Twining stems of plants are very common in extant tropical and subtropical forests, and the climbing growth habit of plants may be an evolutionary innovation and ecological adaptation to either closed, shady or open, ...Twining stems of plants are very common in extant tropical and subtropical forests, and the climbing growth habit of plants may be an evolutionary innovation and ecological adaptation to either closed, shady or open, edge environments. However, the origin of handedness in climbing plants remains unclear. Here we report a Miocene (ca. 16 million years ago) macrofossil from the Shanwang Formation of Shandong Province, Eastern China, unequivocally exhibiting the first direct fossil evidence for a left-handed, stem-twining growth habit in plants. This fossil plant bears a thicker, slightly curved supporting stem (2 - 3.5 mm wide), which is loosely, spirally twined by a thinner stem (1.5 - 2 mm wide), possibly representing part of distal branches from a liana or vine.展开更多
Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricte...Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100 m intervals starting from 1500 to 3400 m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r = −0.985, −0.984, −0.981, respectively; all p < 0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p < 0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.展开更多
文摘Twining stems of plants are very common in extant tropical and subtropical forests, and the climbing growth habit of plants may be an evolutionary innovation and ecological adaptation to either closed, shady or open, edge environments. However, the origin of handedness in climbing plants remains unclear. Here we report a Miocene (ca. 16 million years ago) macrofossil from the Shanwang Formation of Shandong Province, Eastern China, unequivocally exhibiting the first direct fossil evidence for a left-handed, stem-twining growth habit in plants. This fossil plant bears a thicker, slightly curved supporting stem (2 - 3.5 mm wide), which is loosely, spirally twined by a thinner stem (1.5 - 2 mm wide), possibly representing part of distal branches from a liana or vine.
基金supported by the Ethiopian Biodiversity Institute
文摘Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100 m intervals starting from 1500 to 3400 m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r = −0.985, −0.984, −0.981, respectively; all p < 0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p < 0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.
