0000000000113998
AUTHOR
Rolf Rutishauser
Developmental morphology of Apinagia multibranchiata (Podostemaceae) from the Venezuelan Guyanas
Abstract Apinagia ( c. 50 spp.) is the largest genus of American Podostemaceae. Apinagia multibranchiata (Matth.) Royen is a haptophyte endemic to the Venezuelan Guyanas. It fits well with the Podostemoideae bauplan known from other New World genera, such as Marathrum and Mourera . Shoots arise in pairs from filamentous creeping adhesive roots. During the rainy season submerged vegetative shoots grow up to more than a metre long. They are normally unbranched and provided with distichously arranged leaves which are laterally flattened into one plane. The lanceolate leaves may show a fimbriate tip. Tufts of threads are found on the upper leaf surface which faces the sky. When the water recede…
The architecture ofMourera fluviatilis(Podostemaceae): developmental morphology of inflorescences, flowers, and seedlings
Mourera fluviatilis from northern South America is a spectacular member of the Podostemaceae (river-weeds). Its racemelike inflorescences are up to 64 cm long and have 40‐90 flowers arranged in two opposite rows. Inflorescence development starts with the initiation of a double-sheathed (dithecous) bract in a terminal position. All lateral bracts (again dithecous) are initiated in basipetal order along the two flanks of the inflorescence. Each gap between two neighboring bracts contains a single flower. The flowers are bisexual, each with a whorl of 16‐20 ligulate tepals and 14‐40 stamens, which are arranged in one or two whorls. Floral development starts with the formation of a girdling pri…