ULTRASTRUCTURE AND FUNCTION OF THE NECTARIES OF NEW-ZEALAND BRACKEN (PTERIDIUM-ESCULENTUM (FORST F) COCKAYNE)

The ultrastructure of the nectaries and surrounding tissue of New Zeal and bracken (Pteridium esculentum (Forst. f.) Cockayne) is described. There are no differences in the ultrastructure of bracken nectaries fr om New Zealand compared with material from Hawaii (Pteridium decomposi tium Gaud.) and California (Pteridium aquilinum (L.) Kuhn var. pubesce ns Underw.). The ultrastructure changes with the developmental state o f these extrafloral nectaris. While the nectariferous tissue of young and actively secreting nectaries appears densely stained under the lig ht microscope and has distinct ultrastructural features, the differenc e between the secretory tissue and the surrounding parenchyma becomes less obvious as the nectary ages and secretion ceases. A qualitative a ssay for sugar analysis demonstrated that New Zealand bracken nectarie s actively secrete nectar.