Przemysław Baranow

New species of Sobralia section Abbreviatae Brieger (Orchidaceae) from Colombia. A morphological and molecular evidence

Sobralia vallecaucana, section Abbreviatae from Valle del Cauca, Colombia, is described and illustrated on the basis of morphological and molecular study. The analyses of the ITS and matK reveal close relationship between the new species and Sobralia klotzscheana. However, S. vallecaucana can be easily distinguished by its large leaves compared to its very short stem, leaves and leaves’ sheaths strongly hispid underside and lip with two basal ridges and without thickening along its central nerves.

Phylogenetic Placement and Taxonomy of the Genus Hederorkis (Orchidaceae)

Three plastid regions, matK, rpl32-trnL and rpl16 intron and the ITS1-5.8S-ITS2 nuclear ribosomal DNA were used to demonstrate a phylogenetic placement of the genus Hederorkis (Orchidaceae) for the first time. The taxonomic position of this genus has been unclear thus far. The phylogenetic and morphological relations of Hederorkis to the most closely related genera Sirhookera, Adrorhizon, Bromheadia and Polystachya are also discussed. A hypothesis concerning an origin and evolution of Hederorkis is proposed. Hederorkis is an epiphytic two-leaved orchid genus with lateral inflorescence, non-resupinate flowers, elongate gynostemium and rudimentary column foot. It is native to the Indian Ocean Islands. Two species of Hederorkis are recognized worldwide, H. scandens endemic to Mauritius and Réunion and H. seychellensis endemic to Seychelles. For each of the species treated a full synonymy, detailed description and illustration are included. The distribution map and dichotomous keys to the species have also been provided.

Sobralia pakaraimense (Orchidaceae), a New Species from Guyana

Sobralia (Orchidaceae) is a genus of about 150 species distributed in Mesoamerica and tropical and subtropical regions of South America. Its species are most often tall plants with single, showy but fugacious flowers. As the result of a morphological study based on herbarium material examined by the authors, Sobralia pakaraimense Baranow & Szlach. from Guyana is described and illustrated as a new species. A key for determination of all Sobralia species reported till now from Guyana is provided.

Four New Species ofCleistes(Orchidaceae, Vanilloideae) from Colombia

Four new Colombian species of Cleistes (Orchidaceae, Vanilloideae) are described and illustrated: C. uribei Szlach. & Baranow, C. risoraldensis Szlach. & Baranow, C. munchiquensis Szlach. & Baranow and C. idroboi Szlach. & Baranow. Notes concerning their morphological distinctions, habitat, and distribution are provided. A key for determination of the Colombian species of Cleistes is included.

Notes on the Genus Sertifera (Orchidaceae, Epidendroideae)

Abstract Sertifera is a small orchid genus consisting of nine species distributed in Andean regions of Ecuador, Colombia, and Venezuela. Representatives of the genus are erect, slender plants growing terrestrially, rarely as epiphytes or lithophytes. In habit, the plants resemble Sobralia and Elleanthus species. However, flowers, especially the lip, of Sertifera are unique and make the genus different from all others. No previous comprehensive treatment of the genus exists, and the only key for determining Sertifera species was published by Garay in 1978, involving Ecuadorean taxa exclusively. Here we present the first key including all species of the genus, along with available details concerning morphology, distribution, and ecology. Based on differences in lip morphology and flower arrangement, the genus is divided into three sections; Sertifera, Aurantiacae, and Racemosae. Sertifera gracilis, discovered by Reichenbach, is validated. Sertifera risaraldana is described as a new species.

A phylogenetic and morphological study of Polystachya sect. Superpositae (Orchidaceae) with description of a new species from Cameroon

Polystachya section Superpositae is a group of montane and submontane African epiphytes with thirteen species (including the newly described in this paper). During a scientific expedition to Bamenda Highland, Cameroon a new species, Polystachya bamendae, was found and it is described here. The new entity was compared with 398 herbarium specimens representing the section, including the type collections. The molecular analyses of the ITS and matK strongly support the results of morphological studies and reveal close relationship between the new species and the species of the section Superpositae. Two hypotheses supporting function of the matK gene in the examined species are presented. The phylogenetic and morphological relation of Polystachya bamendae to P. lindblomii and P. superposita is discussed. The distribution range of the section is analyzed and a discussion about the distribution of the species is presented. A distribution map of the section and dichotomous key to the species of Superpositae are provided. The occurrence of the species of the section in two Biodiversity Hotspots (Guinea Forests of West Africa and Eastern Afromontane) is discussed.

New species of the genus Epistephium (Orchidaceae, Vanilloideae)

The morphological study of the herbarium material representing Epistephium (Orchidaceae, Vanilloideae) led to the discovery of two groups of specimens that significantly differ from all known species of the genus. The results of literature data study and of comparative analysis of those and other specimens suggest that these collections represent new taxa that we describe as E. garayi and E.kubiyuense. The distinguishing features of the species are indicated. As both new species are reported from Colombia (E. garayi, also from Guyana), the key for the determination of all Colombian representatives of the genus is included. Information on the ecology and distribution of newly described taxa is presented.

Two new species of Polystachya Hook. (Orchidaceae) from Africa

Two new species of Polystachya Hook. are described and illustrated: Polystachya rydingii Baranow & Mytnik occurring from the Democratic Republic of Congo and P. sosefii Baranow & Mytnik from Cameroon. The species belong to the section Polystachya Kraenzl., which is the only pantropical section in the genus. Maps of the distribution for the new species and their closest relatives and a brief discussion with notes on their habitat, ecology, and altitude are provided.

Materials Towards Taxonomic Revision of the Genus Palmorchis (Orchidaceae)

Abstract The orchid genus Palmorchis consists of 34 species distributed in Central and South America. It is one of the most poorly known genera of the Orchidaceae. With vegetative organs resembling the seedlings of palm trees and having inconspicuous flowers, its representatives have rarely drawn the attention of botanists, resulting in scarce availability of materials in herbaria for proper examination. This paper focusses on the diversity of Palmorchis species, their morphology, ecology, and distribution compiled from herbarium material, fieldwork, and literature data. The genus is divided into six informal groups. This review has resulted in the discovery of five new species (P. dressleriana, P. antioquiensis, P. schneideri, P. rubioi, P. chocoensis) that are described herein. A dichotomous key for the determination of all the species of the genus is provided. Line drawings of flower details and plant habit for all species are included.

Brasolia, a new genus highlighted from Sobralia (Orchidaceae)

A phylogenetic study of Sobralia (Orchidaceae) confirmed the polyphyletic character of the genus. Sobralia also appears to be highly heteromorphic in the morphology, especially considering the position and architecture of inflorescence, lip form and kind of its outgrowths, length and form of stelidia of column. The infrageneric relationship of Sobralia species was revealed by analyses of three DNA markers (nuclear ITS, xdh and plastid matK). The nominal section of the genus appears to be more related with Elleanthus and other genera of Sobralieae than with the remaining species of Sobralia. Sobralia section Sobralia differs from other representatives of the genus by the position and architecture of inflorescence, smaller floral bracts and the morphology of the flowers. We propose a generic rank to the group despite its paraphyletic nature. Nomenclatural consequences of this proposal are briefly discussed. Appropriate transfers to the newly erected genus Brasolia are proposed. A new species, Brasolia floribunda, previously detected by Reichenbach, but never formally described, is validated. Lectotypes for five species and a neotype for the other one are proposed.