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Floral development in the Metrosideros group (Myrtaceae) with special emphasis on the androecium

1996; National Herbarium of NSW; Volume: 6; Issue: 4 Linguagem: Inglês

10.7751/telopea19963031

2200-4025

David A. Orlovich, Andrew N. Drinnan, Pauline Y. Ladiges,

Botanical Studies and Applications

Floral development in the Metrosideros group (Myrtaceae) with special emphasis on the androecium.Telopea 6(4): 689-719.The floral development of eleven taxa in the informal 'Metrosideros group' (Myrtaceae) is described.Two general patterns of androecial development are identified.The multistaminate fascicles of Lophostemon confertus, L. suaveolens, L. lactifluus, Welchiodendron longivalve and Tristaniopsis laurina develop from stamen primordia initiated on antepetalous pre-staminal bulges.In Xanthostemon oppositifolius, X. verticillatus and Lysicarpus angustifolius, which have a complete ring of unfused stamens, often with more stamens in the antepetalous region, pre-staminal bulges do not develop prior to stamen initiation; stamen primordia are initiated directly on the floral tube.Differential hypanthial expansion results in the spreading-out of antesepalous stamens whilst antepetalous stamens remain clustered in front of the petals.Metrosideros collina var.villosa, Tristania neriifolia and Thaleropia queenslandica have fewer stamens, which develop on either small pre-staminal bulges (M.collina) or on the flank of the invaginated floral apex.Staminal arrangement in all the taxa studied is a result of the interaction between the timing of androecial initiation and the available space on the hypanthium.