Psychotria augustaflussiana is described from remote environments in Papua New Guinea's upper Sepik drainage. Taxonomic and distributional notes are provided for Airosperma grandifolia, a frequent associate of the new species but otherwise rarely represented in herbarium collections.

Two new species of Piper are described and illustrated. Piper sotobosquense and P. calvarii, currently considered endemic to Venezuela, are found only on the slopes and montane forests of Guaramacal National Park, Portuguesa and Trujillo states, Venezuela. Taxonomic relationships also are discussed and comments on distribution and ecology are presented.

A new combination in Heliotropium (Heliotropiaceae) from South America is proposed in this paper: Heliotropium lilloi.

The new name Alchemilla purohitii Lakshmin., Bandyop. & Chand. Gupta (Rosaceae) is proposed to replace the later homonym Alchemilla sojakii K.M. Purohit & Panigrahi.

Thirty-five species of the genus Stelis Sw. (Orchidaceae) from Colombia that have not had a complete illustration published are presented in the fifth of a series. Three are described as new.

Two new species of Crocodeilanthe, C. dewildei and C. steinbachii, three new species of Masdevallia, M. calochrysos, M. driesseniana and M. rostriflora, and one new species of Pleurothallis, P. amentacea, are described and illustrated.

Four new combinations in Crocodeilanthe (Pleurothallidinae, Orchidaceae) are proposed. A second-step lectotype is selected for Pleurothallis stelidioides and a first-step lectotype for Pseudostelis bradei.

A synopsis is presented of the Neotropical orchid genus Xylobium, wherein 18 species are recognized, including one new species and three varieties. A key is supplied to help identify the species, along with discussion under each entity on its recognition characters, notes where necessary on the synonymy, and a list of specimens examined. The new names are X. miliaceum var. patens, X. undulatum var. portillae, X. undulatum var. variegatum, and X. wilhelminae. At the end of the treatment, a list of excluded taxa is provided, which includes the currently known status of each name. Among those taxa, Dendrobium longifolium is neotypified, and the combinations Cyrtochilum bicolor and Sudamerlycaste insolita are proposed.

Studies of material of Asiatic Tropidia reveals the need to clarify the identities and distribution of various taxa. A full description, illustration, and specimen citation is provided of the recently published T. maxwellii. The previously misunderstood T. capitata is characterized and illustrated. Notes are also supplied on the synonymy and distribution of T. curculigoides, T. namasiae, T. pedunculata, T. reichenbachiana, T. schlechteriana, T. septemnervis, T. squamata, and T. thwaitesii.

Three species are added to the orchid flora of Guyana, one of which, Aspidogyne steyermarkii is a new record, whilst A. reddenii and A. tulamengensis are proposed as novelties.

While 18th-century French scientific institutions such as the Parisian academies and the Jardin du Roi did not accept women among their ranks, the few contributions that women made to Old Regime science have been either forgotten, erased, or attributed to their male counterparts. Mme Dugage de Pommereul's life and work (1733–1782) are a prime example. Although she gained some recognition from 1778–1780, she sank into oblivion in the 19th century when all mentions of her were gradually obliterated. She worked under the supervision of A. Thouin in 1778 and assisted her former professor A.-L. de Jussieu (1748–1836) who entrusted her with the preparation of a study of grasses and a contribution to the Encyclopédie méthodique. Joseph Dombey (1742–1794) dedicated the short-lived Dugagesia margaritifera to her. Ortega Gomez (1741–1818) awarded her a degree from the Royal Academy of Medicine in Madrid, and Linnaeus the Younger named the Pommereulla cornucopiæ in her honor. Piecing together biographical elements with archival evidence, this study provides for the first time a narrative of her life and botanical practice.

Peridiscus lucidus (Peridiscaceae) is recorded for the first time for the vascular flora of Colombia based on a collection from the upper Río Cuyarí, Guianía Department. This locality extends the northwestern distribution of the species in the Amazon basin to the upper Río Negro basin. Notes about the phytogeography and habitats of P. lucidus and an updated overview of the currently known specimens using a geographic distribution map of this taxon are also included. In addition, we provide information on the distinctive vegetative characters that help identify this genus in absence of flowers and fruits. Finally, a lectotype of P. lucidus is newly designated. The discovery of this family in the upper Rio Negro region of Colombia demonstrates the value of field work through alliances between private initiatives and the Kuripaco nation.

We present additional information on and illustrations of Koellensteinia lilijae, a species previously known only from the holotype. A new historical report of Warreopsis colorata from northern Venezuela is presented in an appendix.