Aspects of Floral Morphology and Development in the Seagrass Syringodium filiforme (Cymodoceaceae)

Abstract

Inflorescences in S. filiforme are initially racemose and subsequently extensively cymose, with terminal units referred to as flowers. The species is dioecious. Each unit is normally enclosed by a pair of bracts which may subtend renewal shoots. The male flower consists of 4 pr of microsporangia which arise by equal subdivision of 2 lobes of the floral apex. Each pair of microsporangia is associated with a late-developing protuberance, which collectively fuse to form a perianth ridge, soon obscured by the enlarging microsporgania. The female flower is naked and consists of 2 carpels which arise separately on the floral apex. The carpel is initially peltate but matures as a closed structure with a single pendulous ovule and 2 styles. The homology of these structures with the parts of a normal flower is discussed and compared with several related genera [Lepilaena bilocularis, Alteinia filiformis and Vleisia aschersoniana] for which similar information is available.