A distinctive species, Vanilla denshikoira, is described from the North West Amazon, in Colombia, within the Guiana Shield region. The species has morphological features similar to those of species in the Vanilla planifolia group. It is an important addition to the vanilla crop wild relatives, bringing the total number of species in the V. planifolia group to 21. Vanilla denshikoira is a narrow endemic, known from only a single locality, and highly vulnerable to anthropological disturbance. Under IUCN criteria it is categorized CR. The species has potential value as a non-timber forest product. We recommend a conservation program that includes support for circa situm actions implemented by the local communities.

Light is considered a non‐limiting factor for vascular epiphytes. Nevertheless, an epiphyte's access to light may be limited by phorophyte shading and the spatio‐temporal environmental patchiness characteristic of epiphytic habitats. We assessed the extent to which potential light interception in Rodriguezia granadensis, an epiphytic orchid, is determined by individual factors (plant size traits and leaf traits), or environmental heterogeneity (light patchiness) within the crown of the phorophyte, or both. We studied 104 adult plants growing on Psidium guajava trees in two habitats with contrasting canopy cover: a dry tropical forest edge, and isolated trees in a pasture. We recorded the number of leaves and the leaf area, the leaf position angles, and the potential exposure of the leaf surface to direct irradiance (silhouette area of the leaf blade), and the potential irradiance incident on each plant. We found the epiphytes experience a highly heterogeneous light environment in the crowns of P. guajava. Nonetheless, R. granadensis plants displayed a common light interception strategy typical of low‐light environments, resembling terrestrial, forest understory plants. Potential exposure of the total leaf surface to direct irradiance correlated positively with plant size and within‐plant variation in leaf orientation. In many‐leaved individuals, within‐plant variation in leaf angles produced complementary leaf positions that enhanced potential light interception. This light interception strategy suggests that, in contrast to current wisdom, enhancing light capture is important for vascular epiphytes in canopies with high spatio‐temporal heterogeneity in light environments.

En éste artículo describimos la variación fenotípica y ecología de la polinización de la epífita de ramita Rodriguezia granadensis. La especie presenta polimorfismo para el color de las flores (blanco a rosa), lo que lo llevó a hipotetizar que las diferentes formas de color pueden ser polinizadas por diferentes polinizadores. Para evaluar esta hipótesis, se monitorearon cien plantas en campo y se anotó su fenología de floración y polimorfismo en color. Dos picos de floración se presentan en el año. Evaluamos el éxito reproductivo (fitness masculino y femenino) y la visita de los polinizadores potenciales en ambos morfos. Se puso a prueba la producción de frutos por autogamia, geitonogamia, xenogamia y emasculación. La producción de néctar se midió con un refractómetro. Adicionalmente, usamos trampas de fragancia con salicilato de metilo y eugenol para atraer polinizadores potenciales (abejas euglosinas). Presentamos evidencia de la polinización de R. granadensis por abejas euglosinas que buscan néctar. La fluctuación en la producción de néctar y el escaso éxito reproductivo entre los individuos sugiere que la orquídea puede emplear un sistema de atracción/engaño como auto-mimetismo o un fenómeno de recompensas difusas.

Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees (Psidium guajava L.) growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of light interception may be an important dimension of the resource acquisition strategies of long-lived woody plants. Using a temporal approach as the one applied here may improve our understanding of the diversity of crown architectures found across and within environments.

The tropical Andean landscape has been dramatically transformed over the last century with remaining native forest limited to small fragments within a heterogeneous matrix of crops, cattle pastures, and urban environments. We aimed to explore the impact of habitat transformation on the population dynamics in an endemic twig epiphytic orchid located within the undisturbed forest and within modified matrix habitat in two regions with contrasting landscape structures: with a dominant shade coffee matrix and a dominant grassland matrix. Over 2 years, we surveyed 4,650 individuals of the Colombian endemic orchid, Rodriguezia granadensis. We undertook four post-breeding censuses in three sites in each region in both native forest and pasture sub-sites (12 sub-sites; 48 censuses in total), and constructed demographic transition matrices (n = 36). The transition probabilities were calculated using a Bayesian approach and population grow rates were evaluated using asymptotic models and elasticities using transient dynamics. Between regions, higher population growth rate and inertia (defined as the largest or smallest long-term population density with the same initial density distribution) was seen in the shade coffee-dominated landscape. Additionally, population growth rate and damping ratio was higher in forest compared with pasture, with lower convergence time for the forest subsites. These demographic patterns reveal the contrasting levels of population resilience of this orchid in different landscape structures with the more connected shade-coffee dominated landscape permitting some healthier populations with greater population growth and survival in forest than pasture. This study highlights that twig epiphyte colonization of isolated phorophytes in pastures should not be interpreted as a sign of a healthy population but as a temporal transitory period.

Se adelantó la caracterización de la vegetación en la reserva natural La Hondonada, integrando las actividades de docencia e investigación en el programa de Biología en la PUJ Cali. A través de las actividades de campo de la cátedra de Diversidad Vegetal y las actividades de laboratorio y campo del grupo de estudio en Diversidad Vegetal (2013-2016), se adelantó un muestreo de 1000 m2 en un remanente de bosque subandino dentro de una matriz de cultivos y potreros. Se censaron todas las plantas (hierbas, arbustos y árboles) en diez transectos en banda de 50*2 m, documentando la riqueza y abundancia, además de las medidas dasométricas a todos los árboles con DAP mayor o igual a 10 cm. Se recolectaron muestras vegetales para herborización y determinación con bibliografía especializada y comparación con herbarios locales y virtuales (CUVC, COL, JBB). Se encontraron 131 especies pertenecientes a 45 familias botánicas; la familia más diversa Araceae, con 33 especies; las especies más abundantes, Selaginella geniculata en el estrato herbáceo, Faramea occidentalis en el estrato arbustivo; Nectandra macrophylla, Gustavia speciosa y Ocotea caracasana en el estrato arbóreo. Para los árboles se encontró relación entre la abundancia y la dasometría ya que las especies con mayor IVI e IPF son también Gustavia speciosa y Nectandra macrophylla. Se encontró un bosque muy diverso, con una composición y dominancia de especies heredera de la conservación en paisajes fragmentados, se reportan familias botánicas con algún grado de protección y amenaza como Orchidaceae y Lecythidaceae, Nuestros resultados subrayan la importancia de la reserva natural de la sociedad civil La Hondonada, que aportan argumentos a la conservación con base la caracterización de la diversidad vegetal.