Nachruf. (A. Goffin.)

Ohne Zusammenfassung     

Aspidistra albopurpurea,A. khangii,A. lubae and A. stellata spp. nov. (Asparagaceae,Convallariaceae s.s.) from Indochina

Aspidistra albopurpurea, A. khangii, A. lubae and A. stellata discovered recently are described and illustrated as species new to science. All novelties are local endemics of northern Vietnam and southeastern Laos. Aspidistra albopurpurea is unique in the genus with a white/red stigma in striking contrast to the large milk‐white tube base. Aspidistra stellata belongs to a group of species with extraordinary long and narrow lineate perigone lobes. Aspidistra khangii and A. lubae belong to a small group of species having erect, vertical shoots. The first species is easily distinguished by its stout stem, down‐curved peduncle and obpyramidal, container‐shaped perianth. Aspidistra lubae has characteristic horizontal, peduncles and urceolate flowers. Besides the type variety, A. lubae includes var. lancifolia, which differs in its erect, lanceolate, immaculate, shortly petiolate leaves. Both varieties of A. lubae were found growing, often intermixed, in the same locality in very similar ecological conditions.     

A contribution to the embryology of Desmodium motorium (Houtt.) Merr. (= D. gyrans (L.f.) DC.) (Fabaceae)

Abstract

The anthers are tetrasporangiate. The anther wall comprises epidermis, fibrous endothecium, middle layer and tapetal layer. The tapetum is of the Glandular type and its cells remain uninucleate. Meiosis in pollen mother cells is normal and simultaneous cytokinesis leads to the formation of tetrahedral and decussate microspore tetrads. The pollen grains are shed at 2-celled stage. The ovule is campylotropous, bitegmic and crassinucellate. Meiosis in megaspore mother cell results in the formation of linear or occasionally T-shaped megaspore tetrad. The chalazal megaspore develops into Monosporic Polygonum type of embryo sac. Endosperm development is of the Nuclear type.     

Stream macroinvertebrate response to catchment urbanisation (Georgia, U.S.A.)

SUMMARY 1. The effects of catchment urbanisation on water quality were examined for 30 streams (stratified into 15, 50 and 100 km² ± 25% catchments) in the Etowah River basin, Georgia, U.S.A. We examined relationships between land cover (implying cover and use) in these catchments (e.g. urban, forest and agriculture) and macroinvertebrate assemblage attributes using several previously published indices to summarise macroinvertebrate response. Based on a priori predictions as to mechanisms of biotic impairment under changing land cover, additional measurements were made to assess geomorphology, hydrology and chemistry in each stream. 2. We found strong relationships between catchment land cover and stream biota. Taxon richness and other biotic indices that reflected good water quality were negatively related to urban land cover and positively related to forest land cover. Urban land cover alone explained 29–38% of the variation in some macroinvertebrate indices. Reduced water quality was detectable at c. >15% urban land cover. 3. Urban land cover correlated with a number of geomorphic variables such as stream bed sediment size (–) and total suspended solids (+) as well as a number of water chemistry variables including nitrogen and phosphorus concentrations (+), specific conductance (+) and turbidity (+). Biotic indices were better predicted by these reach scale variables than single, catchment scale land cover variables. Multiple regression models explained 69% of variation in total taxon richness and 78% of the variation in the Invertebrate Community Index (ICI) using phi variability, specific conductance and depth, and riffle phi, specific conductance and phi variability, respectively. 4. Indirect ordination analysis was used to describe assemblage and functional group changes among sites and corroborate which environmental variables were most important in driving differences in macroinvertebrate assemblages. The first axis in a non‐metric multidimensional scaling ordination was highly related to environmental variables (slope, specific conductance, phi variability; adj. R²=0.83) that were also important in our multiple regression models. 5. Catchment urbanisation resulted in less diverse and more tolerant stream macroinvertebrate assemblages via increased sediment transport, reduced stream bed sediment size and increased solutes. The biotic indices that were most sensitive to environmental variation were taxon richness, EPT richness and the ICI. Our results were largely consistent over the range in basin size we tested.