Many species of Orchids have been discovered, and added to the list of the orchids of Brazil and the Amazon region through the research of João Batista Fernandes da Silva and included in the list of new Orchids from Brazil and from Amazon region. The Genus Acacallis Lindley, proposed in 1853, had been reduced in two species by G. Pabst in his work "Orchidaceae Brasilienses". The field research conducted by João Batista Fernandes da Silva has been able to prove the validity of some species of Acacallis that had been put into synonym, and to discover news species of Acacallis such as Acacallis rosariana.

This new species was found in 1989 by the Museo Gueldi researches, U. Maciel and Carlos da Silva Romario in a flooded region in the Forest Reserve of Samuel, Jamari River, close to the city of Porto Velho in the State of Rondônia. In 1998, João Batista Fernanades da Silva found this new species again in large quantities growing in Buriti palms, in a flooded region of the "Parque Estadual de Corumbiara", on the Mequém River, a tributary on the right (north) side of the Guaporé River in the State of Rondônia.
This new species, froms a large homogeneous population, with distinctive caracteristics of short rhizome (when compared with Acacallis cyanea Lindl.), longer and narrower leaves, smaller floral segments than Acacallis cyanea and multi-toothed callus.

  Acacallis rosariana V. P. Castro & J. B. Silva sp.nov. TYPE: BRAZIL: Rondônia: Mun. Porto Velho. 50- 100m de altitude, collected, in 18/01/89, by U. Maciel and Carlos da Silva Rosário, No. 1643. (HOLOTIPO MG No. 133092).

Specii Acacallis Cyanea Lindl. similis, sed folis longioribus et minus latis, pseudobulbis cooptatioribus, floribus ¾ magnitudibus, petalae et sepalae minus magnae, 3/4 latis petalis, labelo ¾ magnitudi, labelli callorum in prior pars cum 3 cornua.

Herb epiphytic. Roots thin, white, glabrous, issuing from the internode of the rhizome. Rhizome evident. Pseudobulbs oboval-elongate, apex acute, initially coveredclouted by the leaf bases that later are shed, 1 apical leaf; 3.6-5.0cm long and 1.2-2.0cm wide. Leaves oblanceolate, 30cm long and 6.0-7.0cm wide. Inflorescence emerging from the axial sheaths of the developing pseudobulb, 25cm long with to 6-10 flowers. Floral bract triangular-elongate, acute, 3-4mm long. Flower very showy, with spreading open segments, sepals and petals, internally white, externally pale blue, lip purple, callus white with purple spots at the base; total lip, 5cm between the sepals. Sepals, dorsal, lanceolate, apex acute, narrowed at the base, concave, 3.5cm long and 2.2cm wide; laterals, oblanceolate, asymmetric, concave, apex acute, 3.5cm long and 2.2cm wide. Petals circular, narrowed at tha base, slightly concave, 2.5cm long and 2.0cm wide. Lip spreading, narrowed base; the frontal part saccate in the intersection with the callus, semicircular 1.6cm long and 2.1cm wide when flattened; callus multi-toothed with 3 acute frontal teeth and 2 small ones (horns shaped teeth) attached at the sides of the callus; 2 triangular auricles, acute, the total length lip 2.5cm. Column erect, slightly arched, auricles ligulate and large, 1.8cm long. Anther subquadratic, biloculate. Pollinia 4. Stigmatic cavity triangular.

  ETMOLOGIE. Related to the Researcher Mr. Carlos Samuel Rosário, from the "Museo Gueldi".
At the first apparance, this seems to be Acacallis Cyanea Lindl, but a closer examination there are a number of differences, that we can point out: Acacallis rosariana has pseudobulbs more clustered than those of Acacallis cyanea, leaves longer and narrower, inflorescence developing from immature pseudobulbs, smaller flowers, with petals noticeably circular and smaller, lip shorter and smaller, callus multi-toothed (Acacallis cyanea callus is uniforme and serrulated) with 3 acute frontal teeth.



Pabst, G.F.J. & Dungs, F. 1975-1977. Orchidaceae Brasiliensis 2 vols. Hildescheim: Kurt Schmersow

Hoehne, F. C., 1953. Flora Brasilica 5 vols. IMPRES, Secr. De Agricultura do Est. de S. Paulo

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Photo: Vitorino Paiva Castro Neto - Illustration: Marcos Antonio Campacci