atlantic Forest in the state of Rio de Janeiro: L.F. Gonçalves 307 (K, RB, UB) and 311 (RB, RBR, UB, UPCB) from the Serra dos Orgãos, and M.C. Souza 995 (RB, RFA) from the vila de Mambucaba (Paraty). The deciduous hypanthial cup of specimen Gonçalves 311 allows us to unreservedly place this species in Siphoneugena . It is morphologically similar to Siphoneugena densiflora O. Berg (1857: 379) that also occurs in Rio de Janeiro state but at higher altitudes (800–1150 m vs. below 500 m in S. occhioni ).

Siphoneugena occhioni can be distinguished from S. densiflora (in the state of Rio de Janeiro) by: the leaf apex abruptly acuminate or cuspidate with a fine tip (vs. usually attenuate or abruptly acuminate with tip blunt); young branches dark brown, peeling in long and thin strips as they grow in diameter (vs. greyish, peeling in small thin flakes); inflorescence a lax, delicate botryoid, with the terminal flower long-pedicellate, or solitary flowers (vs. congested, umbelliform raceme); pedicels usually 2–3 times as long as the floral buds, rarely twice as long (vs. about the same length as the floral buds or rarely up to twice as long); bracteoles caducous in very young bud, narrowly deltoid and surpassing the ovary (vs. persisting at least to anthesis, deltoid and shorter or equalling the ovary apex); many conspicuous dark colleters in bracteole axils (vs. absent or inconspicuous); buds 4–6 mm long (vs. up to 3.5 mm); petals unguiculate (vs. wide and truncate base); ovules 2 per locule (vs. ovules 4–5(–8) per locule).