Forest Biodiversity Assessment in Peruvian Andean Montane Cloud Forest

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as rega rds biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the ?Bosque de Neblina de Cuyas?, in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity

Insect pollination of Plantago lanceolata L.

IN Britain, Plantago lanceolata is regarded as windpollinated1 and is figured by McLean and Ivimey-Cook2 as a typical example of a long-filament-type wind-pollinated species. It was therefore of interest to observe that around Brisbane this long-filament form is regularly worked for pollen by the honey bee wherever a dozen or so spikes are flowering within a few feet of each other

Dispersai of fleshy diaspores in the seed floras of the south island (New zealand) and tasmania

The native seed-plant floras of South Island (New Zealand) and Tasmania are similar in size but the former is about twice as rich in species with fleshy diaspores than is the latter. In contrast, South Island has far fewer species with arillate or carunculate seeds than Tasmania. These differences in proportions may be attributed to the differential extinction of bird and ant species on the two islands during the Pleistocene Ice ages. Whereas South Island was relatively isolated at the time, Tasmania was closely connected to the Australian mainland providing refuges not available to South Island species. It is postulated that on both islands plants were less affected by glaciation than were animais. The types, sizes and colours of diaspores are similar in the floras of South Island and Tasmania, indicating that the lack of land mammals on the former island is not reflected in the dispersal biology of fleshy diaspores

Vivipary in Eleusine indica (L) gaertn

AT two localities near Brisbane, plants of Eleusine indica, an annual grass, have been observed with inflorescences bearing proliferated spikelets. Such plants were rare and in every instance bore normal as well as proliferated spikelets

Factors affecting the frequencies of wild plant hybrids

The relationships between the frequencies of wild hybrids and certain properties of the parent species and the artificial F1 generation have been investigated from a survey of the literature. There appears to be no correlation between hybrid frequency and the life form of parent species, neither is there any correlation detected between hybrid frequency and the self compatability or otherwise of the parent species. There appears to be a weak correlation between hybrid frequency and the fertility of the artificial F1 generation; also between hybrid frequency and the level of ploidy of the parent species; but neither of these correlations is statistically significant

Attribute correlations in the Poaceae (grasses)

Investigation of correlations between a number of two‐state attributes for a sample of grass genera revealed that a high proportion of the correlations were statistically significant. There were proportionately more correlations between attributes from the same organ than between attributes from different organS. Furthermore, attributes associated with the fruit and leaf were found to be more closely correlated with attributes other than those of the flower and spikelet, thereby indicating fruit and leaf attributes to be important in the classification of the grasseS. It is considered that the correlations have arisen in part as a result of the phylogenetic origins of the genera and in part as a response to natural selection determining distribution of genera adapted to present‐day habitats. Copyrigh

The taxonomic and evolutionary significance of leaf longevity

The half‐lives of leaves of 202 taxa of vascular plants were estimated mostly from the literature and ranged from 1 to 350 wk. The longevity of leaves in the plant groups studied is in the order Pinophyta > Pteridophyta > Liliatae > Magnoliatae. Substantial differences are evident between the superorders of flowering plants proposed by Dahlgren and the subclasses proposed by Cronquist. The mean leaf half‐life for families of Magnoliatae was shown to be inversely related to their Advancement Index. Length of life of leaves, therefore, appears to have taxonomic significance, with more primitive vascular plants tending to have longer‐lived leaves than the more advanced. The ecological significance of leaf half‐life is less clear, except in that annual leaf fall is not necessarily associated with deciduousness. The capacity to shed individual leaves may give the angiosperms a flexibility in environmental response which allows them a competitive advantage over the gymnosperms except in the most stressful habitats