Observation on Floral Morphology of Typha angustifolia, with Implications for Delimitating the Species and T. domingensis

The floral morphology and structure of Typha angustifolia L.(Typhaceae) were studied by examining a large number of specimens and observing population variation both in field and cultivated plants.A new description with respect to morphology of the apex of bracteole, hair of pistillate flowers, and the number of abortive pistillate flowers of a spikelet were provided and illustrated.Additionally, the variability of lengths of stigma, bracteole and hair of the fertile pistillate flower during the mature period were addressed based on observation of cultivated plants.T.angustifolia was very similar to T.domingensis in overall gross mor-phology.Several characters, however, can be used to separate them.In T.angustifolia the apex of bracteoles was dark brown and opaque and spikelets consisted of 3 or 4 abortive pistillate flowers.In T.domingensis the apex of bracteoles was pale and translucent and spikelets consisted of 1 or 2 abortive pistillate flowers.Observations on T.angustifolia both in the field and on cultivated plants further revealed that it had a great degree of variability in relative length of bracteole and stigma, suggesting that these characters should not be used for specific diagnosis.The results showed that T.angustifolia and T.domingensis differed in color of the apex of bracteole and the number of abortive flowers of a spikelet, providing a basis for the delimitation between the two species.