A new species of Coccoloba P. Browne (Polygonaceae) from the Brazilian Amazon with exceptionally large leaves

Abstract

We describe and illustrate a new species of Coccoloba (Polygonaceae), named Coccoloba gigantifolia, from the Brazilian Amazon. It resembles Coccoloba mollis Casar, but differs from the latter species by its much larger leaves in the fertile branches. The species has only been recorded in the Madeira River basin, in the states of Amazonas and Rondônia, in the central and southwestern Brazilian Amazon. The description was based on herbarium material, cultivated plants, and individual trees in their natural habitat. We provide illustrations, photographs, and an identification key with morphological characteristics that distinguish the new taxon from the other two related taxa of the Coccoloba sect. Paniculatae, as well as comments on the geographic distribution and conservation status of the species.

Physiological performance of Coccoloba gigantifolia seeds subjected to desiccation and storage

“…The proportion of species with seeds that are sensitive to desiccation decreases as the habitat becomes drier and possibly also cooler (Tweddle et al, 2003). Therefore, seed sensitivity to desiccation is more common in species from moist habitats, such as the one where Coccoloba gigantifolia occurs naturally (Melo et al, 2019).…”

“…Coccoloba gigantifolia (Melo et al, 2019) is a recently described species of the Polygonaceae family, found only in the Rio Madeira basin, in the states of Amazonas and Rondônia, in the center and southwest of the Brazilian Amazon. It grows in open rainforests, secondary forests and scrub forests, at altitudes of 20-100 m, with flat relief and moist, sandy or clayey soils (Melo et al, 2019).…”

“…Coccoloba gigantifolia (Melo et al, 2019) is a recently described species of the Polygonaceae family, found only in the Rio Madeira basin, in the states of Amazonas and Rondônia, in the center and southwest of the Brazilian Amazon. It grows in open rainforests, secondary forests and scrub forests, at altitudes of 20-100 m, with flat relief and moist, sandy or clayey soils (Melo et al, 2019). It has an arboreal growth habit, with a straight trunk, reaching 10-15 m in height; the plants are polygamous-dioecious and, as a result, not all of them produce fruits and seeds; leaves are alternate, spiraled, petiolate, with elliptical blade of 0.6-2.5 x 0.5-1.4 m; anthocarps are globose, pubescent or puberulent, red, vinaceous or purple when mature, measuring 5-8 mm in length; the nucules are globose, smooth, slightly striated, with an acute or pyramidal apex; the seeds have ruminated endosperm (Melo et al, 2019).…”

“…However, there is little information about its biology and virtually no information about its management. The scarce knowledge about the species is more worrying when taking into account the risk of extinction of the species in nature, owing to the restricted area of occurrence and deforestation for expansion of the agricultural frontier and for the construction of hydroelectric plants and highways (Melo et al, 2019). Faced with such a situation, in situ and ex situ conservation strategies should be adopted to avoid the extinction of this species.…”

Tovomita nebulosa (Clusiaceae), a new species from Cerro de la Neblina, Venezuela

“…There are 20 recorded species of Tovomita in Venezuela (see Appendix 1 in Marinho 2019). Although the number of recently described Tovomita species is relatively high, much more remains to be done, given that each new investigation of representative Amazonian collections reveals many potentially undescribed taxa (Frazão and Lohmann 2018;Toledo and Souza 2018;Huamantupa-Chuquimaco et al 2019;Melo et al 2019), including the Venezuelan Amazon (Cabral et al 2016(Cabral et al , 2018Marinho et al 2016aMarinho et al , 2019Nascimento Jr. et al 2019). In the treatment of Tovomita in the Flora of the Venezuelan Guayana, Cuello (1998) defined at least six distinct morphotypes that did not match any previously described species.…”