Refuting the hypothesis of Centinelan extinction at its place of origin.

Scientists' limited understanding of tropical plant communities obscures the true extent of species loss caused by habitat destruction. The Centinelan extinction hypothesis posits an extreme but widely referenced scenario wherein forest clearing causes the immediate extinction of species known only from a single geographic location. It remains unclear, however, whether the disappearance of such microendemics reflects their global extinction or insufficient collection effort at larger scales.

 (Gesneriaceae), an exceptionally small lithophilous new species from the western Andean slopes of Ecuador.

Recent exploratory field expeditions to the western slopes of the Ecuadorian Andes resulted in the discovery of a new species of (Gesneriaceae). J.L.

Evolution of intraspecific floral variation in a generalist-specialist pollination system.

Intraspecific processes impact macroevolutionary patterns through individual variation, selection, and ecological specialization. According to the niche variation hypothesis, the broader ecological niche of generalist species results in an increased morphological variation among individuals either because they are constituted of diversified specialized individuals each exploiting a fraction of the species' niche or because they are constituted of true generalist individuals that experience relaxed selection. To test this hypothesis, we surveyed the individual floral morphology of species of Antillean Gesneriaceae, a group that has transitioned between specialization for hummingbird pollination and generalization multiple times throughout its evolutionary history.

 (Alstroemeriaceae), an exceptionally small new species from the eastern Andean slopes of Ecuador.

Recent field research on the eastern slopes of the Andes resulted in the discovery of a new species of from the Cerro Candelaria Reserve in the Tungurahua province of Ecuador. is the second smallest species in the genus and differs from the smallest by the presence of glutinous trichomes on the ovary, glabrous sepals, and greenish-yellow petals with purple spots. Based on IUCN guidelines, a preliminary conservation status is assigned as Vulnerable (VU).

 (Gesneriaceae), a new lithophytic species from the Sierra de Bahoruco, Barahona Peninsula of southern Hispaniola (Dominican Republic).

A narrowly endemic new species of is described from the Sierra de Bahoruco in the Dominican Republic's Barahona Peninsula of southern Hispaniola. J.L.

 (Phyllanthaceae), a new shrubby species from the Cordillera del Condor in southern Ecuador.

A new species of (Phyllanthaceae) is described from the sandstone Nangaritza Plateau in the Cordillera del Cóndor Region in southern Ecuador. J.L.

 (Gesneriaceae), a new species from the Cordillera Oriental of the Colombian Andes.

A narrowly endemic new species of is described from the Cordillera Oriental of the northern Andes, in the Colombian departments of Caquetá and Huila. J.L.

Two new pendulous epiphytic L. (Gesneriaceae) species from the Chocó forests of the Northern Andes.

Exploratory field expeditions to the Chocó forests in the northwestern slopes of the Ecuadorian and Colombian Andes resulted in the discovery of two new species of (Gesneriaceae). J.L.

 (Gesneriaceae), a new species from the western slopes of the Ecuadorian Andes.

Exploratory field expeditions to the western slopes of the Ecuadorian Andes resulted in the discovery of a new species of (Gesneriaceae). J.L.

Rediscovery of L.E.Skog & L.P.Kvist (Gesneriaceae) at multiple sites in western Ecuador.

We report the rediscovery of the Critically Endangered cloud forest herb , not seen since 1985. In 2019 and 2021, was recorded at five sites in the western foothills of the Ecuadorian Andes, 4-25 km from the type locality at the celebrated Centinela ridge. We describe the species' distribution, abundance, habitat and conservation status and offer recommendations for further research and conservation efforts focused on and the small, disjunct forest remnants it occupies.

Two new species of (Gesneriaceae) from Northwestern South America, including the discovery of the longest flower known in the genus.

Two new species, Clavijo & J.L.Clark, and J.

(Gesneriaceae), a new species from the northwestern Andes of Ecuador.

A new species of is described from the western Andean slopes of the Pichincha Province in northern Ecuador. J.L.

Three new species of (Gesneriaceae) from the western Andean slopes of Ecuador and Colombia.

Three new species of (Gesneriaceae, tribe Gesnerieae) are described from the western Andean slopes of northern Ecuador and southern Colombia. J.L.

New circumscriptions add two northern Andean species to (Gesneriaceae).

Recent studies of type specimens and exploratory research expeditions in the northern Andes have resulted in an updated circumscription and recognition for two species of (Gesneriaceae) in Ecuador and Colombia. A change in the rank from a variety to species is recognized for (Fritsch) Wiehler. The combination (Fritsch) J.

Greater pollination generalization is not associated with reduced constraints on corolla shape in Antillean plants.

Flowers show important structural variation as reproductive organs but the evolutionary forces underlying this diversity are still poorly understood. In animal-pollinated species, flower shape is strongly fashioned by selection imposed by pollinators, which is expected to vary according to guilds of effective pollinators. Using the Antillean subtribe Gesneriinae (Gesneriaceae), we tested the hypothesis that pollination specialists pollinated by one functional type of pollinator have maintained more similar corolla shapes through time due to more constant and stronger selection constraints compared to species with more generalist pollination strategies.

Hummingbird pollination and the diversification of angiosperms: an old and successful association in Gesneriaceae.

The effects of specific functional groups of pollinators in the diversification of angiosperms are still to be elucidated. We investigated whether the pollination shifts or the specific association with hummingbirds affected the diversification of a highly diverse angiosperm lineage in the Neotropics. We reconstructed a phylogeny of 583 species from the Gesneriaceae family and detected diversification shifts through time, inferred the timing and amount of transitions among pollinator functional groups, and tested the association between hummingbird pollination and speciation and extinction rates.

Resolving incongruence: Species of hybrid origin in Columnea (Gesneriaceae).

Speciation by hybridization has long been recognized among plants and includes both homoploid and allopolyploid speciation. The numbers of presumed hybrid species averages close to 11% and tends to be concentrated in a subset of angiosperm families. Recent advances in molecular methods have verified species of hybrid origin that had been presumed on the basis of morphology and have identified species that were not initially considered hybrids.

Speciation within Columnea section Angustiflora (Gesneriaceae): islands, pollinators and climate.

Despite many advances in evolutionary biology, understanding the proximate mechanisms that lead to speciation for many taxonomic groups remains elusive. Phylogenetic analyses provide a means to generate well-supported estimates of species relationships. Understanding how genetic isolation (restricted gene flow) occurred in the past requires not only a well-supported molecular phylogenetic analysis, but also an understanding of when character states that define species may have changed.