SummaryBetween 1959 and 1988, three populations of purple-flowered terrestrial orchids attributable to Dactylorhiza subgenus Dactylorhiza were discovered in Canada. The populations at Timmins, Ontario, and St John's, Newfoundland were strongly marked on both flowers and leaves, in contrast with the anthocyanin-deficient population at Tilt Cove, Newfoundland. All three populations have since experienced a wide range of taxonomic assignments; debates are also ongoing regarding their origin and most appropriate conservation status. Here, we address these questions by combining detailed in situ morphometric analyses based on 52 characters with allozyme profiles and data from nrITS, 15 plastid microsatellites and seven nuclear microsatellites. The allozyme data alone are sufficient to both confirm allopolyploidy and categorically refute past assignments of these populations to D. incarnata, D. maculata, D. fuchsii, D. majalis or D. purpurella. Several morphometric characters, nuclear microsatellites and nrITS all reliably distinguish each of the three study populations, whereas the two sampled subpopulations from St John's proved near-identical morphologically. In contrast, morphological variation within each of the three populations is strikingly low, particularly in characters other than those influenced by plant vigour. Similarly, compared with 14 European populations, the three Canadian populations proved genetically impoverished (two were near-invariant) and likely experienced recent, extreme genetic bottlenecks during establishment. The three populations differ substantially, both morphologically and molecularly, therefore probably representing independent immigration events. Although clearly attributable to D. praetermissa, all three populations deviate significantly in morphology and DNA data from comparable populations sampled across Europe, preventing identification of their precise geographic origins. Any attempt to determine their mode or origin — through natural long-distance transport, or accidental or deliberate introduction by humans – is challenged to explain why three lineages of a single European Marsh-orchid species, each in different ways atypical of that species, arrived independently in North America whereas no other European dactylorchid species has become established there.

SummaryThe flora of limestone karsts is exceptionally rich, due in particular to the wide array of microhabitats that limestone outcrops support. However, in Peninsular Malaysia limestone outcrops are heavily exploited for the quarry industry, cave temples, leisure venues and the development of geoparks, hence the limestone flora is amongst the most threatened biodiversity in the Peninsula. The 95 limestone karsts in Perak are currently known to support 538 species, representing c. 44.2% of the total limestone flora of Peninsular Malaysia. Of these, 13.2% (71 species) are endemic to the Peninsula of which 10 species are hyper-endemic (i.e. restricted to a single karst), 108 (20%) are threatened with extinction and 6 are considered likely to be Extinct. Typical of limestone in Peninsular Malaysia, a single karst harbours only a fraction of the total limestone flora such that a network of karsts is required to capture maximum plant diversity. Through evaluation of data from field surveys, herbarium specimens and the literature, 27 of the Perak karsts were found to trigger Important Plant Area (IPA) status, i.e. they harbour important populations of threatened species, outstanding botanical richness and/or are important examples of threatened habitats that in Perak include the foothills and limestone forest. Fifteen karsts were identified for priority conservation measures based on Conservation Priority Scores (CPS), a quantitative methodology based on endemic and threatened status. With the addition of two species-rich karst sites, 17 karsts are recommended as the first iteration of the network of priority IPA sites for Perak that together conserve 90% (483 species) of the Perak limestone plant diversity, 93% (66) of the endemic species and 94.4% (102) of the threatened species. CPS is found to be more reliable than using total species richness for assessing conservation importance and we also demonstrate that karst size and isolation are not primary indicators of range-restricted plant diversity. Significant knowledge gaps still exist, with 59 karsts in Perak without botanical surveys, and with many rare species having not been recollected for over 30 years, emphasising the need for further botanical research in these important and threatened landscapes.

SummaryA short visit to four Colombian herbaria in 2022 is highlighted as an example of modern-day herbarium plant hunting which resulted in the discovery of 14 new species: Aphelandra guacharorum J.R.I.Wood, A. montis-tusae J.R.I.Wood & Hoyos-Gómez, Justicia betancurii J.R.I.Wood, J. chloroleuca J.R.I.Wood, J. cristalina J.R.I.Wood & Hoyos-Gómez, J. daironcardenasii J.R.I.Wood & Hoyos-Gómez, J. ipanorensis J.R.I.Wood, J. lutescens J.R.I.Wood & Hoyos-Gómez, J. macuirensis J.R.I.Wood, J. perijaensis J.R.I.Wood, J. reniformis J.R.I.Wood, J. rheophytica J.R.I.Wood & Hoyos-Gómez J. santanderana J.R.I.Wood & Hoyos-Gómez and Ruellia rheophytica J.R.I.Wood & Hoyos-Gómez. These are described and illustrated with line drawings. Additionally, a full description and line drawings of two poorly known species, Justicia hochreutineri J.F.Macbr. and J. trianae (Leonard) J.R.I.Wood are provided. Notes are provided on 21 other species drawing attention to new records for Colombia, rediscoveries and taxonomic issues. Justicia hochreutineri J.F.Macbr., J. pilosa (Ruiz ex Nees) Lindau, J. zamorensis Wassh. and Stenostephanus lasiostachyus Nees are recorded for the first time for Colombia. Justicia pampolystachys Leonard is treated as a synonym of J. hyperdasya Leonard. Poikilacanthus moritzianus (Nees) Lindau is shown to be restricted to Venezuela. Adhatoda pilosa Ruiz ex Nees is lectotypified. Attention is drawn to the number of rheophytes in Colombian Acanthaceae and to the importance of the Río Claro and Río Samaná Norte area of Antioquia as a centre of plant diversity.

SummaryOlearia exilis S.Moore var. subacuta J.Kost. is considered conspecific with Olearia dibrachiata D.J.N.Hind & R.J.Johns following a re-examination of both Koster’s protologue diagnosis and its type (and paratype) material.

SummaryWe describe and illustrate Clusia salicifolia (Clusiaceae) a new species from Central America. This new species is different to all related species for its hemiepiphytic habit, narrow leaves with acute to acuminate apex, reticulate resin canals, staminate flowers with quadrangular androecium with 30 – 47 free stamens, and pistillate flowers with 4 stigmas and 4 pairs of stamen-like staminodia. The species is known from a limited number of localities in lowland wet forests in Costa Rica and Panama and is here assessed as endangered under the IUCN criteria.

SummaryA new species of Apocynaceae from Atlantic Central Africa, Voacanga madureirae Paiva, O.Lachenaud & Covelo, is mapped, described and illustrated. It occurs on the Gulf of Guinea islands of Príncipe (São Tomé and Príncipe) and Bioko (Equatorial Guinea) and in the highlands of western Cameroon. The new species differs from other African Voacanga by its calyx distinctly exceeding the corolla (vs shorter or at most equalling it). It is further separated from V. chalotiana Pierre ex Stapf by the presence of a row of colleters in the upper half of the calyx (not near the base) and from other Central African species by its syncarpous fruits and almost straight (not strongly twisted) corolla tube. It is assessed as Near Threatened according to IUCN criteria.

SummaryLasjia griseifolia Utteridge & Brambach, a member of the Proteaceae, is described and illustrated as a new species from the Indonesian island of Sulawesi. The new species is similar to L. erecta, also from Sulawesi, and morphological differences between the taxa are discussed; a line illustration and detailed notes on the conservation status are provided.

SummaryA summary of the species of Pyrostria from continental Africa is presented, including full descriptions of three new species, P. makovui, P. namacubiensis and P. rovumensis from the coastal forests of the Tanzania-Mozambique border region, and one new subspecies, P. lobulata subsp. bridsoniae from Zambia. Pyrostria makovui is the first species with plurilocular (3-lobed) fruits and the second hermaphrodite species for the study area, characters that are otherwise found mainly in taxa of Pyrostria from Madagascar and surrounding islands. Five of the 16 species treated in this synopsis remain undescribed because they are known only from incomplete material. A key to the species of Pyrostria occurring in continental Africa is presented and notes on the distribution, habitat and relevant taxonomic considerations are provided, along with an assessment of the conservation status (extinction risk) for each species. The Coastal Forests of Eastern Africa Biodiversity Hotspot is found to be a centre of diversity for Pyrostria, with the Rovuma Centre of Plant Endemism in Mozambique and Tanzania being particularly rich in endemic species.