Variation of Polar Axes and Equatorial Diameters in Pollen Grains of Two Species ofCassia

It is generally accepted that morphology is, within certain limits, constant in pollen grains of a given species.The direct observation of relief and structure of the esine has shown this constancy.When polymorphism appears it is so el-idcnt that it can be detected by a inere glance.Sclerolobirzrn aureunt (Sfelhem L! Salgaclo-Labonriau 1933) and Antonia ouafu (V61io S: Salgado-Labouriau 19G4) present good examples of form variation from oblate to prolate grains.Recently, with the demand for more accurate identification, measurements of different parts of pollen grains arc being used to separate closely related species.Emphasis has been placed on establishing the limits of variation and on adequate methods for their use.Clausen (19G2) showed that the size of pollen grains of Betala is not affected by the position of the catkin within a tree.Nerertheless differences within the same species have been found in a few cases.Diflerences in pollen ineasurements were found in samples of grasses taken in different environmental conditions (Jones S: Newell 1942), in Pinus at different geographical localities (Cain S: Cain 1918), in I~odocarpus within and between populations (Martin 1959).Differences \\-ere also found in the same flower when more than one type of antlier occurs.Trelease (1888) found pollen size differences in several species of Oxalis, Knut and also Tischlcr (see Selling 1947) in two species of Cassia and Hyde & Adams (1933) in Lgfhrum salicaria L.