Pollen morphology of Palmeria scandens and Wilkiea huegeliana (Monimiaceae)

Abstract

Palmeria scandens F. Muell, and Wilkiea huegeliana (Tul.) A.DC., of the subfamily Monimioideae of the Monimiaceae, have small inaperturate (omniaperturate), apolar, radiosymmetric, globose-spherical pollen, which is echinate (spinulose) in Palmeria and gemmate in Wilkiea. Exine in Wilkiea consists of a discontinuous tectum of globose gemmae which protrude from an exinous region of “radial processes” which abut onto the intine. In Palmeria the exine consists of spinules which are attached to a zone of even thickness. It contains sporopolleninous elements, more or less rod-shaped, which are circumferentially aligned in inner and outer regions of the zone and predominantly radially aligned in the central part. No “radial processes” were observed in Palmeria. A foot layer and endexine are absent in both genera. In Wilkiea the intine is relatively homogenous and about the same thickness as the exine, but in Palmeria the intine comprises two zones—an outer channelled zone approximately the same thickness as the exine (excluding spinules) and a somewhat thinner inner zone, similar to the entire intine of Wilkiea. Comparisons are made with pollen of other Monimiaceae s.l. and some other families of the woody Ranalean order Laurales.