Comparative Pollen Morphology of the Madagascan Genera of Myristicaceae (Mauloutchia, Brochoneura, and Haematodendron)

Abstract

Pollen of all three genera of Madagascan Myristicaceae (Mauloutchia Warburg, Brochoneura Warburg, and Haematodendron R. Capuron) and all species except one was studied with light, scanning electron, and transmission electron microscopy. A new term interstitium is introduced. Formal generic pollen descriptions are given for each genus. The distinctness of the frequently united genera Mauloutchia and Brochoneura is confirmed, as well as that of the recently described new genus Haematodendron. Mauloutchia has the most primitive exine structure and Brochoneura the most primitive sculpturing, while pollen of Haematodendron is more advanced in both regards. Mauloutchia is extremely eurypalynous, particularly with regard to exine structure and sculpturing, and to a lesser extent aperture type and pollen size. Stages in the evolution of columellae from a primitively columellaless condition can be observed within the pollen of the putatively primitive genus Mauloutchia.

Key Words:

• Myristicaceae
• Madagascar
• pollen morphology