Structure of arboreal and herbaceous strata in a neotropical seasonally flooded monodominant savanna of Tabebuia aurea.

Large areas in the Pantanal wetland are covered by monodominant formations, e.g. typical landscapes with local names such as "paratudal", dominated by T. aurea. Studies on structure of these formations generally include only woody strata, consequently the species richness registered is usually low due to the absence of the 'ground layer' of herbaceous and others low species. We recorded 13 species, 12 genera and 11 families for the arboreal stratum. Considering arboreal flora without the dominant (T. aurea) individuals showed great establishment in relation to the flood level between 35 - 45 cm while the individuals of the dominant species of 30 - 45 cm. The diameter distribution revealed that the population of T. aurea did not show the reverse J curve, the usual pattern for species in constant regeneration, also evidenced in inconstant Licourt quotient, indicating an episodic recruitment that could lead to future changes in structure. In the herbaceous strata we recorded 78 species, included in 62 genera and 27 families. Using plots method we sampled 46 species, 40 genera and 22 families, while in line interception we found 65 species distributed in 57 genera and 26 families. The floristic similarity of Sørensen between both methods was 59.4%, with 33 species in common, and the method of line interception was more efficient in detecting richness, with 35% more species found in the same time. According to the methods of plots and line interception applied on the woody stratum, our results gave similar detailed information on the structure of this type of savanna, and in spite of being monodominant it shows high species richness when the herbaceous stratum is taken into account. Plots and line interception methods showed similar results for the woody stratum and high species richness of the herbaceous stratum.

Observations on the vegetation of northeastern Mato Grosso II. Forests and soils of the Rio Suiá--Missu area.

The vegetation of the well drained soils along the Suiá--Missu road in the Serra do Roncador region of NE Mato Grosso is Evergreen Seasonal forest of Amazonian type. The area lies close to the meeting place of the Amazonian forest (the hylaea) and the cerrado (savanna) formation of Central Brazil. The structure of the forest is simple: the canopy is at about 18--23 m, and is exceeded by a few scattered emergents; no recognizable strata can be distinguished among the understorey trees and the shrub and herb layers are sparse. Table 1 lists the most important species and gives information on stratification and general distribution. Most of the species appear to have a hylaean centre of distribution but extend into other vegetation types. The forest differs from related communities which lie closer to the cerrado/forest boundary in its greater height and luxuriance, the presence of additional tall tree species, and the great reduction in abundance of a cerrado floristic element. A survey on the Xavantina--São Felix road allowed us to extend previous observations on the distance to which the cerrado tree Pterodon pubescens extends into the forest. The results obtained indicate a considerable extension of forest into cerrado during the life of an individual tree. A characteristic low forest occurs in the flood plain of the Rio Suiá--Missu while Swampy Gallery forests occur on permanently waterlogged soils around the headwaters of streams. The well drained soils of the Suiá--Missu forest are very uniform, deep latosols (oxisols) of very dystrophic nature with pH (in water) between 4.0 and 5.0 (see table 2, p. 203).

Three hundred years of botany in Edinburgh.

This week the tercentenary of the Royal Botanic Garden, Edinburgh, is being celebrated with, among other things, the opening of an exhibition hall given by an anonymous donor. This article traces the fortunes of the Garden during the past three hundred years.