| Resumo: |
Oxalis latifolia is a widely distributed weed that mainly affects corn fields, orchards, plant nurseries and gardens. Two forms of the weed have been identified: the common form, with fish-tailed leaflets, bulbils growing on stolons and dark pink flowers, and the Cornwall form, with rounder leaflets, sessile bulbils and whitish-pale pink flowers. In this study, the fresh matter production, expressed as the increase of the bulbs' fresh weight, of both forms was compared during two growing seasons in two locations. The bulbs were grown in pots from spring to autumn, and different aspects of growth were measured at the end of each season. The total fresh matter production, weight of the apical bulb, total weight of the lateral bulbs and number of lateral bulbs differed between the forms, but the mean weight of the lateral bulbs did not. The production of fresh matter was related mainly to the climatic conditions, with both forms of O. latifolia being sensitive to excess rainfall (e.g., > 100 mm) in June and July. The two forms of O. latifolia differed with respect to the fresh matter allocation to the apical or lateral bulbs, suggesting a difference in their growth strategies. The common form developed a light apical bulb and devoted more resources to the lateral bulbs, whereas the Cornwall form developed a heavy apical bulb and many comparatively smaller lateral bulbs. Despite their relative indifference to the soil type, the differences between the two forms suggest that they originated from different climatic regions and that they may differ in their invasive abilities.
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