Pinus halepensis forests of N.W. Algeria are subjected to frequent fires. During the fire the aboveground parts of plants are completely burned but only a few species are killed. Most perennial herb and shrub species survive owing to their underground organs and regenerate vegetatively in the next moist period. The semi-shrubs regenerate both vegetatively and from seeds. The most intensive growth of the shrub layer occurs during the first 2 years and in the 5th year, it reaches a height of 1-1.5 m. Pinus halepensis is completely killed by the fire and it regenerates from seeds only. The regeneration is retarded during the first 2-3 years, apparently by competition of the rapidly developing shrubs and semi-shrubs with P. halepensis. In the following years, there is a more rapid increase in both density and height, although by the 5th year after fire, the height does not exceed 0.5 m. The young trees overtop the shrub layer between 10 and 15 years after fire. The increase in density and cover supress the lower layers, in particular the herb layer. The reduction in density of trees in the following decades enables the herb layer to reconstitute its composition and cover.This process of regeneration resembles forest growth cycles rather than a secondary succession. The shrub and herb layers maintain their identity as they are mostly formed of the same individuals as before the fire; they merely regenerated their aboveground organs. Only the tree layer regenerates anew after the fire.
In 1994, the Crop Science Society of America (CSSA) appointed an ad hoc committee to study various developmental indexes for crops. As part of this committee's activity, our objective was to compare three developmental indexes for use with switchgrass (Panicum virgatum L.) and two indexes for use with bermudagrass [Cynodon dactylon (L.) Pers]. Two cultivars of switchgrass (Alamo and Cave‐in‐Rook at Stephenville, TX, and Kanlow and Cave‐in‐Rock at Ames, IA) were scored once or twice weekly during primary growth according to the Nebraska index, the Texas Agricultural Experiment Station (TAES) index, and the BBCH (European) uniform decimal code. Two hybrids of bermudagrass (Midland and Tifton‐44 at Fayetteville, AR, and Coastal and Tifton‐44 at Stephenville) were scored once or twice weekly during a spring and summer growth cycle according to the BBCH system and an index developed for bermudagrass (West index). The main difference among scales was that the Nebraska and TAES scales were developed for perennial grasses, whereas the BBCH index is a generic scale with some stage descriptors not applicable to perennial grasses. The indexes share several common stage descriptors, but with different decimal codes. For bermudagrass, the main limitation with the BBCH system was that it applied to grass crops having a well‐defined main stem and sideshoots (tillers) and a relatively uniform maturation of the shoots. The BBCH Principal Growth Stages 2 and 3 were difficult to reconcile with the West system, which does not define tillering, whereas subsequent principal stages are reconcilable with minor modifications. We conclude that the BBCH index would require substantial modification to adapt the system for perennial forage grasses.
A new species of the genus Odontocheila Laporte de Castelnau, 1834 is described from Brazil as Odontocheila parafemoralis sp. nov. Along with other species previously treated as subspecies of O. cajennensis (Fabricius, 1787), the new species is classified here as a species of the O. cajennensis species-complex (within the O. cajennensis species-group). It was commonly confused in collections with O. bipunctata (Fabricius, 1792) and O. femoralis Chaudoir, 1860. Specimens from Itaituba, Rio Tapajoz, Pará (the type locality of the new species) were previously considered by the present author to be aberrant adults of O. oseryi (Lucas, 1857) and were also included within the species in the taxonomic revision of the genus (Moravec 2018). A recent examination of numerous specimens from Itaituba has revealed that they represent an undescribed species, which is diagnostically separated from all taxa of the O. cajennensis species-complex. Consequently, it is described here as new to science. Illustrations of the habitus, diagnostic characters and variability of the new species and distinguishing characters of similar species are presented in colour photographs. A revised key to species of the O. cajennensis species-complex (within the complete O. cajennensis species-group) is presented with reference to the taxonomic revision of the genus (Moravec 2018). An essential map of distribution is also given.
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