On the pollen of Salpianthus (Nyctaginaceae)

Abstract

Pollen grains of the three recognized species of Salpianthus (Nyctaginaceae), i.e., S. arenarius Humb. & Bonpl., S. macrodontus Standl., and S. purpurascens (Cav. Ex Lag.) Hook &. Arn. were studied with special reference to the presence and number of spinules and perforations per area unit, size, shape and polar area index. Image analysis of SEM‐micrographs at a standard magnification of χ 15,000 and in a specific area of 6 χ 6 cm was performed by means of Leica Quantimet 570. Counts were also made manually and the two compared statistically. Shape, polar area index, and size were calculated by different statistical tests. S. macrodontus has larger pollen grains than S. arenarius and S. purpurascens; S. arenarius is more subprolate than the other two while S. purpurascens has a larger polar area index than S. arenarius and S. macrodontus. The number of spinules and perforations could not be used to separate the three species as intraspecific variation is greater than interspecific variation. No correlation between pollen morphology and leaf shape could be proved.