A Palynological Review for Some Species of Family Boraginaceae Juss. from the Egyptian Flora

Abstract

The pollen grains of 22 species covering 11 genera are investigated. These selected species are represented by the two subfamilies Heliotropioideae and Boraginoideae with 7 tribes. Light and scanning electron microscopic techniques are followed. This work aims to introduce a well-developed identifying constant and valuable features of pollen grains.  General pollen morphological characters are examined: the size, shape, polarity, apertures types & features, colpi characters, endoapertures and tectum characters. Two patterns of grains are observed; hetero- and homoaperturate. Results are significantly variant; grains are monads, mostly minute- or small-sized and prolate or subprolate. Endoapertures shape is lo- or lalongate. Eight pollen types and 2 subtypes are derived from the apertures types & features, and tectum characters. These results are consumed to describe different taxa. A palynological studying of the Boraginaceae is, however, of great taxonomic significance.