SERIANTHES Benth. (Leguminosae-Mimosoideae-Ingeae)

The genus Serianthes was erected by Bentham to accomodate plants which Wallich had called Inga grandiflora, from Singapore, and those which Bertero had called Acacia myriadenia, from Tahiti. It has been accepted from the first, as it is amply distinct from Acacia and reasonably so from Inga. though it is usually placed in the tribe Ingeae. Serianthes is widespread in the southwest Pacific, usually, though not always, occurring on islands, frequently on calcareous or serpentine rocks or their derived soils. It is seldom abundant, though in places common. In habit it varies from a dwarf tree or large shrub to a forest giant. It is reported to be an excellent timber tree, but seems nowhere to be abundant enough to be important commercially. Since Bentham's original description in 1844, eleven additional species and one variety have been ascribed to it in addition to the original S. grandiflora. Three of these do not belong in Serianthes. Most of the specimens in herbaria, excepting those called S. grandiflora, have been misidentified, usually being placed in S. myriadenia. Although I first saw this genus growing and collected it in Raivavae and Rurutu in 1934, my interest in it was aroused by failure, in 1950, to find a satisfactory disposition for specimens collected in Palau, similar to those that Kanehira had referred to S. grandiflora, which they clearly were not. The more I tried to make sense of the herbarium material available in a number of herbaria the more frustrating the problem became. Notes were accumulated in a most haphazard and unsystematic manner, as I had no intention of doing more than identifying my Micronesian material. Finally it became evident that over half of the entities discernible in the material examined were undescribed, and I felt a certain obligation to work up at least a synopsis of the genus

REVISION OF ALBIZIA Sect. PACHYSPERMA (Leguminosae-Mimosoideae)

In the course of revising the genus Serianthes Benth. (Reinwardtia 5: 293-317. 1960) it was necessary to account for several names which had been proposed in Serianthes but which applied to species belonging to a group that seems better placed in the genus Albizia. ) After some further study, the present treatment of this group, here regarded as constituting Albizia section Pachysperma, was brought together. Owing to the scarcity of material of most of the species concerned, as well as to the difficulty in understanding inflorescence morphology in some of the species from herbarium specimens alone, this paper is of necessity to be regarded as only preliminary. It may, however, serve to direct attention to the fact that the species involved do form a coherent group, with a number of common characters as well as a most peculiar inflorescence that needs much further study. Two new species and two new varieties, as well as two transfers, are proposed

Vegetation of Guam

75 p., 40 p. of plates : ill., map. ; 27 cm.Includes bibliographical references (p. 74-75)

Natural and anthropogenic changes to mangrove distributions in the Pioneer River Estuary (QLD, Australia)

We analyzed a time series of aerial photographs and Landsat satellite imagery of the Pioneer River Estuary (near Mackay, Queensland, Australia) to document both natural and anthropogenic changes in the area of mangroves available to filter river runoff between 1948 and 2002. Over 54 years, there was a net loss of 137 ha (22%) of tidal mangroves during four successive periods that were characterized by different driving mechanisms: (1) little net change (1948– 1962); (2) net gain from rapid mangrove expansion (1962–1972); (3) net loss from clearing and tidal isolation (1972–1991); and (4) net loss from a severe species-specific dieback affecting over 50% of remaining mangrove cover (1991–2002). Manual digitization of aerial photographs was accurate for mapping changes in the boundaries of mangrove distributions, but this technique underestimated the total loss due to dieback. Regions of mangrove dieback were identified and mapped more accurately and efficiently after applying the Normalized Difference Vegetation Index (NDVI) to Landsat Thematic Mapper satellite imagery, and then monitoring changes to the index over time. These remote sensing techniques to map and monitor mangrove changes are important for identifying habitat degradation, both spatially and temporally, in order to prioritize restoration for management of estuarine and adjacent marine ecosystems

Sensitivity of Metrics of Phylogenetic Structure to Scale, Source of Data and Species Pool of Hummingbird Assemblages along Elevational Gradients

Patterns of phylogenetic structure of assemblages are increasingly used to gain insight into the ecological and evolutionary processes involved in the assembly of co-occurring species. Metrics of phylogenetic structure can be sensitive to scaling issues and data availability. Here we empirically assess the sensitivity of four metrics of phylogenetic structure of assemblages to changes in (i) the source of data, (ii) the spatial grain at which assemblages are defined, and (iii) the definition of species pools using hummingbird (Trochilidae) assemblages along an elevational gradient in Colombia. We also discuss some of the implications in terms of the potential mechanisms driving these patterns. To explore how source of data influence phylogenetic structure we defined assemblages using three sources of data: field inventories, museum specimens, and range maps. Assemblages were defined at two spatial grains: coarse-grained (elevational bands of 800-m width) and fine-grained (1-km2 plots). We used three different species pools: all species contained in assemblages, all species within half-degree quadrats, and all species either above or below 2000 m elevation. Metrics considering phylogenetic relationships among all species within assemblages showed phylogenetic clustering at high elevations and phylogenetic evenness in the lowlands, whereas those metrics considering only the closest co-occurring relatives showed the opposite trend. This result suggests that using multiple metrics of phylogenetic structure should provide greater insight into the mechanisms shaping assemblage structure. The source and spatial grain of data had important influences on estimates of both richness and phylogenetic structure. Metrics considering the co-occurrence of close relatives were particularly sensitive to changes in the spatial grain. Assemblages based on range maps included more species and showed less phylogenetic structure than assemblages based on museum or field inventories. Coarse-grained assemblages included more distantly related species and thus showed a more even phylogenetic structure than fine-grained assemblages. Our results emphasize the importance of carefully selecting the scale, source of data and metric used in analysis of the phylogenetic structure of assemblages

Vegetation of the Society Islands

The vegetation of the Society Islands, 16°-18° south of the equator, in the wet SE trade wind belt, is described. The flora is primarily of Indo-Malayan derivation with a few New Zealand, Australian, American, and Hawaiian elements. There is little doubt that the volcanic islands at the time of human arrival, perhaps 4000 yr ago, were forested from mountaintop to seashore. The original vegetation consisted of broad-leaved, usually hygrophilous, montane rainforest. There was an abundance of shrub and small tree species, and terrestrial ferns dominated the ground layer. The sequence of vegetation from forest on the coastal zone and in deep valley bottoms through montane rainforest, mossy or cloud forest, and mossy scrub-covered crests and peaks is distinguished. With the arrival of the Polynesians, nonindigenous plant species were introduced for food, medicine, and fiber,and "camp followers" arrived accidentally. Native species, especially in the lowland coastal zone, were replaced with coconut groves; taro marshes; and valley-bottom forests of mape, breadfruit, and bamboo. The advent of Europeans brought further, often disastrous, change as newly introduced goats and pigs and logging and clearing opened up originally closed formations. Exotic species such as mango and guava came to dominate the vegetation in some places. The flora of the five atolls and the barrier-reef islets is essentially that of strand habitats throughout the Indo-Pacific and is impoverished. There was a mixed broad-leaved forest of several common widespread strand species such as Pisonia, Guettarda, Pandanus, etc., and the halophytic Tournefortia and Scaevola toward the seaward periphery. The original vegetation has also been changed by human activity, replaced by coconut and breadfruit groves and, in wet places, by taro pits. The vegetation patterns of the individual islands are also described

Official plant names

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Davallia solida

Pteridophyte

Trigonospora calcarata

Pteridophyte