The potential for hybridization between Typha angustifolia and Typha latifolia in a constructed wetland

Three Typha taxa are recognized in the central USA: native Typha latifolia (broad-leaved cattail), the invasive Typha angustifolia (narrow-leaved cattail), and a hybrid between the two species, Typha x glauca. Previous authors have suggested that interspecific hybridization is common in cattails. In a 6-year-old constructed wetland in central Ohio, USA, we found that T angustifolia began flowering about 2 weeks earlier than T. latifolia, with female flowers opening several days earlier than male flowers. T. angustifolia shoots were 15 times more abundant and twice as dense as those of T. latifolia. Male flowers of T. angustifolia far outnumbered the male flowers of T. latifolia when the latter species began flowering, such that interspecific, pollination was likely during the short period of overlap. DNA markers (RAPDs) were used to screen for hybrids. These markers corresponded well to other species-specific traits, such as pollen type (monads versus tetrads) and the presence or absence of a gap in the floral spike. We found no putative hybrids based on surveys involving molecular and/or morphological traits. Thus, we did not detect any gene flow between the cattail species, despite opportunities for cross-pollination and F-1 seedling establishment. (C) 2004 Elsevier B.V. All rights reserved.