Euplassa rufa (Loes.) Sleumer

  • Authority

    Prance, Ghillean T., et al. 2007. Proteaceae. Fl. Neotrop. Monogr. 100: 1-218. (Published by NYBG Press)

  • Family

    Proteaceae

  • Scientific Name

    Euplassa rufa (Loes.) Sleumer

  • Type

    Type. Brazil. Minas Gerais: prope São João del Rei, 1888 (fl), Glaziou 17199 (holotype, B, photo F, GH, MO; isotypes, C, E, G, K, P n.v., NY, US).

  • Synonyms

    Adenostephanus rufa Loes.

  • Description

    Species Description - Tree. Young stems dark reddish-brown, the indumentum short, densely ferruginous- or rufous-crispate, lost with maturity, strongly striate; older branches grayish to black, glabrescent, intermittently striated, generally small fissured. Lenticels absent to moderately numerous, especially on young branches, minute, < 0.5 mm long, circular to narrowly elliptic, slightly prominent, beige to reddish, producing minute fissures. Petiole 3.2-7.2 cm long, terete, 2.25-3 mm diam, at the base, ferruginous to rufous-crispate. Leaf rhachis 4.2-7.3 cm long, the terminal appendix 2-4 mm long, ca. 1.5 mm broad, frequently absent; leaflets subsessile to short-petiolate, the peti-olules 1-5 mm long, sometimes absent, 2.5-3 mm diam, at the base. Leaflets 2-3 pairs, opposite to weakly subopposite, commonly overlapping, drying olive green to dark brown above, bright ferruginous beneath; subcoriaceous, matte, glabrous to glabrescent above with crispate pubescence at base of lamina, very densely ferruginous-crispate beneath, the indumentum obscuring lamina and tertiary venation, symmetrical to asymmetrical, suborbicular, obovate, oblong to broadly elliptic; basal pair similar to other leaflets but generally more suborbicular, 4.4-9.2 cm × 3.9-5.8 cm; other leaflets 7-9.6 cm × 4.75.7 cm; base equal to weakly oblique, briefly narrowing; apex rounded or obtuse, rarely truncate (although common in basal leaflets), frequently retuse, sometimes minutely mucronulate due to slight extension of the midvein; margin essentially entire, but frequently unevenly and remotely crenate, sometimes undulate; venation cladodromous to less frequently brochidodromous, with 4-6 lateral veins, the midvein prominent, generally reaching the apex, sometimes forking, secondaries not prominent but well marked, higher order venation obscure on both sides of lamina. Inflorescence moderately congested, unbranched, 1.5-2.lcm diam., axillary; peduncle 2.3-3.2 cm long, 1.5-2 mm diam, immediately below inflorescence; floral rhachis 5.2-10.2 cm long, ferruginous- to rufous-crispate; bracteoles strongly heteromorphic, the basal ones 3-8 mm long and 2-6 mm broad, leaf-like, frequently absent, the superior ones linear but with some expansion of distal end, ca. 3 mm, all ferruginous-crispate, curved strongly upwards; flower-pair peduncle 1-3 mm long, 0.8 mm diam., ferruginous- to rufous-crispate; pedicels absent. Buds 2-2.3 mm broad at apex, 1-1.25 mm broad at midlength, essentially erect, ferruginous- to rufous-crispate. Flowers 6-9 mm long, one perianth segment remaining erect at anthesis; tepals ca. 0.5 mm across at midlength, not keeled. Anthers subsessile, ca. 1.5 mm long. Hypogynous nectaries distinct, the two abaxial nectaries closely juxtaposed, trigonous, positioned farther up than the adaxial nectaries, the latter rounded, a large abaxial gap present. Ovary 1-2.5 mm long, pyriform, glabrous. Fruit unknown. Diagnostic characters. Euplassa rufa is easily identified by its characteristic leaflets with entire margins and a bright ferruginous-crispate indumentum beneath that obscures the lamina. The flowers are sessile and subtended by a common peduncle. The ovary is glabrous. Field characters. Unknown.

  • Discussion

    Euplassa rufa is one of the most recognizable species of the genus Euplassa due to its characteristic crispate indumentum, which covers the lower leaf surface so densely that it completely obscures the lamina. The only other species with this dense indumentum is E. cantareirae. The indumentum in E. cantareirae, although strongly ferruginous in color, is not crispate but rather made up of more or less straight hairs in a very short, dense, tomentose to velutinous indumentum. Euplassa cantareirae also differs from E. rufa by possessing remotely serrate leaflet margins instead of entire margins, pedicellate rather than sessile flowers, and a pubescent rather than glabrous ovary.

    Euplassa rufa also shares similarities with E. semicostata, such as leaflet shape, entirely fused pedicels, and distinct hypogynous nectaries. The midvein of this species may, on occasion, not reach the apex, as is commonly the case in E. semicostata. They are easily separated, however, on the basis of ovary pubescence (glabrous in E. rufa and rufous-hirsute, or rufous-puberulent, in E. semicostata) and leaf indumentum (very dense and crispate in E. rufa, and sparsely pubescent and not crispate in E. semicostata).

    The exact distribution of this species is unclear due to inconsistent labelling in the Glaziou collections.

    Glaziou 17199 is the type specimen for E. rufa, duplicates of which are deposited in G, K, NY, and B. In all specimens except the last, the collection locality is Rio de Janeiro. The specimen from B is annotated as having been collected in Minas Gerais, near Sao Joao del Rei. It is possible that the specimen was bought or given as a gift and mislabeled, or that Glaziou used his frequently generic locality of Rio de Janeiro. The areas of Alto de Macahé (Rio de Janeiro) and São João del Rei should be visited to confirm this distribution.

    Phenology. Flowering in Dec; fruiting unknown.

  • Common Names

    Tambu-do-cerrado

  • Distribution

    Euplassa rufa is known from Minas Gerais in the southern extreme of Serra de Espinhaço, from near Ouro Preto and Sao Joao del Rei, and from the Alto de Macahé in the state of Rio de Janeiro.

    Rio de Janeiro Brazil South America| Minas Gerais Brazil South America|