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In a 2²-month hydrobiological survey of the Rio Ojailén, a tributary of the Rio Guadalquivir in Spain, four aspects of the pollution from an oil refinery and petrochemical complex were considered: physical, chemical, macrobiological and toxicological. Near its source the river receives a combined waste making up 75% of its dry weather flow. The wastes are grossly polluting—from oil, phenols, ammonia, hydrocarbons and other organic materials as well as suspended solids. Though inhibitory to biological degradation, the wastes are gradually purified and diluted with passage downstream and retention in a man-made lake. No macroinvertebrate life is found for 43 km downstream of the complex, in spite of incoming pure streams which were sampled for comparison. Diptera followed by Odonata are the first to return. The effect of the lake on purification is considerable. Toxicity tests of river water upon mosquito fish show a similar decline in toxicity. An attempt has been made to predict the recovery of the river once treatment plants have been installed by the autumn of 1973. [ABSTRACT FROM AUTHOR]

The cytogeographic distribution and morphology of Festuca taxa in sections Bovinae and Scariosae has been compared with the results of experimental hybridization between them. Two groups have been established, the first is predominantly Moroccan and includes F. mairei (2n = 28), F. arundinacea varieties atlantigena forma pseudo-mairei (2n = 56), letourneuxiana and cirtensis (2n = 70). These taxa are closely related to the diploid F. scariosa endemic in the Spanish Sierra Nevada. Their distinctive morphological features are due to the inclusion of the scariosa genome. The second group, predominantly European, including F. arundinacea var. glaucescens (2n = 28) and F. arundinacea var. genuina (2n = 42), is similarly associated with the diploid F. pratensis. It is suggested that evolution in this species complex involved opportunities in a previous era for hybridization between tetraploid taxa now separated geographically. From such hybrids the higher polyploids can be derived. [ABSTRACT FROM AUTHOR]